Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study

Tomonori I, Issei S, et al.
AJO-DO Feb, 2013:235-245
                                                                 

March 7, 2014
Dr. Sung-ja Kang

[초벌원고]

Anyone who has practiced orthodontics for a significant period of time has most likely had patients who presented with nasal obstruction that leads to mouth breathing, results in lower tongue posture, a constricted V-shaped maxillary dental arch, all of which can  affect normal growth.

[수정원고]

Chronic upper airway obstruction has been associated with low tongue posture. Studies have shown that RME increases nasal width and volume, which is believed to diminish the resistance to nasal airflow. Studies have also shown that RME can result in patients’ changing their breathing pattern from mouth breathing to nasal breathing. The question that hasn’t yet been answered is what effect a RME has on tongue posture.

In a recent study, title of “Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study” by Tomonori Iwasaki et al, which appeared in the February, 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, the authors address this question.

The sample for this study consisted of 28 patients approximately 10 years of age who required RME treatment. Cone-beam computed tomography images were taken before and after RME treatment. A second group of 20 patients of similar age who required orthodontic treatment but not RME, had CBCT images taken at similar times.

The CBCT images were used to analyze nasal air ventilation, tongue posture, and pharyngeal airway volume. Computed fluid dynamics were used to determine the presence of any functional obstruction of the nasal airway. When the authors evaluated this data, what did they find?

After RME, the intraoral airway volume decreased significantly, and total pharyngeal airway volume and the retropalatal airway volume significantly increased. Additionally, tongue posture was raised. The bottom line of this study is that RME not only improves nasal obstruction, but also improves tongue position. The advent of cone-beam computed tomography has allowed researchers to develop better 3-dimensional anatomic evaluations which can lead to more accurate data analysis. You can find this article in the February 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Recovering From Canine Bracket Failure During Forsus Treatment

Rizwan M, Hemanth M, et al.
J Clin Orthod 2013;47:108.

March 14, 2013
Dr. Ha-yeon Park

[초벌원고]

If you used Forsus springs or other Class Ⅱ corrector springs, you’ve probably had the experience of a lower canine bracket failure, which with a constant pressure from the Forsus spring has displaced the canine significantly from the arch. The classic recovery process would be to remove the Forsus spring, realign the lower arch and then replace the spring once realigned. This can cause the delay in treatment due to the time lost for realignment.

[수정원고]

A short article in the Pearls section of the Journal of Clinical Orthodontics provides an alternative recovery method for such a situation without the loss of treatment time. The short communication is called “Preventing delays in Forsus treatment after canine bracket failure” and I want to describe the authors’ suggested technique for you.

When a canine becomes significantly displaced following bracket failure, the suggestion is that a crimpable hook can be placed on the archwire to create a stable anchor for the Forsus push rod. The original archwire is kept in place as a base arch and an auxiliary .014" nickel titanium wire is placed in the canine bracket and over the base archwire to reposition the canine while the Forsus spring is still in place and active.

Once the canine is realigned, it can be reattached to the base archwire while never interrupting the Class Ⅱ force. Additional precautions such as stainless steel ligatures, rotation wedges acting as a cushion are recommended to prevent further breakage.

This recovery method was demonstrated in a case of severe canine displacement following the loss of an elastomeric ligature on the mandibular right canine. Realignment using the described procedure was achieved without significantly delaying treatment. Additionally, the chair time and expense of removing and reinserting the Forsus spring was avoided. The authors believe that following failure of a bracket used as a stop for a Forsus spring or the loss of a ligature on this bracket, the use of a crimpable hook and that overlayed nickel titanium archwire can correct any displacement while continuing the Forsus treatment.

Significantly displaced canines are one of the biggest problems I’ve heard clinicians mentioned during Forsus treatment. The best solution is prevention by using stainless steel ligatures, rotation wedges or chain to avoid canine bracket failure. However, the recovery method described is a nice trick to remember because it may allow you to finish on time and avoid the added chair time of removing and reinserting the spring. This Pearls and the clinical pictures can be found in the February, 2013 issue of the JCO.

Long-Term Results of Maxillomandibular Advancement
Surgery in Patients With Obstructive Sleep Apnoea Syndrome

Jaspers GW, Booij A, et al.
Br J Oral Maxillofac Surg 2013;51:e37-e39.

March 21, 2014
Dr. Won-young Park

[초벌원고]

Orthodontists have gotten more involved in the treatment of patient with obstructive sleep apnoea or OSA in the last few years. This is due to the use of  mandibular protrusion appliances but also due to the use of two jaw advancement surgery to enlarge the airway. This maxillomandibular advancement surgery has shown great promise in reducing or eliminating OSA in many patients when studied short-term. But the question still remains whether this improvement is long lasting.

[수정원고]

As a start towards providing long-term evidence, researchers in Netherland recently published the paper in the British journal of oral and maxillofacial surgery called “Long-term results of maxillomandibular advancement surgery in patients with obstructive sleep apnoea syndrome”.

Let me tell you a little bit about this follow-up study and it's results. The subjects for this follow-up were 6 patients that had maxillomandibular advancement surgery for OSA between 2001 and 2003. 5 of 6 were males, and they ranged from 38 to 61 years of age. Each had an 8-mm maxilla advancement and matching mandibular advancement. In order to objectively measure the OSA, sleep studies were done prior to surgery, 6 months after surgery, and then again 8 years after surgery. The Apnoea Hypopnoea Index or AHI and Epworth Sleepiness Scale or ESS were compared among these three time periods.

The initial results were quite dramatic. The initial mean AHI was 36 and it dropped to under 2 at the 6-months follow up. The ESS also showed dramatic reduction in the first 6 months, decreasing from just over 8 to just over 2. When the same 6 subjects were examined  8 years later, there was some change in AHI back up to about 11. But this increased means was almost entirely due to 1 severe individual that returned to an AHI of 43. Even at 43, this represented significant reduction from pre-treatment level. The Mean ESS at 8 years also increased slightly to 3.3

The conclusion was that there was a remarkable improvement and OSA for individual that had maxillomandibular advancement even when studied after 8 years. Although there is the potential for some relapse over time, in this case the change was largely due to one individual who is very severe to start.

This study is obviously limited by it's small sample size, but the long-term results are very encouraging, considering the significant health effect of OSA and the difficulty that many have with the long-term use of CPAP or oral appliances. Maxillomandibular advancement surgery doesn't seem like such an extreme treatment option given the apparent long-term improvements. I would suspect that, as orthodontist, we will see increased demand for help this cases in the future.

If you are interested in this type of collaborate treatment or want to sit down with your local oral and maxillofacial surgeons to discuss orthodontic support for maxillomandibular advancement surgery, this article from April 2013 issue of the British oral and maxillofacial surgery would be a good resource.

Class II Elastics Effective in Correcting Class II Malocclusions

Janson G, Sathler R, et all.
AJO-DO 2013;143:383-392

March 28, 2014
Dr. Tea-woo Kim

[초벌원고]

What are the true effects of Class II elastics in Class II malocclusion treatment and how do they compare with other appliances such as functional appliances? There has been a lot of speculation as to how class II elastics and functional appliances work and what their side effects are? That's why an article titled “Correction of Class II malocclusion with Class II elastics: A systemic review by Guilherme Janson. et al” caught my attention.

[수정원고]

In this article, the authors did extensive search of the literature to identify all articles related to class II　elastics. Only 11 of the 470 articles they identified met the criteria established for the review. Ideally, in a literature review, you would like to identify randomized prospective, controlled studies however if the authors limited their search in this way, it would not have allowed the inclusion of a single article rather than the 11 they identified. Based on these 11 articles, what do the authors conclude? When comparing class II elastics with functional appliances, they concluded that they showed more similarities than differences between the two treatment devices. They noted that the evidence indicates that the well-known orthopedic effects produced by functional appliances do not last over the years and therefore they concluded that was reasonable to state that in the long-term there were no relative differences between treatment effects produced by functional appliances in Class II elastics. Since both protocols have a predominance of dentoalveolar effects as an enduring results. They concluded that on  a long-term basis, class II elastics have similar effects to other methods for class II malocclusion treatment such as fixed functional appliances, contrasting with common belief that these appliances promote greater skeletal effects than do class II elastics.

The bottom line is that this systematic review demonstrated that these differences are diminished by time. Class II elastics are effective in correcting class II malocclusions and their effects are mainly dentoalveolar including lingual tipping, retrusion, and extrusion of maxillary incisors, lingual tipping, and intrusion of mandibular incisors and mesialization and extrusion of mandibular molars. The authors noted that these effects are similar on a long-term basis to those protruded by functional appliances resulting in these two methods being similar when evaluating treatment effectiveness. I must admit that these results did not surprise me. Wayback in a middle 60's, Hugo Lager demonstrated that mandible grows in class II malocclusions whether or not class II elastics and other appliances are used. The only difference is that, if left untreated, class II malocclusions that have significant mandibular growth or not change in a class I occlusion, whereas interfering with the occlusion in almost any way elastics, appliances, whatever, will allow the mandibular growth to be expressed by changing the class II occlusion to class I occlusion.

This study gives great emphasis to the need for prospective controlled trials to address questions like this. You can find this article in the March 2013 issue of American Journal of orthodontics and dentofacial orthopedics.

Esthetic Perception of Black Spaces Between Maxillary Central Incisors by Different Age Groups

Pithon MM, Bastos GW, et al.
Am J Orthod Dentofacial Orthop 2013;143:371-375.

April 4, 2014
Ae-hyun Park

[초벌원고]

It is not unusual to see patients who have completed orthodontic treatment and have black triangles between the maxillary central incisors. These black triangles can be due to accentuated inclination of the incisors , bone loss during treatment, or the triangular shape of the maxillary central incisors. When these black triangle spaces are present, how much do they affect the smile esthetics? Also the different age groups perceived the esthetics of this spaces differently.

[수정원고]

This questions were addressed in the article titled “Esthetic perception of black spaces between maxillary central incisors by different age groups” by Matheus Melo Pithon et al, which appeared in the March, 2013 issue of American journal of Orthodontics and Dentofacial Orthopedics.

In this study, the authors digitally altered an ideal smile to create various degrees of black triangle ranging from 0.5mms to 3.5mms. A group of 150 laypersons were then divided into 3 separate groups by age. Namely 15 to 19 years, 35 to 44 years and 65 to 74 years. The subjects were then asked to evaluate each of the altered smiles using a visual analog scale which ranges 0 to 10, 0 corresponding to “not very attractive" and 10 to “very attractive". The Smile esthetics scores were then statistically analyzed by group. What do you think the results showed?

The black triangles significantly altered the perception of smile esthetics and there was an difference between evaluations of 3 groups. The results indicated that the two younger groups namely 15 to 19 and 35 to 44 years of age correlated with each other and demonstrated increasingly negative perception of smile esthetics as the black triangles became greater. The older group, on the other hand, those ranging from 65 to 74 years of age show no statistical difference between the images with this group awarding high scores to all images. The bottom line of this study is that the younger subjects were able to perceive negative effects of black triangles on smile esthetics but subjects, 65 or older were not.

The authors add no explanation why this difference occurred and being a senior citizen myself, I dare not speculate. Also in evaluating the effect of dark triangles of smile esthetics, it is important to determine if the patient has a high or low smile line. Because if they have low smile line, the black triangle will not usually be apparent. You can find this article in the March, 2013 issue of the American journal of Orthodontics and Dentofacial Orthopedics.

Information-Seeking Behavior of Adolescent Orthodontic Patients

Stephens R, Ryan FS, et al.
Am J Orthod Dentofacial Orthop 2013;143:303-9.

April 11, 2014
Dr. Youn-gyeong Moon

[초벌원고]

How do adolescent orthodontic patients seek information about orthodontic treatment and your practice? Certainly the more you know about how they seek information can help you provide not only better information to them but provide this information in the way that they are likely to use it. An article titled “Information-seeking behavior of adolescent orthodontic patients” by Rachel Stephens, et al. which appeared in March 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics addressed this issue.

[수정원고]

In order to determine how adolescent seek orthodontic information, the authors did a 2-part study. Part 1 consisted of one-on-one interviews with patients who were considering orthodontic treatment and were between the ages of 10 and 16 years. The purpose of this first part of the study was to develop basic themes that would be presented and addressed in a questionnaire that would be given to a larger sample of patients. The 7 themes that emerged from these interviews were information needs, written information, verbal information, World Wide Web, audiovisual information, the media, and information preference.

A questionnaire based on these themes was distributed to 50 patients at the Eastman Dental Hospital’s Orthodontic Department in London, England. I found results of the questionnaires to be very interesting. Basically, this questionnaire asked how patients found information about orthodontics and what they wanted to know about wearing an appliance. 84% of the patients said that they had found information about their future treatment by talking to a family dentist or an orthodontist. Over half the patients also obtained information by talking to friends and parents, and from reading an information leaflet. The surprising thing to me was that only 8% of the patients look to the internet as a source of information. The things that most  patients wanted to know about orthodontic treatment were whether fitting the braces hurts, how to brush their teeth, and whether once the appliances were placed, would it affect their eating or speech.

These results did not surprise me. I found it interesting that only 62% of the patients had read the information leaflet that is routinely sent with their informational letter initially. I thought it was also interesting that although 92% of the patients used the internet for homework and the next most popular activity was social networking at 76% that only 8% of the patients used the internet to look for orthodontic-related information. When the patients were asked to identify their single preferred method for receiving information about orthodontics, the overall preferred method was oral communication, talking to an orthodontist, followed by talking to family members.

The bottom line of this study is that the preferred modes of receiving information were verbal, followed by audiovisual and written. One of the comments about the low percentage of patients using the internet was a concern about the reliability of the information. You can find this article in the March 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

An Overview of Children’s Experiences in Dealing with Cleft Lip and Palate

Sharif MO, Callery P, et al.
Cleft Palate Craniofac J 2013;50:297-304.

April 18, 2014
Dr. Sung-ja Kang

[초벌원고]

I am continually amazed at the treatment outcomes that can be realized for children born with cleft lip and palate. By the time they are eighteen or twenty, the reconstructive surgery, speech therapy, orthodontics, and other adjunctive treatment has largely eliminated the original deformity. But, have you ever considered what is like to be such a child, going through this extensive treatment protocol for most of your childhood and adolescence?

[수정원고]

In an effort to understand things from the child’s perspective, a systematic review was published in the Cleft Palate Craniofacial Journal that we can learn from. The paper is called, “The perspectives of children and young people living with cleft lip and palate: a review of a qualitative literature.”

The authors searched multiple electronic databases for terms related to perspectives of children with clefts. Any qualitative study design which obtained information directly from the patient was included. Initially, 184 potential references were identified, but most studies were not qualitative, did not focus on cleft lip and palate, or obtained information solely from the parents. Only 2 studies met all the inclusion criteria although two additional studies were included that had adult subjects, retrospectively described their experiences as a child.

There were some important findings identified that we should know about. For one, adolescence with the cleft reported bullying and other social issues more frequently than their mothers who tended to focus on the physical condition. Additionally, patients thought that there was a lack of discussion about their cleft within the family and felt uninvolved with the issues related to their treatment. Patients frequently mentioned wanting to talk about the cleft and related bullying, but mothers express concern that would make things worse. Issues related to the speech and the lengths of the time spent at the hospital were also frequently mentioned by the children.

This systemic review indicates that there really is minimal research focused on the perspectives of children and adolescences living with cleft lip and palate, and it highlights the important social aspects. Children want to talk about the cleft and be involved in discussions about their care. This study obviously focuses on patients with cleft lip and palate, but I think many of these findings can be applied to other adolescent patients with esthetic concerns. Frequently, the parents know the exact details they want corrected, but often patients are just worried about fitting in, a great reminder for us about the importance of talking to the child as well as the parents about the chief concerns.

Further details of this systematic review are available in the May 2013 issue of the Cleft Palate Craniofacial Journal.

A 40 Years Follow-up of Dental Arch Dimensions and Incisor Irregularity in Adults

Tsiopas N, Nilner M, et al.
Eur J Orthod. 2013;35:230-5.

May 2, 2014
Sun, Lijun

[초벌원고]

We all know that dental arches don’t remain stable throughout adult life. But now, researchers from Sweden have published some detail information about long-term changes and dental arch dimensions that give us more specific information. This long-term follow-up was published in the April 2013 issue of the European Journal of Orthodontics. The title of the paper is: A 40 Years Follow-up of Dental Arch Dimensions and Incisor Irregularity in Adults. This was a true longitudinal follow-up which means that these subjects were followed for forty years to measure changes. An initial study group of 35 subjects just over 20 years of age were studied between 1949 and 1960. These subjects consisted of 23 dental students and 12 patients who underwent minor treatment at the Royal dental school in Sweden. In 1989, these subjects were recalled to obtain an additional set of study casts. 18 subjects presented for additional models at that time with no history of extractions, orthodontic treatment, or prosthodontic treatment.

[수정원고]

All 18 subjects had study casts available at 3 time points: baseline, after 10 years, and after 40 years, actually a mean of 38.4 years. Overbite, overjet, arch length, intercanine width, intermolar width, arch depth, and Little’s irregularity index were measured in all models and compared over time. Significant dental alveolar changes were seen over the forty years study period. In the maxilla, small decreases of 0.5 to 1 mm were seen in arch length, intercanine width, and arch depth. In the mandible, a decrease in arch length and intercanine width about a millimeter was also seen along with an increase in lower incisor irregularity. No significant changes in malocclusion traits, overbite, or overjet were observed.

This study confirms long-term changes occur in the dental arch dimensions even in non-growing adults. Interestingly, overbite was relatively stable in this study group, although some previous studies have shown long-term changes in overbite during adulthood. Overall, these results seem consistent with my clinical experience and long-term retention studies from the University of Washington. The positive news is that even through long-term changes are to be expected, the magnitude of change in most dimensions was only about 1 mm. These predictable changes must be considered when planning orthodontic retention and speaking with patients about the duration of retention. I have a couple of dentists that I work with that still seem to think that orthodontic treatment ought to be stable in adulthood. This publication from the European Journal of Orthodontics will make a good reference to share with them to reinforce the understanding of life-long changes in the dental arches.

The Prevalence of Approximal Caries in Patients After Fixed Orthodontic Treatment and in Untreated Subjects: A Retrospective, Cross-sectional Study on Bitewing Radiographs

Baumgartner S, Menghini G, et al.
J Orofac Orthop 2013;74:64-72

May, 9, 2014
Dr. Ryu-jin Moon

[초벌원고]

If you compared the sample of patients from your practice who were approximately 15 to 16 years of age and had undergone 2 years of comprehensive orthodontic treatment and compare them with a similar group that did not have treatment. Do you think that your patients would have a higher incidence of interproximal caries?  This question was addressed in a study titled “The prevalence of proximal caries in patients after fixed orthodontic treatment and in untreated subjects: a retrospective, cross-sectional study on bitewing radiographs” by Stefan Baumgartner et al. which appeared in the January 2013 issue of the Journal of orofacial orthopedics.

[수정원고]

In this study, the authors used bitewing radiographs and a standard technique to identify interproximal caries of 104 patients who had completed treatment with maxillary and mandibular edgewise appliances at postgraduate program in the Department of Orthodontics at the University of Zürich Switzerland. These patients comprise the test group. The control group for this study consisted of 111 untreated subjects who were between 15 and 16.25 years of age when radiographs were taken. These subjects came from the same geographic area as the treatment group.

When the researchers compare the average amount of interproximal caries in these two groups, what you think they found? Quiet interestingly, and to me somewhat surprising, they found that the average number of enamel lesions in the test group after fixed orthodontic appliance treatment was lower than the control group. The test group which underwent multi-bracket treatment for slightly over 2 years average 0.57 interproximal lesions versus 1.85 for the control group which was significant difference. I should emphasize that these two groups were matched by age and socioeconomic status.

I was pleasantly surprised to see the results of this study which the authors believe is the first study to evaluate interproximal caries for orthodontic patients. In any case, results of this study clearly contradict the many anecdotal stories about the increase of caries in orthodontic patients. You can find this study in the January 2013 issue of the Journal of orofacial orthopedics.

Precise Movement of Impacted Canines Using Cantilever Springs

Yadav S, Updhyay M, et al.
J Clin Orthod 2013;47;305-13

May, 30, 2014
Dr. Jeong-sil Lee

[초벌원고]

One of the most rewarding yet challenging problems that we routinely treat is the impacted maxillary canine. Because of the distance these teeth must be moved and the challenging initial tooth position, it's difficult to provide the force system that is directed correctly and active over a long range. Although it's often simplest to tie the impacted tooth with an arch wire with elastic thread, this seldom provides most efficient tooth movement. A great alternative for force application is the use of the cantilever springs extending from the molars. This alternative is explained in detail and illustrated clearly in a recent article in the journal of clinical orthodontics.

[수정원고]

The title of article is “Mechanics for treatment of impacted and ectopically erupted maxillary canines.” And we want to review a few of highlights with you. In order to provide the desired force system to an impacted canine , cantilever springs are formed out of .17 X .25 TMA wire. It's important that the end of the cantilever wire prior to activation should lie in the direction the tooth needs to erupt.

Once this free end of the cantilever is ligated to the impacted tooth or attached to  chain, the spring should sit close to the tissue and be comfortable to the patient. The cantilever wire provides for a very low, low deflection curve. So the wire will be active over all long distance without applying excessive pressure to the teeth. The springs also allow the intrusive side effects of the extrusion force to be applied to the molars rather than the incisors, which often causes the incisor intrusion or canting. A transpalatal arch or deactivated hyrax expander is recommended to prevent molar tipping or torquing during eruption of canines. The result of the cantilever arm approach is demonstrated by 3 case reports of successful treatment.

A 13 year-old female with bilateral paralleled canine impactions and a 11 year-old female with right impacted canine and a 12 year-old female buccal ectopic canines. Total treatment time of all cases was between 15 and 18 months, quite impressive for canine impaction cases with nice results achieved. Good keratinized gingiva was present after treatment on all canines as careful attention to the mechanic provided for eruption through attached gingiva.

The authors believed that cantilever springs affectively and efficiently assist with treatment of impacted maxillary canines and they provide force diagrams to help the readers to fully understand the wanted and unwanted forces generated using this approach. The photos in this article are very helpful if you are interested in learning more about cantilever spring design. A useful hint that is obvious in photographs is that the chain attached to the impacted tooth should come directly through the tissue and not through the crestal incision.

If you are interested in seeing this photos or to easy to understand the force diagrams that are mentioned, they are all included in this article that appears in May 2013 issue of the JCO.

Colour stability of aesthetic brackets: ceramic and plastic

Filho HL, Maia LH, et al.
Aust Orthod J 2013;29:13-20

June 13, 2014
Dr. Hye-young Ryu

[초벌원고]

The reason there has been a significant increase in the use of plastic and ceramic brackets is because they are more aesthetic than metal brackets. However, one of the problems with these brackets is that they are susceptible to staining particularly for patients who are coffee, tea or wine drinkers. The plastic or ceramic brackets have a different susceptibility to discolouration to monocrystalline or polycrystalline ceramic brackets have the same susceptibility. In the study titled “Colour stability of aesthetic brackets : ceramic and plastic” by Hibernon Lopes Filho et al., which appeared in the May, 2013 issue of the Australian Orthodontic Journal, the authors address these questions.

[수정원고]

In this laboratory study, the authors evaluated 80 maxillary right central incisor brackets. They evaluated 5 brackets from each of 12 commercial brands of ceramic brackets and 5 brackets from each of the 4 commercial brands of plastic brackets. Each of the brackets was subjected to aging by the irradiation with the Tungsten filament ultraviolet lamp for over 14 hours which was the equivalent of 3 years of average orthodontic treatment. Bracket staining was achieved by the use of 2 solutions of coffee and black tea. A digital spectrophotometer was used to evaluate colour changes before and after the brackets were aged and stained. When they compare the colour changes between the different brackets, what do you think they found?

The bottom line is that the colour stability varied according to the manufacturer and the colour stability cannot be confirmed simply by knowing the type of material and  crystalline composition and structure.

This finding contradicts previous studies that suggested that ceramic brackets presented more colour stability than plastic brackets. They also noted that although there was no significant difference in colour stability between the plastic and ceramic brackets, there was significant variability between the brackets of the same composition or crystalline structure and among commercial brands.

The bottom line of this study is that colour stability cannot be confirmed simply by knowing the type of material and crystalline composition of the brackets. I must admit that prior to reading this study, I would’ve thought the plastic brackets have less colour stability than ceramic brackets, but apparently this is not true. I think it is also important to remember that this was a laboratory study and it would be interesting to see if the same results hold up in a clinical study. You can find this article in the May 2013 issue of the Australian Orthodontic Journal.

Being a Good Leader Will Help Your Orthodontic Practice

June 20, 2014
Dr. Hyun-hee Kim

[초벌원고]

Thanks John for the kind introduction. As the listeners will know we are now picking up on part two of what we started with in the last edition which is standing up to adversity in a volatile world. I only pick up where I left of and ask you the question; what makes a great leader? Many years ago I was traveling at an airport and I was browsing for a small book to read on the flight. I personally prefer to read history but I also like to mix in books that are business related as well. I picked up a book and the inside introduction read; Do you have been elected the CEO of the company? Half the board of directors leave because of your election. And they take half of your employees and the equipment with them and your remaining board members are questioning your capabilities. It's 1860 and you are Abraham Lincoln. What do you do? Well, I was convinced that I needed to buy this book. And this billed for me. The name of the book “Lincoln on leadership” is a book that I read on a yearly basis and recommend it to really everyone. Actually I keep copies in my office and give them out to young people who seem to be the type to benefit from it. Let me give you the bullet points, basically the chapter headings and I’m going to explore the fundamental elements that I gathered from this book.

[수정원고]

The first element is people. Get out of the office and circulate among the troops. In other words, frank communication between you and your employees is vital. Since they often have much more time to communicate with our patients than we do. Encourage rest taking while providing job security. Don’t hold a sword over your employees heads for any small mistakes. Avoid issuing orders. And instead, request, imply or make suggestions. For example; Helen, do that! Or, Helen, you know it’d be nice, it’d be nice to kind of have to be able to do this and that. Which do you think that employee is going to respond to? Well but above all, build strong alliances. But that story will be built as we go.

Next, character. Honesty and integrity are always the best policies. Now we’ve heard this in school in our lives, but think about it a little bit further. Never act out of vengeance or spite. Taking revenge upon someone who has harmed you often not only makes enemies of that person’s friends or even acquaintances. While they may have had a very neutral opinion of what they have observed or heard, have the courage to handle unjust criticism. But when faced with it, do not let it go on too long because the longer unjust criticism goes unanswered, it evolves into the truth.

Next, endeavor. Exercise the strong hand, be decisive. My mother’s first cousin was one of general George Paton’s generals from World War II. You can imagine that he is quite a character. He had retired from Birmingham, Alabama and I had just arrived to Birmingham to begin my orthodontic career. I immediately called on him and before long we became friends with my appension for history that would be natural. He and I would sit up the evenings and he would go through his war college slides and relate to me the strategies and the trials in the battles. One might have stopped and asked him the question; general Mason, what was it like to be in the position of having to make a decision in which as many as half or even two thirds of the twenty five thousand men under your command lives or dies? I personally could not imagine a burden so great. General Mason, he was a West Point graduate, was clear-eyed and cool, and turned and looked at me with a look that I won’t ever forget and replied. You make a decision. In World War II I had three choices when given a set of circumstances. Make a decision. It might be the right one, or it might be the wrong one. The main thing is that neither you nor the enemy knows whether the decision you’ve made is the right one or the wrong one. Whatever direction you take off in with your army, he has to decide; now why is he going that way? Do I need to react to it? Which then gives the enemy a pause and delays his next decision and enforces him to react and expand resources to encounter your decision. If you make the right decision you win. If you make the wrong decision you have a bigger test ahead. But if you do nothing, then the enemy knows where you are and have best chance of defeating you. Again a lesson I won’t forget.

Next, never lead by being led. Your employees here thinks from patients that patients would never say to you. We all have that experience, but this is information that is important to bubble up from your employees and if the goals of all the employees of the practice are the same, we can then out set the goals and be results oriented.

Finally, keep searching for your Grant. When Ulysses Grant was chosen by Abraham Lincoln to command the entire US army in the civil war many of his advisors were simply appalled. Grant, even though he was a West Point graduate had been mustered out of the army prior to the outbreak of the civil war for alcohol abuse and generally slovenly and unkept appearance he did not look like a commander. When Lincoln named him the head of his army, his advisors said; Look at him he has cigar in his mouth all the time his uniforms are unclean his boots are muddy he simply does not look like a general. Lincoln’s answer was clear and concise. He wins battles. Well, I think that’s what we all are looking for in an employee. It’s not necessarily most physically attractive one but the ones that can relate to our patients, perform, and win battles for us.

Next, communication. For each of vision continually reaffirm it. Let us use the Apple marketing philosophies for example taken from Steve Jobs recent biography. Steve Jobs when he created the Apple computer recall; this was not about processors and memory. It was about creativity. It was designed to celebrate not what the computers could do, but what creative people could do with computers. What does that have to do with orthodontists? His Jobs also stated that Michelangelo not only was a great artistic talent, but he also knew how to carve his stone. In my interpretation unless Michelangelo did not understand the physical principles of a stone he was selecting for his statues, the working properties or timeless nature would have hindered his overall success. To overstate the case, he did not use hand stone because it would crumble in the process of carving delicate features. No over to hold up perfectly for centuries. We as orthodontists understand the science very well. We just strive to liberate our artistic subside. We were all given a block of wax when we started dental school and given the simple instruction; make it look like a tooth. We were given very little instruction on how to do that but in the end most did pretty well. Some incisors look like a police whistle for sure, but many were truly works of art. I firmly believe that in our case, it is not the brackets or the wires that are ultimately most important. It is us, what we know and what we can see as the treatment goal and how to get there is the ultimate conclusion. What sort of wake are you leaving? As I have said earlier in this presentation, we have arrived at the enviable position in our community because of those who have gone before, in the wake that they have left behind. This wake and this is like a wake of a boat, you know, to paint the picture in your mind, it’s not just the orthodontic practice but our contribution to the community, and the lives of our patients.

Buccally Displaced Canines More Prevalent With Certain Dentofacial Characteristics

Mucedero M, Ricchiuti MR, et al.
Eur J Orthod 2013;35:305-9

June 27, 2014
Dr. Zhang, Fan

In the past, we reviewed several articles investigating individuals with palatally displaced canines, and learn that they are associated with tooth agenesis, reduced tooth size, other ectopic teeth, and hypodivergent facial patterns. Although buccally displaced canines have been associated with crowding, little evidence exists relating them to other dentofacial characteristics.

To help complete our knowledge base in this area, researchers in Italy recently published the results of their study called prevalence rate and dental skeletal features associated with buccally displaced maxillary canines. This paper appeared in the June 2013 issue of the European journal of orthodontics and the study was designed to compare dentofacial features of patients exhibiting buccally displaced canines with those patients having normal canine eruption. More specifically, this was an observational study involving 852 subjects, 8 to 14 years of ages, seeking orthodontic treatment at the university of Rome.

Subjects with craniofacial anomalies, cleft lip and palate, traumatic injuries, or cysts were excluded. From the study sample, 252 subjects were randomly selected to serve as the control group. The remaining patients were examined for the presence of buccually displaced canines and included in the study group if the canine was overlapping the lateral incisor in the panoramic radiograph, and periapical radiographs confirmed a buccal position. Cephalometric measurements were recorded for both control and buccally displaced canines groups to analyze sagittal relationships using the ANB angle and vertical skeletal relationships using SN to mandibular plane. Intercanine width using the primary canines, intermolar width, and crowding were measured from the dental casts.

There are two important results that I’d like to remember. The first was the prevalence rate which turned out to be 3% of this sample of 49 subjects. Interestingly, they appeared equally in males and females, and unilateral cases were seen twice as frequently as bilateral cases. The second thing I want you to remember is the other characteristics that were associated with buccally displaced canines. These are hyperdivergent facial patterns which were seen more commonly in cases with buccally displaced canines, decreased intercanine width and increased crowding. The intercanine width is almost 4mm less and crowding 4 mm more in the buccally displaced canine group.

What we’ve all learned from this paper is that buccally displaced canines are relatively rare, only about 3% of orthodontic patients, and they are associated with a hyperdivergent vertical growth pattern, increased maxillary crowding, and decreased intercanine width. These would be good information to share with the dentists in your area so they can recognize this problem early and get it to you properly for comprehensive treatment. If you want to share copies, you can locate this paper in the June 2013 issue of the European journal of orthodontics.

copies, you can locate this paper in the June 2013 issue of the European journal of orthodontics.

Three-dimensional evaluation of facial asymmetry in association with unilateral functional crossbite in the primary, early, and late mixed dentition phases

Jamina P, Giuseppe P, et al.
Angle Orthod. 2013;83:253-8

July 4th, 2014
Jiang, Ting ting

[초벌원고]

When do you correct posterior crossbite in children? Today there's an emphasis for one stage rather than two stages of orthodontic treatment. So if a patient at 8 years of age has a posterior crossbite and a crowded dentition, you know you would probably treat the patient with complete orthodontic appliances eventually. Should you do two phases of treatment that is palatal expansion to correct the crossbite followed by an observation period, and then complete orthodontic therapy? Or could you simply wait until all permanent teeth have erupted and then correct the crossbite and do the tooth alignment in one phase? Are there any advantages for one approach over the other？One advantage to waiting would be that the patient would only have to wear  appliances one time. But could there be an advantage in terms of facial asymmetry of both a mandible and a maxilla if you corrected the crossbite earlier in the mixed dentition? That question was raised in the study that was published in the March 2013 issue of the Angle Orthodontist. I thought this would be an interesting study for us to review. The title of the article is "Three-dimensional evaluation of facial asymmetry in association with unilateral functional crossbite in the primary, early, and late mixed dentition phases". The study comes out of Slovenia, and the research was performed at the department of Orthodontics at the University of Ljubljana. The lead author is Dr Primozic.

[수정원고]

The purpose of this study was to compare the degree of facial asymmetry that was recorded using three dimensional laser scanning methodology in growing subjects according to their phase of dentition. In order to accomplish this objective, the authors assembled a group of over two hundred Caucasian individuals. About a third of these had unilateral functional crossbites with a shift of the mandible. Two thirds of the sample did not have a malocclusion. The age ranges of these individuals were between 4 and 12 years of age, so they were in different stages of dentition. The authors divided the sample according to their stage of dentition as to primary, early to intermediate mixed dentition, and late mixed dentition. In order to determine facial asymmetry, the authors used three dimensional laser scanning methodology which created a color mapping of the face, which allowed the authors to recognize symmetry and asymmetry of the faces of these children. Then they measured the asymmetry quantitatively as average distances in millimeters between mirrored images on the right and left sides of the faced.

I think you get the idea of this experiment, the source of rather novel methodology. What did these researchers find? Question No.1: Do children with unilateral functional crossbite have facial asymmetry? And the answer to that question is yes, these researchers showed that at all dental stages - primary, intermediate mixed, and late mixed dentitions there was greater facial asymmetry in children with malocclusion than those that did not have a malocclusion. Question No.2: Where was the asymmetry the greatest? In this study the greatest part of the asymmetry was in the lower part of the face, which would make sense because these children all have a lateral mandibular shift. Question No.3: Did this asymmetry affect the middle part of the face or the maxilla? The answer to that question is also yes. During the transition from the primary to the mixed dentition the authors noted that the middle part of the face became clinically and statistically more asymmetric with time indicating that the change in mandibular position was initiating changes in the maxilla. So how should we apply this information? Remember my original question to you? Should you treat a crossbite early or wait and treat it later? Based upon the results of this study, it seems that if a crossbite persists, not only is the mandibular position affected, but eventually there can be an impact and an effect on the maxilla. This occurs during the transition from the primary to the mixed dentition. So in order to avoid changes in the maxilla based upon the results of this study, it would seem that earlier correction of the crossbite would prevent compensatory symmetries from being created in the maxilla. If you’d like to read this study, you can find it in the March, 2013 issue of the Angle Orthodontist.

Remove Impacted Teeth With Orthodontic Techniques

Ma ZG, Xie QY et al.
J Oral Maxillofac Surg 2013;71:1309-17.
                                                                 

July 11, 2014
Dr. Ha-yeon Park

[초벌원고]

One very common clinical scenario for all of us is the patient who presents for lower third molar removal who is at risk of nerve entry. Often these are older patients who are noted on panorex to have predictable findings such as loss of cortical margins as the nerve passes over the root, deflection of the canal, or darkening of the root. Certainly the prospective creating iatrogenic injury when patients are usually minimally symptomatic is of concern. Various alternative techniques for removal of these teeth have been proposed and implemented over the years. These include coronectomy in which the clinical crown is removed hoping for eventual migration of the tooth upwards away from the canal. Migration of third molars using orthodontic techniques has been previously reported and has used traditional spring mechanisms as well as skeletal anchorage techniques.

[수정원고]

This article entitled “An orthodontic technique for minimally invasive extraction of impacted lower third molars” appeared in the journal of oral maxillofacial surgery. It was a technique article reviewing eight patients ranging in age from 25 to 39 who were noted to have third molars needing removal, but with evidence radiographically of an intimate relationship to the canal. This proximity was verified by cone beam imaging. There were a variety of impactions: two horizontal, four mesioangular, and two vertical. The authors used two types of appliances depending on the position of the tooth and these are more easily reviewed in the manuscript than by having me try to explain their design here. They were, however, very simple orthodontic mechanisms that did not utilize skeletal anchorage. Surgery to expose the disto-occlusal surface of the crown was done and the appliance was bonded in place. All eight patients had successful migration of the tooth superiorly and distally and eventual simple extraction. No cases of paresthesia occurred. I think it’s important that we keep these types of alternative treatments in the back of our minds when these types of impactions are in need of removal. It gives us a chance to think out of the box in a novel way that may be very beneficial to our patients.

Electronic More Effective Than Manual Toothbrushes
for Removing Plaque

Erbe C, Klukowska M, et al.
Am J Orthod Dentofacial Orthop 2013;143:760-766.

September 12, 2014
Dr. Ha-yeon Park

[초벌원고]

Every orthodontist recognizes the importance of good oral hygiene to achieve an excellent treatment result. When giving oral hygiene instructions to a specific patient, it is not uncommon for the patient to ask whether it is better to use an electronic tooth brush versus a manual brush. What do you tell your patients? A study titled ������Efficacy of 3 toothbrush treatments on plaque removal in orthodontic patients assessed with digital plaque imaging: A randomized controlled trial������by Christina Erbe et al. addressed this question.

[수정원고]

In this study, the authors subdivided 45 patients into 3 groups of 15 each. All patients for undergoing orthodontic treatment with full bonded appliances will be given a specific regimen for brushing their teeth with either an oscillating-rotating electric toothbrush with a specially designed orthodontic brush head, the same toothbrush handle with a regular brush head, and a manual toothbrush.

The patients were scheduled to brush for 2 minutes every 5 days for total of 6 visits. And that each visit a digital plaque imaging analysis(DPIA) was done prior to and after brushing. Changes in plaque accumulation have traditionally been measured by clinical observations which have inherited limitations. More recently, objective area-based image techniques have been developed that offer advantages over more traditional measurement method. One of these techniques is the digital plaque imaging analysis which was used in this study. When the authors statistically evaluated the effectiveness of plaque removal with the 3 different toothbrushes, what do you think they found? First of all, they found that both electronic tooth brushes were more effective than the manual toothbrush. When the two different types of electronic toothbrushes were compared, plaque removal with an electronic toothbrush with orthodontic brush head was superior to the regular brush head. So now, if your patients ask whether they should use an electronic toothbrush, you can tell them yes and also tell them that there is an electronic toothbrush specifically designed for orthodontic patients that is more effective than the traditional electronic toothbrush. You can find this article in the June, 2013 issue of American journal of orthodontics and dentofacial orthopedics.

Oral Hygiene Still a Concern With Clear Aligners

Moshiri M. Eckhart JE, et al.
J Clin Orthod 2013;47:494-498.

September 19, 2014
Dr. Won-young Park

[초벌원고]

When I discuss the option of clear aligners for orthodontic treatment, I often mention better oral hygiene as a benefit because the aligners can be removed for brushing and flossing. However, they also limit the flow of saliva to teeth for natural buffering and cleansing. To illustrate how poor oral hygiene can still be a significant concern with clear aligners, several authors collaborated on an article for the August 2013 issue of JCO that demonstrates the potential problems.

[수정원고]

The 4 cases chosen for this article were all treated with Invisalign® and were selected based on observed decalcification associated with poor oral hygiene. In the first case, a 14-year-old male was given 5 clear aligners to wear over the course of 10 weeks. When he returned, he admitted to not brushing since his last visit and had significant decalcification around his attachments and molar cusp tips. And the second case, a teenage male returned after 4 months of aligner wear with caries on the incisal edges and cusp tips of his teeth. He admitted to eating with his aligners in place consuming soda without removing the trays. The third case involved a 47-year-old female who didn’t want to remove her upper tray due to a missing left central incisor. After 8 months of treatment no decalcification was noted, but significant decalcification was seen during the second year of treatment. Finally, a 33-year-old female showed significant decalcification on cusp tips and incisor edges after 11 months of treatment. She only removed her trays once per day for brushing.

What this series of cases demonstrates is that even though clear aligners do allow for easier dental hygiene since they are removable, proper hygiene still has to be done. These patients should still be closely observed and carefully instructed on the importance of removing aligners from years and when consuming sugary drinks. The authors gives several specific recommendations for patients with aligners such as; Never eat with the aligners in place, supplement night time brushing with fluoride rinses, and use a “toothpaste slurry” rinse when brushing. I planned to use the clinical photographs in this article for communication with patients selecting aligners to help them understand the importance of proper hygiene. It will also be a good article to share with referring dentists so that they reinforce proper care instructions as they see these patients in treatment. I wasn’t surprised about the 2 adolescent males that were presented, but the 2 older females were unexpected. This is generally a group that I don't expect hygiene concerns and all be more careful with those that have a pontic as part of their aligners since there is more reluctance to eat without it. To find the photos for use as communications tool, look in the August 2013 issue of the Journal of Clinical Orthodontics for the article called “Consequences of poor oral hygiene during clear aligner therapy”.

Mandibular Advancement Relapse Evaluated With CBCT

Franco AA, Cervidanes LHS, et al.
J Oral Maxillofac Surg 2013;71:1588-1597.

September 26, 2014
Dr. Tae-woo Kim

[초벌원고]

Suppose that you are preparing to treat an adult patient, who would ideally be treated with a mandibular advancement surgical procedure. And the patient asks, “How stable is this surgery going to be? And are there any surface remodelling changes that occur following the procedure?” How would you answer that question? The study by Alexander Franco and co-authors in September 2013, Journal of Oral and Maxillofacial Surgery examined those questions.

[수정원고]

Mandibular advancement orthognathic surgery has been shown to be a relatively stable procedure when assessed with 2 dimensional radiographs. The occurrence of short term soft tissue and hard tissue changes following surgery have been identified utilizing cone beam computed tomography (CBCT) in earlier studies. What researchers in this paper wanted to assess was a longer term 3 dimensional changes and the positions of the condyles, rami, and chin following mandibular advancement surgery. This was a prospective study of  27 orthodontic patients with an average age of 26.7 years who received mandibular advancement surgery. 40% of the patients also received the genioplasty with the mandibular advancement. All of the patients had a skeletal class 2 malocclusion and a normal or deep overbite. The advancement surgeries were all performed with bilateral sagittal split osteotomy and rigid fixation with screws and plates were employed for all patients. CBCT scans will be obtained prior to surgery, 1 year after-surgery, and 3 years after-surgery.

The CBCT images were superimposed on the presurgical cranial base. A software program was then employed to analyze any surface changes between the 3D images. Any measurable differences will visually displayed and quantified using 3 dimensional color maps. And what did these researchers find? The anterior and inferior surfaces of the chin typically rotated downward and backward 2mm or more, 1 to 3 years following surgery. Most of the measured anatomic areas and the overbite and overjet had very small changes of less than 0.5mm. The mean rami and condylar surface changes were also less than 0.5mm.     The authors concluded that mandibular advancement surgery with rigid fixation is generally stable on evaluation at 3 years. CBCT scans indicated that there are small changes of less than 0.5mm to the rami, condyles, and chin. About 20% of the patients will have 2 to 4mm changes to the chin’s horizontal and vertical position. Approximately 20% of the subjects had condylar displacements or bone remodelling on the anterior surface of the condyle. These 3D studies supported 2D studies that report the relative stability of mandibular advancement surgery with rigid fixation. The 3D superimposition shed light on the s

Simple Method to Extrude Fractured Anterior Teeth
With Fixed Appliances

V. A. Kumar, A. V. Arun, S. A. Kumar, et al.
J Clin Orthod 2013;10:603-610.

October 10, 2014
Dr. Sei-won Jun

[초벌원고]

As an orthodontist, you may be asked by a dental colleague to extrude a fractured incisor to allow better access for a healthy and esthetic restoration of the tooth. Typically, I see people place brackets on each side of the fractured incisor and use a flexible wire to accomplish this extrusive movement. This can be fast and easy but may permit unwanted movement to the adjacent teeth. A different approach to rapid extrusion of fractured incisors was presented in the October 2013 issue of the JCO, and I think you should be aware of it. The article that presents the technique is called "A fixed extrusion appliance for fractured anterior teeth", and I will try to help you visualize the mechanics these authors suggest. Edgewise brackets are bonded to the adjacent supporting teeth in the arch while the fractured tooth is bonded with a vertical tube. A 016x022 stainless steel archwire is bent to fit passively in the supporting brackets, and then stepped vertically to sit 6 to 8 mm gingival to the vertical tube. A short length of round wire is soldered to the center of this vertical offset segment, such that it runs vertically through the center of resistance of the fractured tooth. Open coil spring is placed on the round wire, and the wire is inserted through the vertical tube on the fractured tooth. After ligating the other brackets, a horizontal stop can be placed on the round wire extending through to tube, so that the amount of extrusion can be precisely controlled. The results of this technique are demonstrated with three cases showing extrusion of a fractured incisor to a location where an ideal crown can be fabricated. According to the authors, the appliance was tolerated well by all patients and required minimal cooperation. The open-coil spring help maintain a constant light extrusion force that didn't required reactivation and resulted in extrusion of about 1.5 mm per week. The authors used a Begg bracket for the vertical tube, but any bondable tube position vertically should work as well. This method does have a wire bent into the vestibule, which may be difficult to position comfortably. However, I do like the idea of the open-coil to extrude the root with a constant force to exactly the desired position. This method can help prevent the lateral forces and unwanted side-effects sometimes seen when using light nickel-titanium wires. The biggest challenge maybe the esthetic compromise of this appliance during the extrusion process. As it's typical with articles in the Journal of Clinical Orthodontics, this technique is well-documented with photographs to help with understanding and visualization. If you want a copy of the whole article to better understand the technique I've described or to used with a colleague to explain how simple orthodontics can greatly enhance restorative success, you can find it in the October 2013 issue.

[수정원고]

Combined Surgical Orthodontic Tx for Class Ⅲ Skeletal Problems
Appears Relatively Stable

de Haan I F, Ciesielski R. et al.
J of Orofacial Orthop 2013;74:362-369.

October 17, 2014
Dr. Jung-sil Lee

[초벌원고]

If you have been in practice for reasonable amount of time, I suspect that you have treated Class Ⅲ adult patients with combined surgical orthodontic treatment. How stable is Class Ⅲ combined surgical orthodontic treatment? Would the answer be different, if you are looking at Mandibular reduction surgery versus Maxillary advancement surgery. In an article titled “Evaluation of relapse after orthodontic therapy combined with orthognathic surgery in the treatment of skeletal class III” by Inken Friederike de Haan et al. which appeared in the september, 2013 issue of the Journal of Oral-facial Orthopedics attempted to answer this question.

[수정원고]

In this study the authors evaluated a total of 30 patients who had undergone orthodontic treatment combined with orthognathic surgery. To be included in the sample, the patients had to be treated with mandibular setback surgery alone or combined with maxillary advancement. Rigid fixation was used on all patients and lateral cephalometic radiographs were obtained before surgery after a maximum of 3 days post-op and after 6 to 12 months. The surgeries were performed at the center of dental oral and maxillofacial medicine university hospital of Schleswig-Holstein in Kiel, Germany.

In the conclusion of their article, the authors stated that stable treatment outcomes were observed in the vast majority of their treated patients during follow up examinations and that maxillary advancement procedures were found to be less susceptible to relapse. They also concluded that mandibular setback distances correlated positively with the degree of the relapse, that is, the greater the mandibular reduction, the greater the likelihood of relapse. They also noted that there was no statistically significant differences when procedures conducted in both jaws were evaluated versus in the lower jaw only and that the extent of maxillary advancement did not related to amount of relapse.

I am reviewing this article for this month’s program, because I think it's a good example of why it is necessary to read an article in its entirety as opposed to just looking at the conclusion section.

The sample for this study was based on a total of 30 patients, and only 6 of the 30 patients had only mandibular reduction surgery which obviously is not a large enough sample to make conclusions about this procedure. When the authors evaluated stability of surgical procedures, they determine that clinically relevant relapse was relapse by greater than 2 mm or 2°, which was observed in 21% of the patients treated with maxillary surgery and 27% of those who underwent mandibular surgery which they felt indicated that the maxillary advancement procedures are more stable. Based on this state alone, it would indicate that approximately 1 in 3 patients who underwent only mandibular reduction surgery would have clinically relevant relapse which in my mind did not justify their conclusion that stable treatment outcomes were observed in the vast majority of their treated patients during follow up examinations.

This article is a good example of why randomized controlled trials are necessary to make scientifically based conclusions for various research questions. For my personal experience, I believe that a best majority of Class Ⅲ combined surgical orthodontic procedures are stable and that maxillary advancement appears to be more stable than mandibular reduction. So the conclusions of this article appear to me to be reasonable. However, they didn't appear to be based on good research protocol. You can find this article in the Journal of Oral-facial Orthopedics.

Open vs Closed Surgical Technique for Palatally Impacted Maxillary Canines

Parkin NA, Milner RS, et al.
Am J Orthod Dentofacial Orthop 2013;144:176-184.

October, 24, 2014
Dr. Youn-gyeong Moon

[초벌원고]

When you have patients present to you with palatally impacted canines, how do you have them exposed? Do you use an open or closed surgical technique? Is one or the other of these two techniques better related to periodontal health? This question is addressed in an article titled ������Periodontal health of palatally displaced canines treated with open or closed surgical techniques: A multicenter, randomized controlled trial by Nicola A. Parkin et al. which appeared in the August, 2013 issue of the American Journal of Orthodontics and Dentofacial orthopedics.

[수정원고]

The patients for this study which was a multicenter, randomized controlled trial were obtained in 3 hospitals in the United Kingdom. The sample for this study consisted of 62 patients who had unilaterally impacted maxillary canines. The sample was divided into 2 groups : one of which a closed surgical exposure and the other open surgical exposure. Periodontal measurements were recorded at baseline and 3 months after removal of fixed appliances and differences in periodontal attachment level, gingival recession, and clinical attachment levels were calculated. The authors also measured the contralateral maxillary canines which were not impacted. When they compared two surgical techniques, what do you think they found? There was no difference in periodontal impact when closed and open surgical techniques were compared and surgical impact on maxillary impacted canines is so small that it is unlikely to influence the prognosis of a tooth in the long term in most patients.

I was surprised to see that there was no difference because recently there have been some studies and presentations that have suggested that the closed technique is more favorable to periodontal health. This study is a good example of the benefit of randomized controlled trials and the only concern I have is that it was multicenter study which always makes it difficult to standardize research procedures. You can find this study in the August, 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Relationship Between Self-Perceived Oral Health, History of Abuse

Kvist T, Annerback EM, et al.
Eur J Oral Sci 2013;121:594-599.

November 7, 2014
Dr. Sun, Lijun

[초벌원고]

An article in the December 2013 issue of the European Journal of Oral Sciences has some important information for us that we sometimes choose to ignore. This article is called “Association between adolescents, self-perceived oral health and self-reported experience of abuse”. Orthodontists are frequently interacting with children and adolescents, and therefore in a position to identify the child abuse. Common findings related to abuse may include fractures, contusions, bruises, burns, untreated caries, and behavioral issues. The purpose of this population based survey was to examine the relationship between reported exposure to various types of child abuse and self-perceived oral health.

[수정원고]

Over 7000 Swedish students in Sodermanland County were invited to participate. These were all grade 9 compulsory school and second-year high-school students. Amazingly, nearly 6000 (82%) students responded. Data was gathered from questionnaire completed by students in the classroom focusing on sociodemographic variables, abuse, and self-perceived oral health. Responses were kept anonymous, but resources on counseling opportunities were given to all students because of the sensitive nature of the questions.

Here is what they found that we need to know. Overall, 21% of students reported some history of childhood abuse, including physical abuse, intimate partner violence, forced sex, or bullying. Most respondents reported very good or good oral health, with only 3% participants rating their oral health as poor or very poor. Students with an unemployed parent or separated parents were twice as likely to report poor oral health. Respondents reporting a history of child abuse were between 2 and 15 times more likely to report poor oral health, with weekly bully showing the most significant effects on reported oral health. Half of the students who reported very poor oral health had a history of violence between adults in the family and reported being hit by a parent or caregiver.

Comparison of maxillary arch dimensional changes with passive and active self-ligation and conventional brackets in the permanent dentition: A multicenter, randomized control trial

Fleming PS, Lee RT, et al.
AJODO 2013;144:185-193.

November 21, 2014
Dr. Zhang, Fan

[초벌원고]

Self-ligating brackets have increased popularity as an alternative to traditional brackets for comprehensive orthodontic treatment. A number of claims have been made for self-ligating brackets, including that they are more efficient for initial arch alignment. A study titled, "Comparison of maxillary arch dimensional changes with passive and active self-ligation and conventional brackets in the permanent dentition: A multicenter, randomized control trial" by Padhraig S. Fleming. et al which appeared in the August 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics addressed this question.

[수정원고]

In this study, 96 patients aged at 16 and above were included in a multicenter three group parallel randomized trial. The subject was subdivided into three groups, one of which at maxilla교 arch bonded with passive self-ligating bracket, the second with active self-ligating system, and the third with conventional bracket system. A standardized for correction of arch wire changes was used for each patient and study cast and lateral cephalomatric radiographs were used to evaluate arch width changes at the canines , premolars and molars, and changes at axial inclination of the long axis of the maxillary incisors relative to the maxilla plane and the first molars. Arch wires were left in place for minimum of 34 weeks.

What do you think the authors’ found when they evaluated three systems? The bottom line is there are no differences at maxilla arch dimensional changes or molar and incisor inclination changes found after alignment with passive self-ligating brackets and active self-ligating brackets or conventional brackets. This study is a good example of the advantage of using randomizing control trails to evaluate claims made by manufactures or individual for specific products or treatment philosophies. The bottom line is that there may be a number of different reasons to use self-ligating brackets versus conventional brackets. However, efficiency in arch alignment is not one of them. You can find this article in the August 2013 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Deep Bite Correction With Intrusion in Adults Is Relatively Stable Long-Term

Varlik SK, Alpakan ÖO, et al.
Am J Orthod Dentofacial Orthop 2013;144:414-419.

November 28, 2014
Dr. Jiang, Tingting

[초벌원고]

I’m sure you have treated many adults ClassⅡ division 1 patients by extracting only maxillary premolars. These patients often have a mandibular deep bite. My question to you is how do you usually level the mandibular arch in these deep bite patients, and if you use a mandibular utility arch to intrude the incisors, is this intrusion stable long term in adults?

[수정원고]

A study titled “Deep bite correction with incisor intrusion in adults: A long-term cephalometric study” by Selin Kale Varlik et al. which appears in the September 2013 issue of the American Journal Orthodontics and Dentofacial Orthopedics addressed this question. The purpose of this study was to investigate the long term stability of deep bite correction with mandibular incisors intrusion using utility arches in adult patients. The sample for this study consisted of 31 adult patients who had Class Ⅱ division 1 malocclusion that were treated in one phase with maxillary first premolar extraction. Mandibular utility arches were used to intrude the incisors. Lateral cephalometric radiograph were taken pre-treatment, post treatment and five years post retention. What do you think the authors found when they examining these records? Were the mandibular incisors significantly intruded? And if so, were they stable? The bottom line is that the mandibular incisors were significantly intruded in average of 2.6mm with only 0.8mm of molar extrusion. After five years it was significant but clinically unimportant relapse of an average of 0.8mm which corresponded to approximately 30% of the totally intrusion amount. Based on these results the authors concluded that deep bite treatment with mandibular incisors retrusion with utility arches is effective, and appears to be stable in non-growing patients.

I should point out that the samples for this study consisted of non-growing patients with normal vertical dimensions. I mention this because I can think of two situations in which you would not want to level the mandibular arch with incisors intrusion. The first would be an adult ClassⅢ patients with deep bites and anterior facial over closure that you are treating with orthodontics alone. In these patients the goal is to rotate the mandible clockwise to improve the dental deep bite, facial over closure and chin protrusion. In these patients who usually have significant step up in the mandibular arch anterior to the first premolars, it is best to level the posterior segmentally extruding primarily first premolar area, thereby rotating the mandible downward and backward.

The second situation is in surgical mandibular advancement patients who have anterior facial over closure for whom you would like to advance the mandible both forward and downward using a tripod mandibular advancement. I was happy to see that there was minimal long term relapse in the cases that the authors examined and I don’t know what your guess was. But I suspected it might have been greater. You can find this article in the September 2013 issue of the American Journal Orthodontics and Dentofacial Orthopedics.

Tongue Spurs Are Effective in Closing Anterior Open Bites

Meyer-Marcotty p, Kochel J, et al
Aust Orthod J 2013;29:145-152

                                                          Dec 5, 2014
                                                         Dr. Hye-young Ryu

[초벌원고]

In the case report article that I reviewed in last month's program involving the treatment of an open bite, I suggested that the authors might have considered the use of tongue spur therapy prior to deciding on the need for surgical treatment to correct the open bite. Have you ever used tongue spurs to correct the open bite?  If you have, were they effective? If you haven't used tongue spurs what was the reason that you decided not to use them? Did you think would not be effective or possibly not tolerated by patients due to their sharp piece? A study titled “The impact of spur therapy in dentoalveolar openbite” by Philipp Meyer-Marcotty et al. which appeared in the November 2013 issue of the Australian orthodontic journal addressed these questions.

[수정원고]

In this study the authors evaluated 31 patients who average 13.3 years of age and received tongue spur therapy for the correction of their anterior open bites. The authors used a powerful bar from maxillary first molar to maxillary first molar that had pointed spurs at a 45° downward angle from the occlusal plane distal to the maxillary incisors. Plaster cast and lateral cephalometric radiographs were taken prior to treatment and immediately after tongue spur therapy to evaluate dental and skeletal changes. The tongue spurs were left in place for an average of eight months during which no other orthodontic therapy was initiated. What did the authors find when they evaluated the changes that had occurred? The bottom line is that the use of tongue spurs resulted in the correction of the open bite in all patients. This is the kind of study that I like because you don't have to do any powerful or robust whatever term you want to add to statistics to determine what happened since the appliance worked in 100% of the cases. Additionally the authors noticed that no patient treated with palatal spurs had the appliance removed early nor were injuries to the tongue or the oral mucosa encountered. Previous research has also shown that these appliances have no negative psychological effects on patients. I should also note that a primary cause of anterior open bites is a resting tongue habit which appears as a rectangular opening mesial to the canines and a picture of a patient with a resting tongue habit is demonstrated in this article. I should also know the research has shown that tongue thrusting habits are not a cause of anterior open bites but rather an accommodation to the oral environment that is excessive overjet. When the overjet is corrected, tongue thrusting will discontinue. Results of this article strongly support the work of Dr. Roberto Justus -Mexico City- who has demonstrated numerous cases of significant open bite closure by simply using tongue spurs. You can find this article in the November 2013 issue of the Australian orthodontic journal.

Quantifying Subtle Changes In Condylar Morphology Using Regional Superimpositions

Schilling J, Gomes LC ,et al
Dentomaxillofac Radiol 2013;43:20130273 

December, 12, 2014
Dr. Ryu-Jin Moon

[초벌원고]

How did you go about comparing mechanical CBCT images of one of your patients from before and after treatment to determine whether any morphologic changes occur? CBCT offers improved visualization of bony changes of the temporomandibular joint compared to traditional 2-dimensional images, but quantification of those changes is difficult due to the complexity of 3-D superpositions. Some idea of what may be in future was published recently in the journal dentomaxillofacial radiology in a paper called regional 3-D superposition to assess temporomandibular joint condylar morphology. Let me tell you about how these authors went about validating a procedure to objectively compare condylar morphology.

[수정원고]

36 subjects with previously required CBCT scans were analyzed. 12 patients with a clinical diagnosis of osteoarthritis were compared to 12 similarly aged healthy control subjects. An additional 12 patients provided a longitudinal sample having CD CT scans required prior to jaw surgery, immediately after surgery, and one year after jaw surgery. All scans were reformatted to a standardized voxel size of 0.5 mm and surface models were constructed using a semi automatic and manual segmentation method. For comparison between control subjects and osteoarthritis patients, significant variability in condylar morphology existed, requiring a landmark-based superposition method. The coordinate system was standardized using 25 points on each surface model. An average mesh for each sample group was created, and 3D point-wise subtraction was performed to calculate surface differences. In the longitudinal group, voxel based registrations were possible using the condyles as regions of interest. Surface changes were again calculated between various time points. Using this method, significant differences between the condyles in control subjects and in patients with osteoarthritis were seen, especially bone loss of the lateral and medial poles. The authors also demonstrated that longitudinal voxel based registration could be reliably performed with small mean interobserver differences. This registration allowed visualization and quantification of bony changes in cases showing marked resorption of the condyle following orthognathic surgery.

What this means to us is that techniques using open-source software to superimpo se CBCT images are reliable for longitudinal superimpositions and across-subject registrations. The challenges that these techniques are still labor-intensive, but I think this paper is important in showing that methods of superposing CBCT images are being developed and showing good results. These methods improve each year and, hopefully, will soon be available for quick and easy comparisons in clinical practice. If you're interested in performing these comparisons on your own the software used to solve open-source and you can consult the article for details. Check it out in the journal dentomaxillofacial radiology.

Basic training requirements for the use of dental CBCT by dentists: a position paper prepared by the Eurpean Academy of DentomaxilloFacial Radiology

J Brown, R Jacobs,et al
Dentomaxillofacial radiology 2014;43:20130291

Dec 19, 2014
Dr. Hyun-hee Kim

[초벌원고]

The introduction and rapid proliferation of cone beam computed tomography into dentistry means that many current practitioners did not receive training on 3-Dimensional imaging in dental school. The question for many is what is the proper level of training needed for practitioners in order to give patients full benefit of this new imaging modality while minimizing any risks. In expert group, selected from members of European academy of dental maxillofacial radiology, was tasked to develop guidelines and learning outcomes for CBCT training. Their report is available in the journal dental maxillofacial radiology. The members of this expert group were selected because they had experience in undergraduate and postgraduate CBCT education. In their report, two levels of education are suggested. Level 1 is intended for dentists who prescribes CBCT and then receive a report that interprets this imaging. The suggested knowledge for this level is an understanding of radiation safety, image quality, selection criteria, differences between 2D and 3D imaging, and local regulations. Training of this level is in vision to be a minimum of 12 hours of didactic coursework.

[수정원고]

Level 2 training includes further instruction to allow a provider to properly take CBCT scans and interpret the findings. At this level, all level 1 instruction should already be mastered. This higher level training is to include information on controlling radiation dose, geometry, and image quality to obtain a high quality scan while minimizing the patient dose. Additional level to training topics include reformating image data, preparing a structured report, instituting a quality control program, and practical use of the CBCT scanner and software. Level 2 training will likely require an additional 12 hours for the didactic work and 12 hours of practical training. Other recommendations from this group are that an image be limited only to the region of interest and that the entire image should be interpreted. The article also includes longer lists of specific learning outcomes for the different training levels which may be useful for clinicians to insure they properly understand the broader issues relating to CBCT imaging. I found it interesting how strongly this European group feels that level 1 training is necessary before even prescribing a CBCT scan. I'm not advocating for these guidelines but thought that clinicians using CBCT should be aware that they exist. If you wish to view some of the specific learning outcomes, the report is available as a short communication on the January 2014 issue of the journal Dental Maxillofacial Radiology.

Sealants Around Orthodontic Brackets Dose Not Decrease Caries

Bechtold TE, Sobiegalla A, et al.
J Orofac Orthop 2013: (October 26)

December 26, 2014
Ae hyun Park

[초벌원고]

For a long time one of the biggest problems that orthodontists faced during comprehensive orthodontic treatment has been the occurrence of white spot lesions and demineralization around orthodontic brackets. To help counteract these problems, fluoride has been introduced into sealants and bonding agents in attempt to provide a continued release of fluoride to the enamel. How affective are these sealants and bonding agents? In a study titled “In vivo effectiveness of enamel sealants around orthodontic brackets” by Till Edward Bechtold et al., which appeared in the Journal of Orofacial Orthopedics, the authors addressed this question.

[수정원고]

Their goal was to evaluate two fluoride-releasing enamel sealants in vivo to access their capability to prevent demineralization during multibracket treatment. To do this, they selected 40 patients who were about to initiate multibracket comprehensive orthodontic treatment. The patients were randomly divided into 4 groups with alternating quadrants for each patient bonded with Protecto® which is a self-curing silicone material intended for sealing a tooth surface exclusively and Light Bond® which is a light-curing system with a high filler content that has been demonstrated to provide sufficient adhesive strength for bracket bonding and is appropriate therefore for both bonding a bracket and sealing the enamel around them. These are two of the more widely used sealants in Germany where this study was performed.

The authors then used laser-fluorescence to evaluate the severity of any demineralization on the enamel surfaces around the brackets. Measurements were taken on the day of bracket bonding and after 6 months and differences between the 4 groups were statistically analyzed. The authors also accessed plaque index around each tooth. When they evaluated the differences between the 4 groups at 6 months after the initiation of the treatment, what do you think that they found? The bottom line is that neither of the two smooth surface sealants protected enamel around brackets from incipient carious lesions. Although other studies have shown the effectiveness of the enamel sealants, most of them were in vitro laboratory studies. I believe the current study has the advantage of being a randomized in vivo study which strengthen its conclusion. And although measurements were made after 6 months based on these results, there will be no reason to think that results will be different if the measured greater than 6 months.

The bottom line to me seems to be that the most effective way to minimize white spot and carious lesions is to have patients practice excellent oral hygiene. Using photographs depicting severe carious lesions of patients with poor oral hygiene and having an effective communication system to notify parents as soon as poor oral hygiene becomes evident during treatment of their children are probably still the most effective ways to support good oral hygiene. The bottom line of this study is that we are still waiting for science to deliver silver bullet to prevent carious lesions around the orthodontic brackets. You can find the study in the Journal of Orofacial Orthopedics.

Importance of Accurately Diagnosing the Presence of a Condylar Pseudocyst

Y Oded, F Slivina, et al
Am J Orthod Dentofacial Orthop 2013;144:616-618.

Jan 02, 2015
Dr. Sung Ja Kang  

[초벌원고]

A panoramic radiograph, is usually a routine part of the initial records for orthodontic treatment. In addition to providing information about the dentition including missing or malformed teeth and a sequence of eruption, panoramic radiographs provide an opportunity for orthodontists to evaluate patients who had the presence of pathology. What would you do if you were reviewing the records of a fourteen-year-old boy who came to you for orthodontic consultation because his anterior teeth were not straight? And you were reviewing panoramic radiograph, you saw a solitary, well-defined radiolucency with radiopaque borders located on the anterior aspect of the condyle. The patient presented no symptoms. Radiolucent cystic findings are not uncommon in mandibular radiographs and it is important to differentially diagnose true cyst of odontogenic or non-odontogenic origin with inflammatory or developmental pathophysiology from pseudocyst. Radiographically, pseudocysts are radiolucent and well-circumscribed and mostly appear in specific locations in the mandible. In an article titled, “Mandibular condylar pseudocyst: An introduction to the orthodontist.” by Oded Yitschaky et al which appeared in the October 2013 issue of AJO-DO. The authors present 2 case reports of patients who had condylar pseudocyst. Condylar pseudocyst appeared an anterior border of the mandibular condyle and present a solitary, well-defined radiolucency with radiopaque borders located on the anterior aspect of the condyle in asymptomatic patients. The authors suggest that this description alone is sufficient  for diagnosis of condylar pseudocyst. The diagnosis of condylar pseudcyst is important because the cysts are a radiographic variant of pterygoid fovea which is a depression on anterior part of the condyle at the site of the insertion of internal pterygoid muscle to the head of mandibular condyle. Identification of condylar pseudocyst is important because the cysts require no further radiographic image or surgical intervention. Although the authors strongly recommend a six-month panoramic follow-up to evaluate for any changes. Apparently, condylar pseudocysts have not previously been presented in the orthodontic literature and the two cases presented in this article provide an opportunity for orthodontists to become familiar with the cyst and thereby eliminate the need for further invasive treatment. You can find this article in the October 2013 issue of AJO-DO.

[수정원고]

Compliance With Removable Appliances Measured by a Sensor

Tsomos G. Ludwig B. et al
Angle Orthod 2014;84:56-61.

January 9, 2015
Dr. Ha-yeon Park

[초벌원고]

Take a moment and reflect how much of our treatment and retention success is depended on patient cooperation. If all of our patients were completely compliant, orthodontics would still be quite challenging but treatment certainly would be much easier and more predictable. Patient compliance and orthodontic treatment appears to be related to a number of factors and there are many reports and literature that have examined this complex issue. This was the area of study in the January 2014 Angle orthodontists article titled “Objective assessment of patient compliance with removable orthodontic appliances: A cross-sectional cohort study” The paper was authored by George Tsomos and his colleagues from orthodontic department in Switzerland and Germany.

[수정원고]

The objective was to evaluate patient compliance with removable orthodontic appliances and the influence of related factors. In this retrospective cohort study, 45 patients were treated at one location with retainers or active functional appliances.

The subjects' removable appliance wear time were assessed utilizing a TheraMon microsensor. The TheraMon microsensor is a 9⨉13 mm chip that can identify and record temperature changes. The microsensors were embedded in the removable appliances to record intraoral and extraoral temperatures, and thus determine appliance wear times. The prescribed wear time for the appliances were 8 hours per day for the retention group consisting of Hawleys and Essix retainers and 14 hours per day for the active functional treatment group with mainly class Ⅱ correction appliances. Age, sex and prescribed wear time were then correlated to the measured patient compliances in both groups.

The median observation period measured was 186 days and there was high individual variation in most measured variables in groups/subgroups. The mean actual wear time was 9 hours per day and the mean wear time did not differ between the two prescribed wear groups. Age was found to be a factor in compliances, as there was a significant reduction in wear time from middle childhood to early adulthood. No significant difference on compliances was found between males and females. The authors concluded that even though patients and parents were informed about wear time recording, compliance was insufficient with regard to the 14 hours per day prescribed functional treatment group. The mean wear time was sufficient for the 8 hours per day prescribed retention group. Their finding supported other studies that found compliance with removable appliances to be highly variable and multifactorial.

This article links with the findings of the Angle orthodontists November 2013 Pauls's article that reported that patients tend to overestimate their wear time by one-third. That if patients know they are recorded their more accurate and reporting wear time but knowing there is not increased their wear time, the type of appliance used and sex did not make differences in that study. The bottom line is that older adolescent patients may be more difficult to motivate than the younger ones and achieving removable appliance wear of 14 hours per day is also a greater challenge than 8 hours per day.

It would be interesting if the retention appliance group was asked to increase wear to 14 hours per day, would their mean time still be 9 hours per day? Would the Essix and Hawley retainers used in that group be easier to complied with than the functional appliances used in the active 14 hours per day group of subjects? I suspect however that these findings are supported by your clinical experiences as they are by mine. This study provides useful information for us and in particular for our staffs or often charged with providing our patients with instructions to comply in these all important treatments and retention protocols. If you would like to review this article in detail, you can find it in the January 2014 issue of the Angle Orthodontists.

Clinical Effects of Mini-Maxillary Protraction Appliance
for Class Ⅲ Malocclusions

Celikoglu M, Oktay H, et al.
Eur J Orthod 2014;36:86-92.

March 6, 2015
Dr. Ha-yeon Park

[초벌원고]

Nonsurgical treatment of Class Ⅲ Malocclusions involving early maxillary protraction using a facemask has shown to be affective in many clinical research studies. However, because the appliance is anchored on the forehead, it's poorly tolerated by some patients. To look for reasonable alternatives, researchers in Turkey examined the skeletal and dental effects of an alternative small appliance designed for maxillary protraction. The results are published in a paper called “Effects of maxillary protraction for early correction of class III malocclusion”. This paper appears in the February 2014 issue of the European Journal of Orthodontics. And I want to review the study and the findings with you.

[수정원고]

This was a case control study involving 20 patients with the class III malocclusion. All patients had an ANB less than 0°, Wits less than -1, and negative overjet. Control subjects were matched for age and gender, and since all class III patients were treated early for ethical reasons, Class Ⅰ patients were used as control subjects. All patients were treated by a single clinician using a mini-maxillary protraction appliance, a bonded expander with hooks near the canines in the maxillary arch along with the mandibular acrylic plate attached to a chin cup with the stainless-steel bow to provide a protraction anchor. This design eliminates the extension up to the forehead for support, resulting in a smaller appliance similar in appearance to a cervical headgear.

The maxillary expander was turned twice a day for 5 days, and then maxillary protraction was started for 20 hours per day. Treatment continued until 2 mm of positive overjet was obtained. In some patients, edgewise appliances were placed for anterior alignment. Lateral cephalograms taken before and after treatment were used to examine treatment effects. Overall, positive overjet was achieved in all 20 class III patients with an improvement in ANB of 3°, facial convexity of 6.3°, and Wits of 4.6 mm. This appliance moved the maxilla forward with only minor rotation of palatal and occlusal planes. In addition, the mandible rotated downwards and backwards. The overjet improved 5 mm on average with 2/3 of the change due to the skeletal correction and 1/3 due to dental correction.

The authors have demonstrated that based on the treatment effects, this may be a reasonable alternative to a protraction facemask. The smaller extraoral size of this appliances is desirable, but I would be interested to see if it stays stable and if the two layers of acrylic coverage in the mouth is well tolerated by the users. To see photographs of this appliance that may be hard to visualize from my verbal description alone, look at the full article published in the February 2014 issue of the European Journal of Orthodontics.

Long-Term Survival Rate of Teeth Receiving Multidisciplinary Endodontic, Periodontal and Prosthodontic Treatments.

Moghaddam AS, Radafshar G, et al.
J Oral Rehabil 2014;41:236-242.

March 13, 2015
Dr. Gyu-hyeng Lee

[초벌원고]

Imagine that you are considering treatment options for a 43 year-old woman named Marsha. Her malocclusion is a relatively routine Class 1 with mild to moderate crowding that you generally treat non-extraction with the exception that her upper left second premolar is in the need of endodontic treatment, crown lengthening, and the crown if it is to be maintained. You consider removing this tooth and using a mini screw to bring the posterior teeth forward but recognize that this may double the treatment time. So the question that comes to mind is: what is the expected survival rate of teeth needing complex treatment like Marsha's premolar?

[수정원고]

We have some new information from the March 2014 issue of the Jounal of Oral Rehabilitation, that provides some answers. The report is titled “Long-term survival rate of teeth receiving multidisciplinary endodontic, periodontal, and prosthodontic treatments.” This study was a retrospective study of 87 patients who underwent crown lengthening, endodotic treatment, and prosthodontic work on at least one tooth between 1996 and 2009. A total of 245 teeth were treated. Teeth with furcation involvement, considerable mobility prior crown lengthening, or a crown/root ratio less than 1 were excluded. All crown lengthening procedures were done by a single periodontist whose records were used to select the sample. Patients were recalled for clinical and radiographic exam to record bleeding point index, position of the restorative margin relative to the gingival margin, pocket depth, mobility, crown/root ratio, and reasons for any lost teeth. Teeth with severe caries requiring additional crown lengthening, extensive periodontal lesions, pocket depths greater than 7mm, or severe furcation involvement were deemed hopeless.

What the researcher's found was that a total of 18 teeth, 13 maxillary and 5 mandibular, were lost or deemed hopeless at the time of recall. The survival rate was 98% for 3 years, 96% for 5 years, 83% for 10 years, and an estimated 52% for 13 years. Survival rate in these patients was not influenced by gender, history of smoking, or the presence of a post. Teeth that have survived more than 10 years showed increased pocket depths and crown/root ratios. When examining factors to predict failure, the major determinants were found to be crown/root ratio and the position of the crown margin relative to the gingival margin.

Like all retrospective studies, this report has its limitations including some confusion about the response rate for the long-term recall. The authors also stressed that this high survival rate was the result of good interdisciplinary planning and didn't include heroic attempts to save severely compromised teeth.

So, if we think back to Marsha, the patient with the second premolar in need of significant restoration, we have information to suggest that survival rate for such a tooth is very high with good interdisciplinary care, more than 80 percent over ten years.

For more detailed information, this entire article is available in the March 2014 issue of the Journal of Oral Rehabilitation.

How Much Retraction Force Is Lost to Friction
With Various Orthodontic Brackets, Wires?

Montasser MA, El-Bialy T, et al.
Eur J Orthod 2014;36:31-38.

March 20, 2015
Dr. Ji-a Moon

[초벌원고]

Applied forces for tooth movement during orthodontic treatment are significantly affected by friction. I want to share a study with you that went to great length to investigate how different bracket and archwire combinations affect force lost to friction. This study appears in the February 2014 issue of the European Journal of Orthodonctics in a paper called "Force Loss in Archwire-guided tooth movement of Conventional and Self-Ligating brackets". Since we are consistently making decisions about which brackets and archwires to use, I thought this information maybe valuable for you as you attempt to make your treatments as efficient as possible.

[수정원고]

This was an in vitro study using the orthodontic measurement and simulation system to quantify the force measurements. This system consist of two computer-controlled measurement tables that can precisely alter their position and measure applied forces and moments through a 3D transducer. A resin replica of a maxillary dental arch was fabricated with the right canine and first premolar removed to accommodate 1 force sensor. Brackets were bonded from second premolar to second premolar with a canine bracket attached to the force sensor. Six different 0.022′ bracket systems were used: Mini-Taurus, Victory Series, Synergy, SmartClip, Time3, and SPEED. Stainless steel, NiTi, and beta-titanium 0.019×0.025′ archwires were tested in each bracket system. Traditional twin brackets were ligated with stainless steel ligatures. A 100g NiTi coil spring was attached from the second force sensor to the canine hook to provide distalizing force on the canine. The canine position was slowly adjusted for 4mm of canine retraction based on the applied force using an estimated center of resistance. The final force being applied by the NiTi coil and being felt by the tooth was recorded 20 times for each bracket and wire combination.

What do you think the researchers discovered? The Victory Series, SmartClip, Time3 brackets showed the lowest force loss and therefore were the least affected by friction. The SPEED brackets generally showed the highest force loss. Stainless steel wires showed the lowest amount of force loss, followed by NiTi archwires. Beta-titanium wires showed the highest force loss, generally 10% higher than stainless steel wires.

So the conclusion is that brackets and archwires both significantly influence the amount of force loss due to friction during canine retraction. Stainless steel wires showed the lowest force loss.

The authors also stated that there was no consistent pattern of force loss when comparing conventional and self-ligating brackets or passive and active self-ligating brackets. For more detail information regarding the performance of specific brackets tested in the study, take a look at the complete article that appears on the February 2014 issue of European Journal of Orthodontics.

Enamel Scarring by Debonding Burs
: An SEM and Profilometric Study.

Mahdavie NN, Manasse RJ, et al.  
J Clin Orthod 2014;48:14-21.

March 27, 2015
Dr. Jun-bo Jeon

[초벌원고]

One of the best experiences in orthodontic practice is taking someone’s braces off and seeing that great smile for the first time. This is also the time where we’re trying to return the enamel surface of the tooth to the same condition it was in prior to bonding brackets. There are many burs suggested to remove the adhesive, but which are objectively the best when considering surface roughness and enamel scarring? To answer this clinical question, researchers at the University of Illinois conducted a study that was published in the January 2014 issue of the JCO. The article is called, “Enamel scarring by debonding burs: an SEM and profilometric study,” and I will review some of the findings with you.

[수정원고]

In order to conduct this study in a controlled manner, the authors collected 80 extracted human premolars with no defects or restorations and mounted them in a cylindrical jig. These premolars were divided into 4 groups of 20 samples. Within each group, the surface roughness was examined on 15 samples using a profilometer. For this testing, 5 points were randomly chosen on each sample 1 to 2 mm apart for assessing roughness values. The remaining 5 samples in each group were placed in a scanning electron microscope to examine surface morphology. After the initial surface assessment, all samples were gently cleaned, etched, rinsed, and Transbond XT primer was applied. Stainless steel premolar brackets were then bonded with Transbond XT and cured for 20 seconds. Brackets were debonded one week later, and each of the four experimental groups had the remaining adhesive removed using one of the following burs: 12-fluted carbide, 20-fluted carbide, 30-fluted carbide, or white stone bur. Adhesive removal was done using a device designed to hold the handpiece and remove adhesive remnants in a reproducible manner. Following adhesive removal, the samples were analyzed again using either profilometry or SEM.

The authors found significant differences in surface roughness between finishing burs. The roughest finish was seen in the white stone group followed by the 12-fluted carbide group. The smoothest finish was seen in the 20-fluted and 30-fluted carbide groups, with no significant difference between these two. All polishing burs produced a rougher surface in the original enamel although only slightly for the 20- and 30-fluted burs. Images captured using SEM also showed the most damage with the white stone followed by scratches with the 12-fluted   carbide and smaller scratches with the finer carbides.

From this research in the standardized laboratory setting, it’s clear that final polishing with the 20-fluted or 30-fluted carbide bur produced the smoothest enamel surface with minimal scarring.

It would be interesting to also see the time required to remove composite with these various options. When I’ve used a 20-fluted or 30-fluted carbide to remove all resin, it took a long time to remove all the adhesive. It may be that using a fine bur for the final polish after removing most adhesive, could be faster. I always try to keep in mind that most general dentists will be examining these teeth at some point using magnification loops. So, I’d like to leave as smooth a surface as possible.

Find out more about the differences in surface roughness after adhesive removal in the January 2014 issue of the Journal of Clinical Orthodontics.

Dental Arch Dimensional Changes After Adenotonsillectomy in Prepubertal Children.

Caixeta ACP, Andrade I Jr, et al.
AJODO 2014;145:461-468.

April 03, 2015
Dr. Hussein Aljawad

[초벌원고]

It seems that the effects of nasal obstruction and mouth breathing have been debated forever amongst orthodontists. In the early 1970s, the work of Linder Aronson and Harvold related to the effects of nasal airway blockage on the development of the teeth and face focused attention on the possible harmful effects of mouth breathing.

[수정원고]

In article titled “Dental arch dimensional changes after adenotonsillectomy in prepubertal children” by Anna Cristina Petraccone Caixeta et al. which appeared in the April 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, has shed some further light on this relationship. In their study, the authors evaluated 49 prepubertal severely obstructed mouth breathing children and 46 nasal breathing children. The mouth breathing group was divided into 2 subgroups, one of which underwent adenotonsillectomy and the other in whom the mouth breathing pattern was unchanged during a one year study period composed the control group. The reason that the authors could develop a subgroup of mouth breathing patients that were not treated to serve as a control group was that children in this group were on a waiting list for authorization for tonsillectomy and adenoidectomy from the municipal health service in Brazil. During the time of the sample collection, it generally took more than one year for surgical approval because of high demand and low availability. Therefore, there was no ethical problem created by not treating these patients and they could be legitimately used as a match control group.

Dental casts were taken of 95 participants in this study that is 49 mouth breathing patients and 46 nasal breathing patients at baseline and again approximately 1 year later. The dental casts were used to make 9 measurements for each patient, namely; maxillary and mandibular intercanine width, maxillary and mandibular intermolar width, maxillary and mandibular dental arch length, maxillary and mandibular dental arch perimeter and maxillary palatal depth. At baseline when the mouth breathing patients were compared with the nasal breathing group, the mouth breathers had significantly higher palatal depth, mandibular intercanine width, mandibular second molar width and shorter mandibular arch length.

Basically, when mouth breathers and nasal breathers were compared, the mouth breathers had wider mandibular arches and higher palatal vaults. When the two mouth breathing subgroups were compared one year after baseline, the tonsillectomy and adenoidectomy subgroup had a significantly different pattern of arch development compared with the untreated control group. The mouth breathing children who received adenotonsillectomy showed greater maxillary intercanine and intermolar development than did the untreated mouth breathing group and the palatal vault deepened in the untreated mouth breathing children.

The bottom line of this study is adenotonsillectomies do influence arch development in adolescent children. I want to point out again that a big advantage of this study was having the mouth breathing subgroup that did not receive treatment to use as a matched control without violating any ethical principles because the reason that they were not treated was the over a year wait for approval after applying for treatment in the public health service.

You can find this article in the April 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Facial Attractiveness Not Related to Extraction, Nonextraction Orthodontic Tx.
(Original article: Maxillay arch width and buccal corridor changes with orthodontic treatment. Part 2:Attractiveness of the frontal facial smile in extraction and nonextraction outcomes.)

Meyer AH, Woods MG, Manton DJ.
Am J Orthod Dentofacial Orthop 2014;145(March):296-304

April 10, 2015
Ae hyun Park

[초벌원고]

In last month's program I reviewed part 1 of a two part article which related maxillary arch width and buccal corridor changes to premolar extraction and non extraction treatment outcomes. That study found that there were no significant differences in any buccal corridor widths or areas measured between the extraction and nonextraction subjects. They did know that there was a significant increase in the posttreatment maxillary canine width in the  extraction group but not in the nonextraction group. As I explained in last month's program, this almost has to happen because in the extraction group, canines are retracted to  a wider area of the arch which obviously results in an increase in intercanine width. In the second part of this article titled "Maxillary arch width and buccal corridor changes with orthodontic treatment. Part 2: Attractiveness of the frontal  smile in extraction and nonextraction outcomes" by Anna H. Meyer et al which appeared in the march  2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics. The authors used the same sample as part I. Part II however was designed to assess the influence that the buccal corridor might have on the frontal facial attractiveness of subjects who had received orthodontic treatment with or without four premolar extractions. In part II, full face frontal smiling photographs of the premolar in nonextraction groups were evaluated by 20 orthodontists, 20 dentists, 20 lay people who used a 100 mm visual analog scale which ranged from very unattractive to very attractive to evaluate each subject's frontal facial attractiveness. When the results of the visual analog scales were evaluated, the authors found that both orthodontists and dentists rated the frontal smiling photographs significantly higher than did the laypeople. And this difference was greater for orthodontists. There was no significant differences between the overall ratings of male and female raters, nor did number of years in practice affect the ratings of orthodontists. However the number of years in practice did have a significant affect on the ratings of  dentists with dentists with 21 to 30 years in practice giving the highest ratings. There were no significant differences between the overall ratings of extraction or nonextraction buccal corridor widths and areas  different rater groups, rater sex, or years in practice for both orthodontists and dentists. The only significant difference that the authors found was the female subjects were consistently rated as significantly more attractive than male subjects by dentists and orthodontists, but not by lay people. It would be interesting to try to understand why this difference occurred. In this article, the authors noted that most studies evaluated  buccal corridor widths used digitally altered photographs limited to the smile area. They inferred   that because they used actual full face smile photographs that their study was more valid . I'd like to point out however that the reason that most studies used intraoral photographs that were digitally altered was to eliminate extraneous variables such as hair style & color, eye attractiveness, facial contour and all the other individual variables that go into  evaluating overall facial attractiveness. I assume this is why they use black and white photographs to eliminate some these variables. They also noted that individual treatment plans tend to be biased between broader maxillary arches in short faced patients and narrow maxillary arches in longer faced patients. To me, the reason for this seems obvious. In natural faced patient are likely to have wider alveolar arches versus a narrower maxillary arch in long faced patient. The bottom line once again is that you have to keep the teeth in the alveolar arch whether you are extracting or nonextracting. And as the authors note  there are unlikely to be any significant differences in the frontal facial attractiveness of orthodontic patients either with or without premolar extraction You can find this article in the march 2014 issue of the Amercan Journal of Orthodontics and Dentofacial Orthopedics.

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Impact of Toothbrushes,
Brushing Time on Plaque, Gingival health

Zingler S, Pritsch M, et al.
Eur J Orthod 2014;36:150-163

April, 17, 2015
Dr. Ryu-Jin Moon

[초벌원고]

There's conflicting evidence whether brushing with the sonic toothbrush is advantageous for adolescent orthodontic patients and whether adding an interdental brush to a brushing routine is effective. To address this conflicting evidence,  researchers at the University of Heidelberg in Germany designed a clinical trial to provide additional information. Their study results were published in the April 2014 issue of the European Journal of orthodontics, and I'd like to share some of their findings with you. Before revealing the results, let's talk a bit about the study methods. The trial was designed to look at differences and brushing protocols during the first 3 months of orthodontic treatment. It was conducted as a prospective randomized clinical trial meeting those that agreed to participate were randomly assigned to one of the four treatment groups.

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118 orthodontic patients ages 11 to 15 completed the trial. The participants were assigned randomly to 1-4 groups. Group 1 used a sonic toothbrush and had surface sealant. Group 2 used a manual toothbrush and interdental brush and had surface sealant. Group 3 was given a manual toothbrush and surface sealant and group 4 a manual toothbrush with no surface sealant. All subjects were assessed at baseline and then every 4 weeks for the first 3 months. The assessments included several plaque indices to measure the amount and location of plaque, and the Papillary Bleeding Index to assess gingival health. The tooth brushing duration was recorded using a stopwatch for all subjects, and they were instructed to brush using their assigned technique in the morning and before bed at night. Outcomes were compared among groups 1 to 3 to determine any differences in the brushing protocols, and groups 3 and 4 were compared to measure any impact of the sealant.

Surprisingly, the authors found that the brushing time did not differ between sonic and manual brushes. It was just under 3 minutes on average. Overall plaque scores and gingival health did not differ between the sonic and manual brushes. Adding an interdental brush to the manual brush increased brushing time, but didn't make a difference on plaque or gingival health. The presence of surface sealant did not seem to impact plaque scores or gingival health. Overall the study concluded that there was no advantage in using a sonic toothbrush compared to a manual brush and no advantage could be seen when adding an interdental brush to a manual brushing protocol. The patients included in the study all had relatively good hygiene to start. The results may be different if individuals with poor hygiene habits were studied. Also, they didn't measure whether the surface sealant had any effect on decalcification, but just if it impacted plaque accumulation or gingival health. To find the full text of this article called a randomized clinical trial comparing the impact of different oral hygiene protocols and sealant applications on plaque, gingival and caries index scores, take a look in the April 2014 issue of the European Journal of orthodontics.

Improving the Hygiene Cooperation of Your Orthodontic Patients

Peng Y. Wu R. et al
AJODO 2014;145:280-286.

April 24, 2015
Dr. Jeong-sil Lee

[초벌원고]

Every orthodontist consistently wrestles with the problem of reducing  enamel demineralization and gingival inflammation which are the most prevalent consequences of biofilm formation during orthodontic treatment. Biofilm disclosing agents have long been used in oral hygiene education to promote regular brushing. Many orthodontists also use photographs which depict the severe consequences of poor oral hygiene or biofilm formation. These photographs usually demonstrate severe demineralization and gingival inflammation. If you wanted to affectively motivate your patients to achieve better oral hygiene resulting in reduced demineralization and gingival inflammation, would it be best to motivate them by using biofilm disclosing tablets or showing them photographs of the deleterious effects of poor hygiene? Would combining both of these motivational methods be more affective than using either of them individually? These questions were addressed in a study titled "Effect of visual method vs plaque disclosure in enhancing oral hygiene in adolescence and young adults: A single-blind randomized controlled trial" by Yiran Peng et al., which appeared in the march 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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In this study, the authors divided 130 participants into 4 separate groups. The subjects in one group were shown images illustrating the severe consequences of biofilm formation which included enamel demineralization and gingival inflammation. Subjects in the second group were given biofilm disclosing tablets and subjects in the third group received the combination of both methods. The subjects in group 4 served as controls. Each participant received routine oral hygiene instructions and both plaque and gingival index scores were recorded at each appointment during a 6-month follow-up. Each of the participants was bonded with traditional stainless-steel brackets.

When the plaque index and gingival index scores were statistically analyzed, what do you think the authors found? I found the results to be interesting. Both of groups that were shown only the pictures illustrating the severe consequences of biofilm formation and the group that received a combination of both methods achieved better scores than the control group on both plaque index and gingival index scores. No significant differences were found between the groups that received the biofilm disclosing tablets and the controls. When the group that received only the images illustrating the severe consequences of biofilm formation was compared with the group that received both methods of instruction, no significant differences were found, The bottom line of this study is that the most effective way to motivate patients to improve oral hygiene consisted of showing them pictures illustrating the severe consequences of biofilm formation and there was no additional benefit to using biofilm disclosing tablets.

It is nice to know that all those images of teeth that are severely decayed with accompanying gingival inflammation that are seen in so many orthodontic offices are in fact effective. You can find this article in the March 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Laser Therapy Effective in Treating Dentine Hypersensitivity

Yilmaz HG, Bayindir H.
J Oral Rehabil 2014;41:392-398.

May 8, 2015
Dr. Lijun Sun

[초벌원고]

I would like to share with you a study examining the effects of a new form of laser therapy for treating the common dental complaint of dentin hypersensitivity. The article is titled “Clinical and scanning electron microscopy evaluation of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser therapy for treating dentine hypersensitivity: short-term randomized controlled study”. It was written by Yilmaz and Bayindir from the Near East University, in Turkey in the May 2014 issue of the Journal of Oral Rehabilitation.

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The aim of this study was to evaluate and compare the desensitizing and tubule occluding effects of this type erbium, chromium laser used at different power settings. In this randomized controlled single-blinded, split-mouth clinical trial, 20 patients with a combined 60 teeth were recruited for this study to be included in the assessment. The teeth studied were required to have both moderate levels of dentin hypersensitivity and clinical indications for extraction due to periodontal disease. The degree of sensitivity was assessed by means of a calibrated blast of air on the tooth followed by the patient recording their level of pain on a visual analogue scale. For each patient, selected teeth were randomized to one of 3 groups: a placebo group or laser treatment with either 0.25W or 0.5W of power. Following one of these treatments, each tooth was reassessed for sensitivity. Then later, the teeth were extracted under local anesthesia for further analysis. The extracted teeth were prepared and then visualized with a scanning electron microscope; and the root surface characteristics and number and size of the dentin tubule openings were evaluated.

The researchers found both levels of laser treatment resulted in significantly lower sensitivity scores as compared to the placebo treatment. And also the 0.5W treatment was significantly better than the lower level of laser power. The results from the scanning electron microscopy showed that the reduction in both number and patency of the dentin tubules was also greater than the treated groups compare to the placebo. And again, the 0.5W was the most effective in tubule occlusion.

Based on these results, it was concluded that erbium, chromium: yttrium-scandium- gallium- garnet laser therapy is effective at decreasing dentin hypersensitivity and that 0.5 W provides the best results. The amount of clinical effectiveness seems to be related to the extent of dentin tubule occlusion.

This was a very well-designed study that provided clear evidence as to the effectiveness of this form of laser therapy. However, as the teeth tested were periodontally compromised enough to warrant extraction, I wonder if these results would be the same for patients with otherwise healthy dentitions suffering solely from dentin hypersensitivity. Also as noted by the authors, the need to extract the teeth for  microscope evaluation in the study prevented any possibility of performing a long-term follow-up on the stability of the desensitization. You can read this article in greater detail in the May 2014 issue of the Journal of Oral Rehabilitation.

Surgically facilitated orthodontic treatment:
A systematic review

Hoogeveen EJ, Jansma J, et al.
AJODO 2014;145:S51-64.

May 15, 2015
Jiang Tingting

[초벌원고]

In my previous review, I noted the increase in interest in utilizing techniques that facilitate orthodontic tooth movement and eventually reduce overall treatment time. While most orthodontists were not familiar with all the different approaches to facilitate tooth movement that are available, many were familiar with a different surgical treatments that have been tried as adjuncts to orthodontic treatment to facilitate tooth movement. Does surgically assisted orthodontic treatment increase the velocity of tooth movement and shorten treatment duration? Is there a difference in the incidence of tooth vitality loss, periodontal problem and root resorption between healthy orthodontic patients treated with surgically facilitated orthodontics and patients who had orthodontic treatment without surgery? Do this science of the cortical cuts and gingival flaps influence the efficiency of tooth movement and the incidence of complications? These three questions were address in an article titled “Surgically facilitated orthodontic treatment: A systematic review”. by Eelke J. Hoogeveen et al., which appeared in the April 2014 supplement and guide product issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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To address the previous questions, the authors performed a systematic literature review. PubMed, Embase, and Cochrane databases were searched for literature published until April, 2013. Randomize control trials, control clinical trials and case series with sample sizes of 5 or more patients were eligible for inclusion in review. Initially 505 studies were identified in the electronic data bases and 5 additional ones were found by hand searching the reference lists. In the end, only 18 studies met the criteria to be included in the review. As an example of problems with some of these studies the authors noted that studies in dentoalveolar distraction reported 6 to 9 months or even 50% reduction in overall treatment duration. However, no control groups were used in these studies, leaving it unclear what these calculations were based on. Based on the review of their articles, the authors made numbers of conclusions which are as follows: There was only a limited level of evidence concluding that surgically facilitated orthodontic treatment significantly reduces treatment duration compared with conventional orthodontic treatment. There was no evidence that the surgical procedures used to facilitate orthodontic tooth movement resulted in detrimental periodontal effects. No studies reported significant root shortening when compared with a control group or pretreatment root length, thereby leading the authors to conclude that limited evidence supports the conclusion that root resorption after surgically facilitated orthodontics does not exceed the resorption observed with conventional orthodontic treatment. They also noted that because of the heterogeneity of clinical indications, treatment plans, surgical techniques and force systems, it was not possible to do a meta-analysis and that most of the studies has small sample sizes. The bottom line of this study is that both corticotomy facilitated orthodontics and distraction temporarily enhance tooth movement with minimal complications. However, it is not clear how this temporary facilitation of tooth movement affects overall treatment duration.

You can find this article in the April 2014 supplement and product guide issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

What Factors Affect the Success Rate of TADs

Dalessandri D, Salgarello S, et al.
Eur J Orthod 2014;36:303-313.

May 22, 2015
Hye-young Ryu

[초벌원고]

Temporary anchorage devices, or TADs are no longer the new thing in orthodontics but rather over the past several years have become common place in modern practice. Fortunately, over this time significant research has been conducted on various aspects of their clinical use, some of which was summarized in recent systematic review by Dalesandriai et al. in an article titled "determinants for success rates of temporary anchorage devices in orthodontics: a meta analysis". The aim of the paper was to review the literature and specifically evaluate the failure rates and factors that affect the stability and success of TADs used as orthodontic anchorage.

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The authors followed the accepted standard protocol for a systematic review searching several different data bases with a logical pairing of key words. Their eligibility criteria included studies of implants or screws used as orthodontic anchorage in human. Studies could be randomized clinical  trials or prospective and retrospective clinical studies and then perhaps most significantly they only included studies that contained analysis of at least 50 TADs.

The final review of the literature applying these criteria resulted in a total 26 studies, which the authors assessed for factors that could influence the success or failure of the TADs. Encouragingly, in over all success rate of greater than 80% was reported in all of the included studies. Numerous factors were considered.  However, only those factors which had at least 5 articles pertaining to them were included in the meta analysis. In terms of patient related factors on success, this revealed that patient gender and the presence of keratinized tissue at the insertion site didn't affect TAD success. However, greater success was found for TADs placed in patients older than 20 years of age and when they were placed in maxilla compared to the mandible. The presence of inflammation also greatly negatively affected TADs success. With regards to screw design, no differences in success rates were found for implants, either shorter on longer than 8 mm in length, nor for diameters more or less than 1.3 mm. TADs success also was not affected by the time of loading either being immediately or after 4 weeks following placement.   For me the most surprising finding in this review was that TAD placement into Keratinized tissue didn't seem to increase success rates. Inflammation, however, did have a significant negative impact on success. Therefore, one might assume the reason that previous studies have found higher success and stability of TADs when  placed in keratinized oral mucosa is because the inability for inflammation to be controled adequately in non keratinized tissues. You can review this article in more detail as well as find a list of the studies included in various meta analysis in the June 2014 issue of the European Journal of Orthodontics.

Do Nickel-Titanium Closed-Coil Springs
Maintain a Constant Force Level

Cox C, Nguyen T, et al.
AJODO 2014;145:505–513.

June 12, 2015
Dr. Seung-won Lim

[초벌원고]

If you are treating an extraction case, how do you retract the canines? Probably the three most common ways are elastomeric chains, nickel-titanium coils, and closing loops. Nickel-titanium closed coil springs are more expensive than the other two alternatives, and I suspect that  most orthodontists who use nickel-titanium closed coil for retraction are willing to pay the additional cost because they believe, as advertised by the manufacturer, that these coils deliver a constant force over a longer range of activation. Is this true? A study titled “In Vivo Force Decay of Nickel-Titanium Closed Coil Springs” by Crystal Cox et al., which appeared in the April 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, addressed this question. The objective of this study was to evaluate changes in force decay properties of nickel-titanium closed coil springs after clinical use. In order to do this, the authors developed two groups for testing. The first group consisted of eleven patients for whom 30 springs were placed. This group was identified as the clinical springs group. The second group consisted of 15 springs that were placed on stainless steel plates that were stretched to 11mm of coil activation. These springs were stored stretched in a laboratory in an artificial saliva medium. In both groups, the springs were tested at 4, 8, and 12 weeks of activation. I should note that nickel-titanium closed coil springs that were used in this study were 150 gm Sentalloy Nickel-Titanium coil springs from Dentsply GAC international, which were advertised to deliver a force of 150 gm without deformation or force changed when stretched in a range of 3-15mm. All springs came from the same manufacturing lot. When the authors evaluated the force levels in the two groups at 4, 8, and 12 weeks, what do you think they found? First of all, they found that the springs on average lost approximately 12% of their initial force after 4 weeks of clinical use and there was an additional drop in force of about 7% between 4% and 8 weeks of use, after which force levels appeared to stabilize. They also found that there was essentially no difference when the spring forces were measured in vivo on the clinical patients versus in vitro in the laboratory. This findings somewhat surprise me because many research believe that in vitro research gives us much different material profile compared with clinical use. Despite the decrease in force at 4 and 8 weeks, the nickel-titanium closed coil springs achieved space closure at a rate of approximately 1 mm per month, which seems to me to be a reasonable rate of closure. It was also noted that there was significant variability in individual springs even though they all came from the same manufacturing lot. The bottom line of this study is that while the nickel-titanium springs did not deliver a constant force as advertised by the manufacturer, they were effective in closing space. Does the increased duration of activation of these springs warrant the additional cost? That’s a decision you’ll have to make based on your own experience. You can find this article in the April 2014 issue of American Journal of Orthodontics and Dentofacial Orthopedics.

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Constancy of the angle between the Frankfort horizontal plane and the sella-nasion line. A nine-year longitudinal study

Huh YJ, Huh KH, et al.
Angle Orthod 2014;84:286-291.

June 19, 2015
Zhang Fan

[초벌원고]

Sella-nasion (SN) line and Frankfort horizontal (FH) plane are two reference lines that we commonly use in orthodontics for cephalometric analysis and to evaluate longitudinal changes in our patients. When looking at the cephalometric films with our residence, I often call their attention to the angulation between Frankfort horizontal(FH) and Sella-nasion(SN). If the angle is significantly different than the typically reported 7o, we’ll look to see if the reference lines are misidentified or in an atypical position. Is the commonly reported 7o angulation between SN and FH are valid norm to consider? And dose the relationship between these widely used reference lines change with growth? In the March 2014 issue of the Angle orthodontist, an article by Young Jae Huh, and co-authors from Seoul National University in Korea, examined these questions. The article was titled ‘Constancy of the angle between the Frankfort horizontal plane and the sella-nasion line. A nine-year longitudinal study‘. The researchers stated purpose was to assess the longitudinal relationship between FH plane and SN line during facial growth.  Lateral ceohalograms were taken annually of 223 children, consisting of 116 girls and 107 boys from 6 to 14 years of age. None of these subjects received any orthodontic treatment before or during the evaluation period. A single researcher evaluated the annual cephalograms and measured the angel between FH plane and SN line in degrees, also measured with the shortest distance from FH to nasion, the shortest distance from FH to sella, and the differences between those measure distances. All measurements from serial cephalograms were compared and analyzed statistically. Now let’s go back to our first question, is the commonly reported 7o angulation between SN and FH are valid norm to consider? In this sample population, large variations were found between individuals, in the angel between FH and SN ranging from 1.8o to over 16o. The mean SN to FH angulation value shows some small change with growth with the angle tending to increase with age ranging from 9.26o to 9.74o infemales, 8.45o to 8.95o in males. How about these condquestion? Does the relationship between these widely used reference lines change with growth? That answer is yes. The mean nasion to FH, and sella to FH distance measurements increase gradually as the subjects aged. There were statistically significant differences between the sexes for all measurements of several ages. The authors concluded that within the individual, the SNFH angle remain relatively constant during growth from age 6 to 14 years, and that the measure distances from Sella, nasion to FH all increased with age. And finally, they use 7o as the typical angulation of SN to FH is questionable because of the reported wide individual variations. It would be interesting to see this study extended beyond the age of 14 as many of the male subjects would still have considerable facial growth remaining, and this study reported sexual dimorphism may have become more pronounced. The examined population was Korean, and it would be helpful if this study expended to other ethnic groups. Both FH and SN are important cepholometric reference lines that are utilized in many cepholometric analyses. This report and others confirm that both SN and FH change with growth, in cases where accuracte superimpositions are important such as the confirmation of growth completion and the evaluation of treatment affects growth changes. Employing the commonly used SN line and FH plane in growing patients for the superimposition is questionable. If you are interested in current information on cepholometrics superimpositions and excellent resource are the new videos are available on the American Board of Orthodontics website. The ABO in collaboration with educators created this excellent reference. If you’d like to review the complete paper, you can find it in the March 2014 issue of the Angle of Orthodontist.

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Evaluation of rotational control and forces generated during first-order archwire deflections: a comparison of self-ligating and conventional brackets

Pesce R, Uribe F, et al.
European Journal of Orthodontics 2014;36:245-254.

June 26, 2015
Dr. Sung-Ja Kang

[초벌원고]

Self-ligating brackets have become a popular appliance choice among some orthodontists and numerous articles have previously highlighted the practical issues that need to be considered with the their use. One such consideration is archwire selection and was the focusen article from the researchers at the orthodontic department of the University of Connecticut titled "Evaluation of rotational control and forces generated during first-order archwire deflections: a comparison of self-ligating and conventional brackets". For this study, 4 commonly available self-ligating brackets and 7 different archwire sizes and types were compared. To assess the forces from the first-order deflections for the each bracket and archwire combination, the bracket/archwire pairs were placed in a temperature-controlled testing apparatus that allowed a 5mm cantilevered segment of wire to be deflected up to 4mm. And during this time, the forces generated by the wire were recorded. Each combination was tested 10 times with a new archwire segment, and the mean activation and deactivation  forces were reported. To estimate the rotational control for each archwire/bracket combination, the first-order critical contact angle was calculated from repeated measurements of the various brackets and archwires with a digital caliper. The researchers found the predicted rotational control of each bracket was directly related to bracket depth with the ligation mechanism closed. The deeper the bracket slot, the more first-order archwire play. So, in decreasing order of control, the bracket ranking for all wire combinations was first the conventional twin bracket ligated with an elastomeric tie, followed by In-Ovation R bracket, then SmartClip, Carriere, and then Damon 3MX bracket. As for the forces generated during first-order deflections, the general trends were increasing forces with increased wire sizes, and that multi-stranded wires generated lower forces than their single-stranded counterparts of the same size. The results of this study provide us these following conclusions. One, self-ligating brackets have considerable first-order slop compare to conventionally ligated brackets and two, because of this, utilizing a rectangular multi-stranded NiTi archwire that fills the slot depth, such as those described in this study, will allow you keep the forces relatively low yet delivered some elements of rotational control for full alignment. You can find all the details regarding  the specific properties of the archwires and brackets used in this study , in a full version of this article by Pesce et al. in the June 2014 issue of the European journal of Orthodontics.     

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The Influence of Prebrushing Mouthwashes on Plaque Removal in Children

Miranda RDS, Marques RA, et al.
Pediatric Dentistry 2014;36:211-5.

July 3, 2015
Dr. Sei-won Jun

[초벌원고]

Maintaining adequate oral hygiene is a constant challenge for many of our orthodontic patients. A relatively new line of products with aim of improving both the effectiveness and motivation in tooth brushing are pre-brushing mouthwashes. These mouthwashes contain both the chemical anti-plaque agent as well as a disclosing dye that purports to highlight dental plaque. I would like to share with you the results of an excellent study examining the clinical effectiveness of two of these mouthwashes in an article titled: "The Influence of Pre-brushing Mouthwashes on Plaque Removal in Children" from researchers at the school of dentistry of the Federal University at Santa Maria in Brazil.

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The study design was a randomized, double-blind crossover clinical trial. Researchers recruited 38 subjects with at least 24 permanent, erupted teeth from a local primary school. Children with either severe malocclusions and overjet greater than 3 mm, or psycho-motor limitations were excluded from participation. For this trial, two commercially available mouthwashes, Listerine Agent Cool Blue and Golgate Plax Magic, were compared to each other and to two control solutions; distilled water and a dye, and with distilled water alone. At the start of the trial, a baseline plaque index was determined for each subject, were then instructed to rinse for 30 seconds with a randomly assigned mouthwash, and then brush his or her teeth without tooth paste. After tooth brushing, the plaque index was evaluated again to determine the mouthwash effectiveness by way of reduction in plaque index score. The subjects were then left for seven-day washout period during which there were to refrain from brushing for at least the last three days. The subjects were then recalled, and the testing was performed with the second randomized solution, and so on until all four solutions have been used by each of the participants. So what with the results of this study? Well, not surprisingly, the initial plaque index was not higher than the final plaque index for each mouthwash tested. That is to say, that when the patients brush their teeth, they were at least somewhat affected by getting them clean. However, this effect was observed for each of the mouthwashes used with no differences in amount of plaque reduction found among the different products.

The commercially available mouthwashes were no more effective in reducing plaque index than water when used as pre-brushing rinse. So, it seems based on the results in this clinical trial, that pre-brushing mouthwashes are no effective in plaque removal in children. As it was outside the aim of the study, the long-term effectiveness of similar rinses was not assessed. However, for the purposes of  highlighting presence of dental plaque, in my opinion, nothing beats the classic vegetable-dye based red disclosing tablet that many of you are no doubt familiar with.

 You can find the full version of the study by Miranda and colleagues in the May-June 2014 issue of the Journal Pediatric Dentistry.

Randomized controlled trial
Assessment of changes following en-masse retraction with mini-implants
anchorage compared to two-step retraction with conventional anchorage in
patients with class II division 1 malocclusion: a randomized controlled trial

Al-Sibaie S, Hajeer MY. et al
European Journal of Orthodontics 2014;36:275-283.

July 10, 2015
Dr. Hyun-Hee Kim

[초벌원고]

In the camouflage treatment of Class 2 div 1 patients in your orthodontic practice, do you routinely use a TPA to supplement your anchorage? Or perhaps you prefer to employ a two-step retraction protocol where you first retract maxillary canines followed by the incisors. If so, you may find the results of following article enlightening. The article is titled “Assessment of changes following En-masse retraction with mini-implants anchorage compared to two-step retraction with conventional anchorage in patients with Class II division 1 malocclusion: a randomized clinical trial“ and it was written by Al-Sibaie and Hajeer from the University of Al-Baath in Syria. In this single blinded perspective randomized clinical trial, 56 adult patients diagnosed with full cusp class II malocclusion planned for upper first premolar extraction were studied.

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Patients were allocated in equal numbers to either the two-step retraction: TPA group or the En-masse retraction mini-implants group. The TPA group had a TPA soldered to the maxillary first molar bands and Once 0.019′ × 0.025′ stainless steel archwires was placed, the Maxillary canines then incisors were retracted with sliding mechanics. The mini implant group had screws placed between the maxillary second premolars and the first molar with the anterior teeth retracted directly from the mini implants to a soldered hook on a 0.019′ × 0.025′ stainless steel archwire. Lateral cephalographs were taken pre-treatment and also before and after the closure of the extraction space. So what was the result of this clinical trial? Well, the retraction of the maxillary incisors took an average of 4 months less in the mini-implant group, where the incisors were bodily retracted and intruded, and the first molars distalized slightly. The incisors in the 2-step TPA group distalized through controlled tipping and the first molars mesialized 1.5 mm, indicating a loss of anchorage. Both groups show significant retraction of the upper and lower lips with treatment.  Based on these result, it was concluded that compared to 2-step retraction reinforced with TPA anchorage, the en-masse retraction of anterior teeth utilizing mini-implants resulted in shorter treatment time and true posterior bodily movement of the incisors and maxillary first molars. Clearly, this was a well planned and executed study. However, it would have been interesting to see a comparison of patients’ preference between the two treatment mortalities. And the authors has could have been strengthened the impact of their work by making an objective comparison of the final occlusion between the two groups. Nonetheless, this is yet another study showing the superiority of skeletal anchorage compared to the traditional forms of the anchorage support.

The result of which should be considered the next time you plan camouflage treatment of Class II division 1 malocclusion. The full details of this clinical trial can be found in June 2014 of European journals of Orthodontics.

Effect of Premolar Extraction and Presence of the Lower Third Molar on Lower Second Molar Angulation in Orthodontic Treatment 

You TM, Ban BH, et al.
Oral Surg Oral Med Oral Pathol Oral Radiol 2014;118:278-283.

September 4, 2015
Dr. Ha-yeon Park

[초벌원고]

At this point in time, the literature is quite clear in the non-significant role of that third molar’s play in post-orthodontic relapse. However, less is known about the reverse relationship. How does orthodontic treatment affect the likelihood of an impaction for erupting third molars? This was just a question examined by researchers from Dankook and Yonsei Universities in South Korea in the article titled “Effect of Premolar Extraction and Presence of the Lower Third Molar on Lower Second Molar Angulation in Orthodontic Treatment”. For this retrospective study, patients presenting to a university dental hospital for extraction of the their third molars over a twelve-month period were screened for eligibility. The patients meeting the screening criteria of unerupted third molars were placed accordingly into either of the control group of 65 patients who had no orthodontic treatment, the extraction group of 30 patients who had orthodontic treatment with premolar extractions, or the non-extraction group of 34 orthodontically treated patients. Anatomical landmarks were used to create horizontal and vertical reference planes on the patients’ panoramic radiographs. Then, the long axes of the first and second molars were traced and the differences in angulation, as well as the relative angle ratio between the 2 teeth, were calculated. The authors noted that ratios were used to minimize potential errors caused by magnification and distortion of the panoramic radiographs. Following the analysis, the authors found that the angulation of the second molars was slightly mesial or parallel to the long axis of the first molar in the control, unextraction groups. However, in the patients treated orthodontically without extractions, the second molar angulation tended to be more often tipped distally. This led the authors to conclude that this may be an indication for preorthodontic extraction of third molars in adolescent orthodontic patients treated without extractions. And they state that this is because the distoangulation of the second molars has the potential to increase the impaction of the third molars and to render subsequent extraction more difficult. However, there are several issues with the study that limit the strength and generalization of its conclusions. First, the ages of the patients in each group were not reported, nor were the vertical or AP skeletal relationships of the patient population. As each of these factors could easily affect the space between the terminal molar and the ramus, as well as the direction of tooth movement during treatment, I feel that they specifically should have been included in the analysis. You can find the full version of this article by You and colleagues in September 2014 issue of Oral Surgery, Oral Medicine, Oral Pathology, and Oral Radiology.  

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A Cost-Minimization Analysis of an RCT of Three Retention Methods

Tynelius GE, Lilja-Karlander E, et al.
Eur J Orthod 2014;36:436-441.

September 11, 2015
Dr. Gyu-hyeong Lee

[초벌원고]

I’m often surprised to hear the amount of variability in retention protocols used by different orthodontists both in terms of duration and choice of appliance. When developing a rational for the retention protocols that you use with your patients how often you include cost as part of the consideration. Let me share with you the findings from a recent study titled “A cost minimization analysis of an RCT of three retention methods” by researchers from the university of Malmö in Sweden to help you make an informed decision for your practice. The aim of this paper was to reanalyze the data from previously published randomized controlled trail of the effectiveness of 3 methods of retention now to focus on the financial aspects of providing treatment via a cost minimization study. Its important to know that this early study found that 3 protocals described all were equally effective after a period of 2 years. The study sample consisted of 75 class I crowded patients 45 of which were females all less than 20 years of age with normal transverse and vertical skeletal relationships. All patients were treated orthodontically with the extraction of 4 premolars. Following treatment patients were randomly assigned to 1 of 3 retention protocols the first consisted of a maxillary vaccum formed retainer in combination of a mandibular lingual retainer bonded to the canines. The second protocol also had a vacuum formed retainer for the upper arch with only interproximal stripping of the mandibular incisors. And a third group was given prefabricated positioner. Patients were told to wear the retainer for 2 days of full time wear and the nightly for the first year followed by wear every other night for second post treatment year. Using an extremely detailed schedule of expenses for each protocol which included everything from the alginate for the imprssions to the time missed from school or work or appointments or the direct and indirect cost were calculated. Using data from the patients records the cost associated with unscheduled visit were all also determined so what were the results.

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Well the researchers found that the vacuum formed lingual bonded retention protocol group had the highest combined direct and indirect costs while the costs for the positioner group were the least. The vacuum formed lingual bonded group also had the greatest number of unscheduled visits and associate costs which made it significantly less cost effective compared to the other groups. It would be interesting to see the study repeated in north America as for my view point some of the costs assigned with specific clinical procedures and materials would be significantly different. However the study does highlight the greater number of unscheduled visits and clinical time required for bonded lingual retainer compared to removable forms or retention.

You can find the complete article by Tynelius et al. including the details of the costs specific to each group retention protocol were used in the august 2014 issue of the European Journal of Orthodontics.

A preliminary study of the effects of low-intensity pulsed ultrasound exposure on the stability of orthodontic miniscrews in growing rats.

Miura K, Motoyoshi M, et al.
Eur J Orthod 2014;36:419-424.

September 18, 2015
Dr. Ji-a Moon

[초벌원고]

While research on the use of miniscrews for anchorage in the orthodontic treatment of adults are showing very good success rates. Miniscrews in younger growing patients have been more problematic. Setting the frequent loosening of miniscrews in growing patients researchers from Nihon University in Tokyo search test the applicability of the low intensity pulsed ultrasound also known as like this as a technique for increasing implant stability. This work is published in the August 2014 issue of the European Journal of orthodontics in the article titled "A preliminary study of the effects of low intensity post ultrasound exposure and the stability of orthodontic miniscrews in growing rats". For this study custom-made titanium self-tapping miniscrews which were 1.4mm in diameter and 4.0mm in length, were surgically placed into both the right and left tibia of seventh Sprague-Dawley rats that were six weeks in age. The authors note that rats of this age are undergoing rapid growth and in their words a six week old rat would be equivalent to the growth period of 10 to 12-year-old human child. Following surgery low intensity pulsed ultrasound and frequency of 3 MHz was used to stimulate the right tibia of each rat for 15 minutes per day beginning immediately after placement. The left tibia well Kept untreated and used as controls. After a 2-week period the rats were sacrificed and the tibiae dissected and cleaned and then mounted in plaster with the miniscrew head exposed. The mobility of each miniscrew was then measured perpendicular to its long axis using a mobility testing device to assess bone contact with the implants the specimens were then  prepare for imaging with field-emission scanning electron microscope with sections made through the center of the screw along its long axis. Using paired t-test to compare the treatment and control specimens of each animal the results from the study were clear. The miniscrews in the test group has significantly less mobility than the controls and significantly greater amounts of bone to miniscrew contact. The authors conclude that low-intensity pulsed ultrasound can improve the stability of miniscrews in growing subjects. I thought that this was a very well-connected study which clearly demonstrates that low-intensity pulsed ultrasound, as a technique, shows great promise for increasing success rates of TADs. Future research will have to verify if these impressive early results can be duplicated in humans. Again you can find this study by Miura and colleagues in the August 2014 issue of the European Journal of orthodontics.

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Scoring of Ceramic Bracket Bases for Easier Debonding.

Silveira GS, Bittencourt LP, et al.
J Clin Orthod 2014;48:441-442.

September 25, 2015
Dr. Seung-weon Lim

[초벌원고]

Ceramic brackets have become a staple in the armamentarium of orhtodontists, for patients concerned with ethetics while undergoing orthodontic treatment with fixed appliances. However due to a high bond strength to enamel and decreased fracture resistance compared to stainless steel, debonding ceramic brackets can it times be problematic. The risk of damage to the enamel surface exists though a more common occurrence is the random fracture of the bracket while debonding it resulting in fragments of ceramic remaining on the tooth.

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I'd like to share with a clinical tip presented in a recent issue of the journal of clinical orthodontics which I believe effectively addresses many of the complications associated with debonding ceramic brackets. So here is the procedure, following removal of the archwire, a long tapered diamond burs used to score the center of the bracket between the tie wings creating a line perpendicular to the bracket slot. the idea here is to create a stress concentrating line along which the bracket will fracture when compressed. Once the line is scored into the bracket base use a Weingart or a How plier with the tips placed on the mesial and the distal sides of the bracket and squeeze the tie wings together. This will cause the bracket to fracture the midline and debond. If one half of the bracket happen to stay on the tooth, it can be removed easily by rocking it gently back and forth with the same plier. Complete the procedure by removing any remaining adhesive using a low speed 12 blade tungsten carbide bur with a smooth rounded tip under dry field. Then polish the teeth as you normally would which in my practice involve using a  rubber cup at low speed and a fluoride containing prophylaxis paste. This simple clinical tip seems like an ideal method to debond ceramic bracket while dramatically decreasing the risk of damaging the enamel surface. This would be particularly useful in patients with sensitivity or with restorative work on facial surface of the tooth.

Pictures illustrating the technique presented can be found in the article titled "Scoring of Ceramic Bracket Bases for Easier Debonding" in the July 2014 issue of the JCO.

Is Maxillary Dental Arch Constriction Common in Japanese Male Adult Patients With Obstructive Sleep Apnoea?

Maeda K, Tsuiki S, et al.
Eur J Orthod 2014;36:403-408.

October 2, 2015
Dr. Hussein Aljawad

[초벌원고]

For sometime now it is well recognized that a reduced oral pharyngeal space either due to an enlarged tongue or retrognathic position of the mandible is a risk factor for obstructive sleep apnea in adults. However the influence of transverse constriction of the dental arches on obstructive sleep apnea in adults is not nearly as well understood. It was this notion that led researchers from Tokyo to question and study titled “Is maxillary dental arch constriction common in Japanese male adult patients with obstructive sleep apnea” which appeared in the August 2014 issue of the European Journal of Orthodontics.

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To answer this question the authors recruited the adult male patients with intact dentitions who were referred to their sleep apnoea clinic for treatment with a mandibular advancement splint. This resulted in a total sample of 164 with an average age of 45 and moderate severity of obstructive sleep apnea. The initial lateral cephalographes and dental study models were analyzed and relationships between the various dental cephalometric and OSA parameters were determined. Following an appropriate statistical work up the authors reported that overall only 6% of the patients had a posterior crossbite and the maxillary dental and alveolar width were not significantly different from previously published normative Japanese values. Maxillary dental arch width was found to be positively correlated with BMI and negatively correlated with AHI (Apnea-Hypopnea Index). However maxillary transverse characteristics were more strongly correlated to measures of retrognathia. These results led the authors to conclude that maxillary dental arch constriction is weakly associated with OSA severity, the more often related to an anteroposterior discrepancy between the dental arches as opposed to a true skeletal maxillary constriction.

This was a simple yet effective study to demonstrate that a narrower upper dental arch is not a common feature of adult OSA patients at least in the Japanese population evaluated. Interestingly, when present, maxillary dental constriction was more often found as a compensation for retruded lower arch, a finding that previously has been shown as more strongly related to OSA symptoms. Also as the dental arches don’t narrow significantly with age the authors used these results to imply that maxillary constriction’s would therefore not be a significant contributor to OSA in a pediatric population. However they also know that perspective studies are needed to form this rough assumption. You can find the complete details of this study as well a full version of the article by Maeda and colleagues in the august 2014 issue of the European Journal of Orthodontics.

A comparisin of tapered and cylindrical miniscrew stability

Yoo SH, Park YC, et al.
Eur J Orthod 2014;36:557-562.

October 23, 2015
Dr. Youn-Gyeong Moon

[초벌원고]

When choosing which type of miniscrew to use for skeletal anchorage in your practice how much do you consider screw design in your deciscion. I'd like to share with you the findings of reason article that I think will helps you with this question. The article is titled "A comparison of tapered and cylindrical miniscrew stability" it comes from faculty of Department of Orthodontics of Yonsei University in Seoul Korea. For this prospective clinical trial designed to compare both short and long term miniscrew stability all patients older than 16 years of age requiring skeletal anchorage as part of their orthodontic treatment over 3 year period were recruited for participation. For this study all miniscrews were 1.5mm in diameter and 7.0mm in length and had the same color and head design with the only need external shape of screw different between the samples. When clinically indicated miniscrews were bilaterally placed into the buccal alveolar bone of either the maxilla or mandible, as dictated by the orthodontic treatment plan of the patient. most patients received both a tapered and cylindrical miniscrew, with the right or left position of each type randomly assigned. A consistent insertion technique without a pilot hole was used and all miniscrews were medially lower with 200~250g force. As an assesment of initial miniscrew stability the insertion torque, and Periotest values were measured at the time of placement, while removal torque and Periotest values were used to assess long term stability at that time of screw removal. Correlations to overall success rate and specific patient characteristics were also evaluated. As a result of the study a total 105 tapered and 122 cylindrical miniscrews placed in a total of 132 patients were evaluated. The average placement period was 15 months for both design and the overall success rate of both designs ended up mean similar, however, the tapered miniscrews showed greater initial stability compared to the cylindrical miniscrews when placed in the maxilla only. Measures of long term stability were not significantly different between screw designs for either jaw. These findings at the authors conclude that the long term stability and success rate is not directly affected by miniscrew design. I thought this was a well perfomed clinical trial that effectly demonstrated that in the long term, little clinical differences exist between tapered and cylindrical design of miniscrews. Furthermore, the authors reported that there were no differences in success rates based on gender, jaw, or side of insertion. However miniscrews placed between the first and second molars did show a significantly lower success rate compared to all other sites of insertion. So the next time you are considering the merits of particular miniscrew to use in your practice keep in mind the result of this study. The full version of the article can be found in the October 2014 issue of the European Journal of Orthodontics.

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Mandibular kinematic changes after unilateral cross-bite with lateral shift correction

Venancio F, Alarco N, et al.
Journal of Oral Rehabilitation 2014;41;723-729.

November 06, 2015
Dr. Hyun Hee Kim

[초벌원고]

For the treatment of unilateral posterior cross-bite, several options both in terms of appliance and technique have been advocated. Though limits of research exist on the functional outcomes of cross-bite correction, they might guide our decision process. In an article titled Mandibular kinematic changes after unilateral cross-bite with lateral shift correction, spanish researchers from the university of Granadasetto evaluate the effects of slow expansion with either there movable expansion plate or bonded Hyrax expander.

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For this prospective randomized clinical controlled trial, thirty children between the ages of seven and twelve were recruited from patients referred to the university pediatric dental clinic for treatment of a cross-bite and lateral mandibular functional shift of at least and a half millimeters.  Thirty age-matched children with normal occlusion from the same clinic served as the control group. The patients were then randomly assigned to either the expansion plate or Hyrax expander groups.

Both appliances were designed with occlusal acrylic coverage, and the expansion plate group was instructed to use the appliance at all times except for meals and brushing. Patients in both groups were instructed to turn the expansion screw of their appliance twice a week and expanded until 3mm of overcorrection was observed. In terms of mandibular kinematics, it was the magnitude of the maximum vertical opening, mandibular lateral shifts as well as lateral excursions of subjects which were evaluated both before and 4-month after active expansion.

The results from this trial found that the average time were required for treatment was 12 months for the expansion plate group, compared to 3 months in the Hyrax expander group. Significant differences in mandibular functional movements were found between the control and both cross-bite groups initially. Following treatment, these differences were largely eliminated. However compared to the expansion plate group, patients treated with the Hyrax expander appliance had significantly improved mandibular lateral shifts in a normalized range of lateral excursions.

On the basis of these results, it was concluded that well both treatment modalities produced favorable changes in the kinematics of the mandible. The Hyrax expander group had a greater amount of improvement which was also achieved in significantly less time.

I rarely use the removable expansion plate in my practice, mainly because of the tremendous amount of patient complaints required to make this form of cross-bite corrections successful.  From the results of this clinical trial, it would seem that a bonded Hyrax appliance is preferred not only in terms of the practical considerations of compliance and treatment time, but also in this superior functional outcomes achieved through treatment.

You can find the complete version of this article by Venancio et al in the October 2014 issue of the journal of oral rehabilitation.

The Dental Connection to Bullying
(Esthetic Dental Anomalies as Motive for Bullying in Schoolchildren)

Scheffel DL, Jeremias F, et al.
Eur J Dent 2014;8:124-128.

November 13, 2015
Ae-hyun Park

[초벌원고]

I remember an orthodontist I trained with who shall remain nameless once talking to me about FLKs. For the longest time I had no idea what he was talking about- couldn't find it any textbooks - I was beside myself.

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When I asked him, he replied out of the corner of his mouth "FLK, funny looking kid." I've since thought to myself that it we as dentists identify FLKs, which I believe we all do, what must these kids go through at school? With this in mind, I have elected to review "Esthetic Dental Anomalies as Motive for Bullying in Schoolchildren by Debora Scheffel et al, Universidale Estadual in Brazil and published in the 2014 issue of the European journal of Dentistry.

A smile can denote self-esteem, self-confidence, and overall positive body image. Historically, children with concerns about their teeth may demonstrate reduced smile security. This case series presented cases in which children were bullied due to visible tooth anomalies. The authors outlined a case of a 10-year old with amelogenesis imperfecta who sought care with a chief complaint of extractions and seeking dentures at the age of 10 that teasing at school contributed to poor test performances and overall social withdrawal by the young girl. Another case described as an 8-year old with molar-incisor hypomineralization in which the teeth were the source of the child being mocked for having "rotten teeth" and rumors that the child did not brush their teeth went around the school as well.

The Questioning on hygiene habits also began to rise from within the family. It is important to note the most common forms of bullying are verbal estimated 31% of all cases, followed by rumors spreading(25%) and finally physical aggression(14%). This article was "Esthetic Dental Anomalies as Motive for Bullying in Schoolchildren by Debora Scheffel et al, Universidale Estadual in Brazil published in the 2014 issue of the European journal of Dentistry.

I was drawn to this paper it represents real insight into the whole chid concept. We may see dental anomalies, but  the child sees a source of shame and sometimes fear. In some cases when we treat these children, we may need to counsel our pediatrician, mental health colleagues. I don't see FLKs anymore- just children who may be more fragile and many need help beyond just our resins and crowns.

Influence of Dental Esthetics on Finding a Job

Pithon MM, Nascimento CC, et al.
AJODO 2014;146:423-429.

November 20, 2015
Jung Sil  Lee

[초벌원고]

When Patients come to your office for treatment and ask you about the benefits  of orthodontic treatment, what can you tell them? Can you tell them that they will have an increased likelihood of being hired for a job? Can you tell them that they will be perceived as being more honest? Can you tell them that they will be perceived as being more intelligent? Lastly, Can you tell them that they will be perceived as being more efficient as a worker? What do you think? All of the above? None of the above? Or some of the above?

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A study titled, 'Do dental esthetics have any influence on finding a job?' by Matheus Melo Pithon et al. which appeared in the October 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics, addressed these questions. In this study, the authors identified 10 patients who presented with malocclusions. They then digitally altered the patient's teeth to achieve ideal alignment. Next, they divided the photographs into 2 groups, each of which contained some patients with the original smile photo and others with the digitally improved ideal smile. Neither of the two groups contained the same patient twice. They then had the images in the two groups evaluated by 100 persons responsible for hiring staff for commercial companies. Evaluators used a visual analog scale from 1 to 100 millimeters related to 4 questions. Would you hire this person? Does this person appear to be honest? Does this person appear to be intelligent? Does this person appear to accomplish his or her task on time? So what do you think the result showed?

The bottom line is that persons with ideal smiles are considered more intelligent and have a greater chance of finding a job when compared with persons with none ideal smiles. There was no relationship between smile esthetics and honesty and accomplishing tasks on time. So, you can now tell your patients who ask you about the benefits of orthodontic treatment that research has shown that they will be viewed as more intelligent and have a greater likelihood of getting a job. The use of Digital morphing now allows researchers to isolate a single variable for evaluation. In this case, they were able to vary the alignment of teeth while keeping other facial features exactly the same. You can find this article in the October 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics

The influence of amalgam fillings on the detection of approximal caries by cone beam CT: in vitro study

Kulczyk T, Konwinska MD, et al.
Dentomaxillofac Radiol 2014;43:20130342

November 27, 2015
Zhang Fan

[초벌원고]

We all well aware of the expanse use of CBCT imaging in dentistry, and certainly know of the benefit of this technology for specific indications in Orthodontics. However, our recent study in the Journal of Dentomaxillofacial Radiology explored a novel use of CBCT imaging and that is for the assessment of dental caries. The article is titled “the influence of amalgam fillings on the detection of approximal caries by cone beam CT: in vitro study” and it was published by researchers from Poznan University of Medical Sciences in Poland. As the title suggests, their goal was to analysis the ability of CBCT to detect non-cavitated carious lesions located on the interproximal mesial and distal surfaces of teeth located next to a tooth with amalgam filling.

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The experimental set up consists of obtaining 102 non-cavitated, non-restored human premolar and molar teeth. The teeth were placed in silicone and arranged contacting each other in set of 4 mimicking a quadrant of 2 premolars and a first and second molar. The first molar in the set was then restored with a mesial-occlusal-distal amalgam filling. In total, 34 of these quadrant sets of teeth were prepared for CBCT imaging. For this, each set was immersed in a container of water and scanned with a NewTomTM 3G CBCT machine using a 9-inch field of view and 0.25-mm voxel size. The generated images were then examined in 0.25-mm sections in the mesiodistal plane by 2 experienced dental radiologists using the NewTomTM imaging software. The presence of caries was then evaluated on a 5-point confidence scale, ranging from definitely caries present to definitely no caries present. All examinations were performed independently twice with a 2-week interval in between following the CBCT examination. All teeth adjacent to the restored first molar in the quadrant samples were then individually mounted in acrylic resin and sectioned in the mesiodistal plane and visualized under a light microscope to establish the true histological status of caries at each surface. With these histological sections taken as a gold standard, the accuracy and reliability of the CBCT assessment of caries at each mesial and distal surfaces of the tested teeth were determined.

For the results, the authors reported that the sensitivity of CBCT for detection of interproximal caries ranging from 0.27 for enamel to 0.56 for dentin. Specificity values were equally low ranging from 0.53 for enamel caries to 0.38 for caries extending into dentin. These findings let the author to conclude that CBCT scan should not be used for the assessment caries when metal restorations are present in teeth adjacent to the site of interests.

So there you have it. Despite many uses, current CBCT technology is not suitable for the detection of non-cavitated carious lesions, especially when located near metal restorations. As this was an in vitro study that allow ideal imaging conditions. I would expect that in vivo detection of caries with CBCT which would be subjected to patient movement would fare even more poorly.

To read the fully detail of the study, look for the complete version of this article by Konwinska et al. in a 2014 issue of Dentomaxillofacial Radiology.

Adenotonsillectomy and Orthodontic Therapy in Pediatric Obstructive Sleep Apnea 

Villa MP, Castaldo R, et al.  
Sleep Breath 2014;18:533-539. 

December 4, 2015
Dr. Jun-Bo Jeon

[초벌원고]

Many of you are aware of the significant role that we as orthodontist can play in the care of both children and adults with obstructive sleep apnea. Recently Dr. Maria Pia Vila, one of the pioneers of applying rapid maxillary expansion as a treatment for children with obstructive sleep apnea, published new data that I think you should become familiar with. The article is titled “Adenotonsillectomy and orthodontic therapy and pediatric obstructive sleep apnea” and appears in the September 2014 issue of the journal sleep and breathing.

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The aim of this prospective cohort study was to evaluate the outcomes of Adenotonsillectomy and rapid maxillary expansion treatment in a selected group of children with obstructive sleep apnea. Participants of the study included consenting children who presented to the pediatric sleep center of Sapien's University in Rome with a complaint to sleep-disordered breathing.

The protocol consisted of all children undergoing an examination by an orthodontist and otolaryngologist in addition to a full overnight sleep study. Based on the polysomnography results in clinical finding, the patients were then divided into two treatment groups. Group 1 which underwent adenotonsillectomy consisted of all of children with an AHI or apnea-hypopnea index of greater than 5, regardless of the presence of malocclusion. Group 2, which underwent rapid maxillary expansion, consisted of children who were older than 4 years of age with an AHI less than 5. This group of children also had a malocclusion which in the opinion of the attending orthodontist more to do expansion, regardless of the presence of hypertrophic tonsils and adenoids.

The technique for the rapid maxillary expansion consisted of 5 millimeters of expansion followed by holding period of 12 months with the appliance left in place. At one year follow-up, patients from both groups underwent a second overnight sleep study and the changes from baseline were compared.

Now considering the results of the treatment, it's important to know that patients were not randomized to either group but rather specifically chosen for one treatment or another based on their clinical characteristics. So surgical treatment group consisted of 25 children who were younger with an average age of 3.7 years and more severe obstructive sleep apnea, with an initial AHI 17.3 following Adenotonsillectomy, these children saw significant improvement in OSA symptoms and decrease in their AHI to 1.8. The 22 children in group 2 or older with a milder form of obstructive sleep apnea with average initial age and AHI of 6.6 and 5.8 respectively. At the 12 month follow-up following RME, this group showed improved symptoms and AHI decrease to 2.6.

These results led the authors to conclude that both adenotonsillectomy and rapid maxillary expansion can improve obstructive sleep apnea in children with skeletal malocclusion. This is important to study adds to the emerging evidence highlighting the utility of rapid maxillary expansion as a treatment for some obstructive sleep apnea children. However, unfortunately the children were not randomly allocated to the treatment groups so ultimately this is just observational data. And additional criticism is that it is not clear by which criteria they treating orthodontist chose to apply treatment, as not every child who had RME, has an actual posterior crossbite.

Perhaps it was this subjective application of treatment by the results in and outcomes less effective in those reported in previous studies. It is also important to point out that four of the children who underwent expansion actually had their OSA symptoms become significantly worse.

Clearly more research is needed to determine in which OSA patient's rapid maxillary expansion treatment would be most appropriate. The full version of this article by Pia Vila et al can be found in the September 2014 issue of sleep and breathing.

Stability and Relapse After Orthodontic Treatment of Deep Bite Cases—A Long-Term Follow-Up Study

Danz JC, Greuter C. et al.  
European Journal of Orthodontics 2014; 36:522-530 

December 11, 2015
Dr. Sun Lijun

[초벌원고]

Excess overbite or deep bite is a relatively common finding in untreated malocclusions. In these cases, treatments are often recommended in order to reduce or prevent tissue trauma from tooth contact, and reducing increased tooth wear. The orthodontic correction of the severe deep bite cases can be quite challenging. And so it was natural to want to maximize stability in such instances.

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In the recent issue of the European Journal of Orthodontics, the question of deep bite stability was examined by Danz and colleagues. In the article titled “Stability and relapse after orthodontic treatment of deep bite cases—a long-term follow-up study”. The aim of the article was to assess the problems of relapse after the treatment of deep bite malocclusion and to attempt to identify risk factors that predispose patients to relapse.

For this retrospective study, attempts were made to recall all patients treated from 2000 to 2002 in the orthodontic clinic of the University of Bern in Switzerland who also had an initial overbite of greater than 50%. Due to loss of patient contact or ineligibility criteria, 43 patients who had their deep bite successfully corrected during the treatment were included in the final analysis. Data collection included measurement of initial, post-treatment, and recall records consisting of dental casts and lateral cephalographs. At the recall appointment, patients were classified into a relapse or stable group based on whether or not they had an overbite greater than 50%. The patients were initially treated with a variety of treatment modalities and an average initial age was 12 years. However, most were retained with mandibular bonded lingual retainer and a maxillary removable Hawley appliance.

So what were the key findings? Well, average treatment time of the study sample was just over 3 years, and the recall period was significant at almost 12 years in length. At recall, 77% of patients still had a fixed mandibular retainer in place. Only 4 of the 43 patients or 10% of the sample had relapse of overbite to greater than 50%. Due to the small number of relapse patients, logistic-regression analysis on predictive characteristics of relapse was not feasible. Base on these result, the authors concluded that the prevalence of vertical relapse in moderate deep bite cases after a median post-treatment follow-up of 11.9 years was low 10%.

I was interested by the initial question posed by the study. But unfortunately, due to the extended follow-up period, the authors were only able to recall a small sample of patients, which made any discriminatory analysis impossible. However, it appears that successfully treated deep bite cases have excellent long-term stability, though it is important to note that most patients were also retained long-term with a mandibular bonded lingual retainer, which something to consider when you debond your next deepbite case, you can find the four version of this article by Danz and colleagues in the October 2014 issue of European Journal of Orthodontics.

Cone Beam Computed Tomography for the Diagnosis of Vertical
Root Fractures: A Systematic Review of the Literature and Meta-Analysis

Corbella S, Del Fabbro M, et al.
Oral Surg Oral Med Oral Pathol Oral Radiol 2014;118:593-602.

December 18, 2015
Dr. Sei-won Jun

[초벌원고]

Cone beam computed tomography certainly has greatly expanded our diagnostic ability in orthodontics but these advances haven’t been limited to our speciality. Vertical root fractures which orginate in the root and then propagate over time alone the vertical axis of the tooth have long been a diagnostic challenge for our dental colleages. Traditionally radiographic identification of a vertical root fracture has been difficult with diagnosis often relying on clinical signs and symptoms. Recently researchers from the University of Milan conducted a systematic review on the effectiveness of CBCT imaging and aiding in vertical root diagnosis. The article is titled "Cone beam computed tomography for the diagnosis of vertical root fractures: a systematic review of the literature and Meta-analysis" and appears in the November 2014 issue of the Oral surgery Oral Medicine Oral Pathology Oral Radiology journal.

[수정원고]

The specific aim of this review was to compare CBCT imaging to conventional periapical radiography for the detection of vertical root fractures in endodontically treated or untreated teeth. The search methodology was typical for a systematic review and the inclusion criteria were set to select articles with human subjects which used CBCT scans to evaluate at least 10 teeth against the reference standard of direct visualization. The search covered published articles up until April 2014 and retrived articles were catagorized as in vivo or in vitro studies and whether or not the tooth was endodontically treated. Further qualification was made based on the voxel size of the CBCT scans. The search resulted in 12 articles been included with 11 of these studies deemed to have a moderate risk of bias. Only 3 of the articles were in vivo studies but these reported significantly higher sensitivity but similar specificity for CBCT scans when compared to periapical radiography. This was particularly true when the voxel size was smaller than 0.2 milimeters. Similar results were found for filled and unfilled teeth, however accuaracy was negatively affected by the presence of obturation material and posts. Due to limitation in the included studies, no conclusions could be formed regarding CBCT scans detecting fractures in teeth when endodontic posts were present. Overall, the authors concluded that compared to periapical radiographs, CBCT scans had similar ability to correctly rule out vertical fractures but were better at detecting a fracture when one was actually present. So there you have it, it seems one would expect CBCT imaging is advantageous compared to traditional radiography especially when high resolutions are used, but I was surprised that in many clinical scenarios such as in teeth with a post and core that CBCT scans did not provide major diagnositc improvement. Also, it is important to keep in mind that this review looks specifically at vertical root fractures and that the conclusions drawn here may not apply to horizontal fractures at teeth often seen following trauma. You can find the complete version of this review article by Corbella et al. in November 2014 issue of the Oral surgery Oral Medicine Oral Pathology Oral Radiology.

Twenty-month follow-up of occlusal caries lesions deemed questionable at baseline

Sonia K. Makhija et al.
J Am Dent Assoc 2014;145:1112-8.

January 8, 2016
Dr. Sung-Ja Kang

[초벌원고]

I am sure you have often seen patients in your practice who present with brown or black occlusal fissures on their teeth that lead you to suspect the presence of caries. These conditions can present initially, during treatment, or debonding. If the teeth with these occlusal lesions do not show any radiographic evidence of caries, what do you do about them? Also, what do your referring pediatric dentist or a general dentist do about this type of lesion?

[수정원고]

In an article titled������Twenty-month follow-up of occlusal caries lesions deemed questionable at baseline������by Sonia Makhija et al, which appeared in the November 2014 issue of the Journal of the American Dental Association, I was surprised to find that there have been few studies regarding the characteristics, management and treatment of this type of lesion which is referred to as questionable occlusal caries. There also appears to be no consensus about how best to manage them. This was the motivation for a study conducted by The National Dental Practice-based Research Network. The purpose of which was to follow 1341 questionable occlusal caries lesions identified in general and pediatric community practice centres.

After the characteristics of these lesions were recorded at baseline, lesion status was again evaluated at 20 months. Of the 1341 questionable occlusal caries lesions examined at baseline, the treatment that was planned for 1033 of these lesions was simple monitoring which consisted of oral hygiene instruction, applying or prescribing fluoride or varnish, or both. The remaining 308 lesions received sealant or invasive therapy which consisted of enameloplasty, preventive resin restoration or full restoration. Of the 1033 lesions for which the treatment plan at baseline was monitoring, 90% also had monitoring as treatment plan at the 20-month follow-up visit, 6% were sealed and 4% received invasive treatment. Of the 116 patients that were treated with invasive procedure at baseline, 84% were acceptable at follow-up, and 4% were not acceptable.

Note for the treatment, information was available for 11% of the patients. The bottom line of this study is that treating a questionable occlusal caries lesion noninvasively appears to be appropriate.

I very much respect the private practitioners who have formed the national dental practice-based research network which has provided data for large samples in clinically relevant studies such as this current study.

It would be interesting to find out if your referring dentists are aware of this study and if the results coincide with their treatment philosophy. You can find this article in the November 2014 issue of the Journal of the American Dental Association.

Perceptions of Dental professionals and Laypeople to Altered Maxillary Incisor Crowding

Ma W, Preston B, et al.
Am J Orthod Dentofacial Orthop 2014;146:579-586.

January 15, 2016
Dr. Seung-weon Lim

[초벌원고]

An article that I recently read reminded me of a question that one of my fellow orthodontic residents asked Dr. Ashy Scibor who was the chairman of the orthodontic department at Georgetown University. My classmate asked to Dr. Scibor what amount of crowding constitutes malocclusion. I will first review the article that reminded me of this question before I give you Dr. Scibor’s answer to the question at the end of this review. The article is titled “Perceptions of Dental Professionals and Laypeople to Altered Maxillary Incisor Crowding” by Wensheng Ma et al. It appeared in Nov. 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics. In this study, the authors photographed maxillary incisors that were ideally aligned under typodont and then digitally altered the alignment of the incisors to varying degrees from 0.5 to 4 mm based on Little’s irregularity index. The altered incisors were then used to replace the actual incisors in the patient’s smile photo. These photos were limited to the patient’s teeth and lips during smile to avoid extraneous variables. The digitally altered smile photos were then presented to four different groups who evaluated them from one to five with one representing the worst incisor irregularity and five, the best incisor alignment.

[수정원고]

The four groups consisted of orthodontists, general dentists, laypeople who had previous orthodontic treatment and laypeople who did not have previous orthodontic treatment. How much maxillary incisor crowding do you think was required to be noticeable? It is varied between the four different groups. Did it vary by which maxillary incisor demonstrated crowding? Did it vary if one or more incisors were crowded? Well, let me tell you the answers to these questions. Orthodontists and general dentists noticed malalignment of one central incisor when the irregularity index reach 1.5mm, where laypeople with or without orthodontic treatment were sensitive to 2mm of crowding. When crowding was limited to the maxillary lateral incisor, the amount of crowding noticed by orthodontists increased by 1.5 to 2mm at which point orthodontists considered initiating treatment. However the same amount of crowding of the lateral incisor was not noticed by general dentists and laypeople. It was interesting to know that laypeople detected 2mm malalignment of the maxillary central incisor, but except the same amount of malalignment for the lateral incisor. The authors concluded that when multiple teeth are involved in crowding, it appeared that the maxillary central incisors were of greater concern to the evaluators than were bilateral maxillary teeth. In another interesting finding, it was noted that all four groups of assessors indicated that one irregular tooth was more noticeable than where two irregular bilateral teeth of the same type. I can’t help but think that this finding might be due to the presence of asymmetry in the smile with just one tooth crowded. The bottom line of this study is that it appears that orthodontists are more perceptive of maxillary incisor irregularities than are general dentists and laypeople and that irregularities of maxillary central incisors are more noticeable in those of maxillary lateral incisors. Additionally, a single maxillary incisor with crowding is more noticeable than two maxillary incisors that have the same amount of crowding. Before I finish, I want to tell you what Dr. Scibor’s answer was to the resident who asked how much crowding constituted malocclusion. He thought for just a minute or so before responding and then simply said it depends on whether it is before or after treatment. Dr. Scibor was a very practical educator.

You can find this article in the Nov. 2014 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

Effects of Tongue Position on Masseter and Temporalis Electromyographic Activity During Swallowing and Maximal Voluntary Clenching: A Cross-Sectional Study.

Valdés C, Astaburuaga F, et al.
J Oral Rehabil 2014;41:881-889. 

January 29, 2016
Dr. Gyu Hyeong Lee

[초벌원고]

A common non-invasive treatment approach for patients with temporomandibular disorders is to monitor and control tongue position as part of overall effort to reduce unnecessary awake parafunctional activity. This is done with the assumption that by maintaining a particular rest position of the tongue, muscle activity will be minimized which ultimately will help control muscle overuse and hopefully reduce muscle related pain. However, as you might be aware considerable conflict exists in the literature as to where exactly is this ideal tongue position. In an attempt to clearify the relationship between tongue position and activity of the muscles of mastication, researchers from the Universiadad De Los Andes in Chile conducted a simple and concise clinical study the result of which I think you will find interesting. The article is titled “Effective tongue position on masseter and temporalis elecrtomyographic activity during swallowing and maximal voluntarily  clenching: a cross-sectional study” and appears in the December 2014 issue of the journal of Oral Rehabilitation.

[수정원고]

The aim of this study was to measure and compare the tonic EMG activity of the temporalis and masseter muscles following placement of the tongue either on the anterior hard palate or in the floor of the mouth during swallowing and during clenching. For this purpose, 30 healthy volunteers between the ages of 18 and 22  with natural dentition and bilateral molar support and no history of orofacial pain or current use of medications were recruited for participation. Masseter and temporalis muscle activity was recorded using EMG surface electrodes placed unilaterally over the head of the muscle. To standardize tongue placement during the EMG recordings for the floor of the mouth position patients were asked to say the word "SUSI". Similarly for the anterior palatal tongue position patients were asked to say the letter N then while maintaining the tongue in the respective positions they were asked to either swallow with light molar contact or clench their teeth as hard as they could for 3 seconds. These exercises and measurements were repeated 3 times for swallowing and twice for clenching with the highest average EMG activity recording being used. Following data analysis the results were quite clear during clenching there was statistically significant lower level activity for both masseter and temporalis muscles when the tongue was positioned in the floor of the mouth compared to when it was positioned to the palate. In contrast, however, during swallowing no significant differences in EMG acivity were found between the two tongue positions. This led the authors to conclude that in healthy pain-free patients, placement of the tongue in the floor of the mouth reduces masticatory muscles activity during clenching.

I was impressed with the results of this study, it seems like a very simple therapeutic option to decrease muscle activity in some patients but shall keep in mind the next time a patient comes and start a day time clenching habits. However as noted by the authors as participants in this study were healthy and symptom-free it will be important to verify these results in patients who regularly suffer from orofacial pain. A full version of this article by Valdés and colleagues can be found in the December 2014 issue of the journal of Oral Rehabilitation.

Clear Elastomeric Modules Staining by Specific Beverages Compromises Esthetics

Cross LQ, Paczko S, et al.
J World Fed Orthod 2014;3:e174-e179.

March 11, 2016
Dr. Seung-weon Lim

[초벌원고]

Many of our patients are likely to have clear or tooth-color ceramic or a polycarbonate plastic brackets to enhance the esthetics of their fixed applience orthodontic treatment. Clear elastomeric modules are often used in these cases to secure the archwire to the brackets. These clear elastic modules are susceptible to staining from certain foods and beverages, compromising the desired esthetics. I'm sure that you had patients return to your office early to have their clear elastomers replaced, because of their dissatisfaction with staining. Are certain beverages more likely to stain the clear elastomeric ties? And are specific brands and elastomers more prone to stain than others? these questions were explored in an article published in the December 2014 Journal of the World Federation of Orthodontist. The paper was written by Lousian Clauss in colleges from Brazil. the investigators want to access the color changes in various clear orthodontic elastomeric modules that were exposed to a number of potentially staining beverages. This was an in vitro investigation of four brands of clear orthodontic elastomeric modules that were manufactured by Dental Morelli, TP Orthodontics, Rocky Mountain Orthodontics, and Dentsply GAC. The elastomers were kept in an artificial saliva bath at 37 degrees centigrade for a four week test period. 3 times weekly, East sample of elastomers was immersed for 15 minutes and 1 of 4 beverages that potentially can cause staining: coffee, cola, black tea and red wine. The coffee and tea solutions were hot at 80 degrees centigrade, and the cola bath was cold at 10 degrees centigrade to simulate real life conditions. One grouping of elastomers was not exposed to the beverages, and remained in the saliva bath for 4 weeks to serve as a control. Changes in elastomeric color were evaluated randomly by two observers with a spectrophotometer. After 4 weeks using the established yellowness index, which has a range of 0 to 100 with the higher values indicating more yellowness, the surface roughness and macro porosity of the bands of elastomers was also assessed with scanning electron microscopy.

[수정원고]

Now after testing results were analyzed statistically, what did the researchers find? The spectral analysis confirmed that all elastomers were made from polyurethane and were formed from an injection molding process. The electron microscopy did show some variation in the degree of macroporosity between brands. The color changes quantified by the spectrophotometer after immersion were significant. And the greatest discoloration was found in the coffee group, followed by red wine, then black tea, and lastly a mild discoloration was observed in a cola grop. The samples immersed in saliva only exhibited a slight level of yellow staining. The electron microscopy show that coffee immersion cause some surface dissolution of the elastomeric modules, that was not observed in the other samples. Even though the elastomers were a similar chemical composition, there were significant differences found in standing between the brands. The Morelli elastomer show the highest degree of yellow discoloration and the GAC the least. Morelli elastomers, however, discolored the least with red wine, and TP elastomers the most. The TP orthodontic module properties and characteristics were at least affected overall by the types of beverages used. The auther suggested that the yellow standing observed in this study was the result of the fixation of food pigments to the elastomers, and their gradual oxidative degradation. The bottom line of this investigation is that discoloration of clear orthodontic Alaska American modules from the exposure of beverages with high pigment content can compromise of appliance’s esthetics. Specific beverages such as coffee can generate more color change than other tests and beverages and some elastomeric brands are more susceptible to sustaining. The results in this study provides useful information to share with our esthetic bracketed patients on what beverages to avoid to minimize color changes in there clear elastomeric ties. This study also provides information on specific brand susceptibility to beverage standing that also may be helpful to the clinician. I agree with the author suggestion that additional brands should be tested and in vivo studies performed to provide additional information on this topic. If you're interested in the complete article you can find it in the December 2014 issue of the Journal of the World Federation of Orthodontists.

PT Shows Good Short-Team Success for OSA

de Vries GE, Hoekema A, et al.
J Clin Sleep Med 2015;11:131-137.

March 18, 2016
Zhang Fan

[초벌원고]

Surely the majority of you are well aware the uses of mandibular advancing devices for the treatment of obstructive sleep apnea. However, a less commonly used form of treatment is positional therapy, which takes advantage of the fact that for most of patients their OSA is worse when they are lying on their back. This form of treatment involves the wearing of some sort of band across the torso, the position of hard cushion or similarly firm object in the middle of the back, between the shoulder blades. The idea here is that of the patient rolls to the supine position during sleep, then the object worn on their back will make it uncomfortable to the point where they were either avoid that position or roll over to their side and continue sleeping.

[수정원고]

Recently, researchers from the University of Groningen, in the Netherlands, published the largest study today to exam the effectiveness and long term compliance of positional therapy. The article is titled "Usage of positional therapy in adults with obstructive sleep apnea", and appears in the January issue of Journal of Clinical Sleep Medicine. For this retrospective observational study, 40 patients diagnosed with positional OSA, who chose to use positional therapy as their primary treatment, were recruited for participation. The patients had a baseline and then a follow up at-home sleep study wearing positioner after 3 months to assess the treatment effectiveness. The long term compliance was determined via telephone interview after at least 6 months of treatment. For their results, the authors reported that overall the positional therapy was considered successful in 68% of the patients, and effectively reduced both the time spent in supine position and median AHI. In term of compliance, however, after an average follow up period of 13 months, only 38% of the patients were still regularly using positional therapy. These lead the authors to conclude that in the short term, positional therapy is an easy method to treat most patients with positional obstructive sleep apnea showing significant reductions in AHI. Unfortunately, long term compliance is low and close follow up of patients on positional therapy with regard to their compliance is necessary.

I think that the study successfully serve to demonstrate the potential with positional therapy. However, despite showing good levels of effectiveness similar to that of oral appliances, for a variety potential reasons, the long-term compliance with positional therapy is quite poor. It should also be pointed out as treatment compliance with subjectively assessed via self-reporting by the patient, it is possible that the already low levels of use may in fact be overestimated.

You can find the complete version of this article by de Vries et al. in January 2015 issue of the Journal of Clinical Sleep Medicine.

New Embedded Microsensors Objectively Assess Appliance Wear Time

Schafer et al.
Eur J Orthod 2015;37:73-80.

March 25, 2016
Dr. Ji kwon kim

[초벌원고]

Patient compliance has, and likely always will be a challenge to optimal orthodontic care. Unfortunately, when treatment with removable appliances does not proceed as planned, often we are left, wondering if it is inadequate wear-time, appliance design, or physiological factors of the patient that are to blame. Recently, very small electronic sensors, which are not much larger than a watch battery, have been developed. These sensors are designed to be embedded inside the surface of acrylic appliances and record wear-time as when the ambient temperature is within the normal physiological range for the oral cavity. In the February 2015 issue of the European Journal of Orthodontics, researchers from Germany reported their initial findings with one such device in an article titled, "Quantifying patient adherence during active orthodontic treatment with removable appliances using microelectronic wear-time documentation." As the title suggests, the aim of this study was to quantify patient adherence for the first three months of treatment with removable appliances and to evaluate any associations between wear-times and the factors of age, gender, type of device, and location of treatment. For the study, the authors recruited 141 healthy patients ranging in age from 7 to 15 were treated in 4 separate orthodontic clinics in and around Tübingen, Germany. Patients were prescribed either a functional appliance or maxillary expansion plate that was embedded with a temperature sensitive sensor. The sensor measured ambient temperature at 15 minute intervals and stored the data internally. Then, at subsequent check-up appointment, the data was downloaded for processing and transformed into wear and non-wear times according to date and time. All patients were asked to wear their appliance for minimum of 15 hours daily, and the study period consisted of the first three months of treatment for each patient. Following data analysis, the authors reported that the average wear-time for all patients was 9.7 hours per day with only 7.8 percent of patients meeting the prescribed daily 15 hours of wear.

[수정원고]

Female patients wore their appliances a little over an hour a day longer than male patients, and wear-times decreased with increasing age. The authors reported that patients aged between 7 and 9 wore their appliances 3 and half more hours per day than patients between the ages of 13 and 15. Interestingly, the patients from one of the clinical sites had average wear-times 5 hours longer than the other three sites. For the study, the authors concluded that the daily average wear-time of active removable appliances can be objectively recorded using these embedded sensors and that when assessed, wear-time was significantly lower than the amount of time prescribed by the orthodontist. This was an interesting study with result in line with what our clinical experience suggests: that most patients do not wear their appliances for the prescribed amount of time. Also, it is important to know that this study was conducted during the first three months of treatment, and so the relatively modest levels of wear time might be expected to decrease as patients progress to more and more time in treatment. Currently, these sensors cost around 35 dollars, and so I look forward the time when these electronic monitors are more widely distributed and more inexpensive to allow for everyday use. You can find the complete version of this article by Schäfer et al. in the February 2015 issue of the European Journal of Orthodontics.

Patient-Specific Factors Determine Which Appliance Is Best for Crossbite Correction

Wiedel AP, Bonedemark L
Eur J Ortho 2015, 37(April): 123-127

April 01, 2016
Dr. Hussein Al-Jawad

[초벌원고]

When a young patient in the mixed dentition presents to your office with an anterior crossbite, how do you decide on the method on which you will correct the problem. I’d like to share with you a recent study published in the European Journal of Orthodontics that may help you form your decision the next time you encounter such a patient in practice. The article is titled “Fixed versus Removable Orthodontic Appliances to Correct Anterior Crossbite in the mixed dentition-A Randomized controlled Trial” And was written by researchers at Malmö University in Sweden. The aim of the study was to assess and compare the effectiveness of fixed and removable orthodontic appliances in the correction of anterior corssbites resulting in functional shifts in the mixed dentition.

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The study protocol consisted of recruiting patients in the mixed dentition with at least 1 maxillary incisor in crossbite causing a functional shift who also had less than 5 mm of maxillary dental crowding and an ANB angle of greater than 0 presented to the university Orthodontic clinic over a 5 year period. A total of 62 consenting patients were randomly assigned to treatment with either the fixed or removable appliance. The fixed group was treated with 022 slot metal twin brackets bonded to the maxillary incisors and usually 4 additional maxillary teeth. the arch wire sequence used was 16 round niti followed by 19 x 25 NiTi, then 19 x 25 stainless steel and the bite was opened by bonding composite to the occlusal surfaces of the mandibular second primary molars. The removable appliance consisted of an acrylic plate with a protrusion spring for each incisor in crossbite, occlusal coverage of the posterior teeth with the acrylic, a midline expansion screw and stainless steel clasps on the posterior teeth. The appliance was instructed to be worn full time except for eating and while brushing. Patients in both groups were seen monthly for adjustments and once the crossbite was corrected, their respective appliances were kept in place for 3 months to serve as a passive retainer. Between group analyses at baseline showed that gender distribution and the number of teeth in crosssbite were the same between groups though the fixed appliance group was on average 1 year older. For the results at the end of the clinical trial, the authors reported that all patients were successfully treated except for 1 patient in the removable group who could not tolerate the removable appliance. In comparison of clinical outcomes the average treatment duration of 5.5 months for the fixed group was significantly less than the 6.9 months on average for the removable group. The fixed group also had significantly greater increases in both overjet and incisor alignment. However the authors stated that these differences were largely clinically insignificant on average and concluded that both removable and fixed appliances are equally effective in treating anterior crossbites in the mixed dentition.

This was a very well designed and conducted study though the outcome is well-known to experienced clinicians. Ultimately it will be patient specific factor such as teeth calcification risk and anticipated compliance that will guide the decision on which appliance to use. Though I will look forward to a cost effectiveness comparison between the fixed and removable options used in the study. The complete version of this article by Wedel and Bondemark can be found in the April 2015 issue of the European Journal of Orthodontics.

Clinical Examination Provides Poor OSA Diagnosis

Mitchell RB, Garetz S, et al.
JAMA Otolaryngol Head Neck Surg 2015;141:130-136

April 08, 2016
Dr. Gyu-hyeong Lee

[초벌원고]

I’d like to share with you now an interesting paper from the otolaryngology literature relating to obstructive sleep apnea in children. The paper is titled "The use of clinical parameters to predict obstructive sleep apnea syndrome severity in children" and appears in the February 2015 issue of the journal of the American Medical Association Otolaryngology Head & Neck Surgery.

[수정원고]

The question posed by this paper and that is "if a combination of factors including demographics, physical examination findings and questionnaires can predict OSA severity in children" is an important one for orthodontists as we should be aware of the signs and symptoms of this disease in our own patient population. Previous studies have found that neither a single nor combination of clinical parameters can distinguish primary snoring from obstructive sleep apnea, therefore interest has now shifted toward the severity of OSA can be predicted clinically. The data for this study comes from the childhood adenotonsillectomy trial or CHAT study which was a multicenter single blinded randomized controlled trial conducted at 6 academic sleep centers. The trial recruited 453 otherwise healthy children between the ages of 5 and 10 suspected of obstructive sleep apnea. 52% of the patients were female, 55% were African American and 33% were obese. All children underwent a clinical examination and subsequent overnight hospital based sleep study and care givers completed a series of validated questionnaires pertaining to sleep related quality of life and day time symptoms. The outcome of the PSG studies were then assessed and related to the various clinical data through linear and logistic regression analysis. The results of the trial found that the scores from the OSA teen and PSQ questionnaires as well as body mass index and ethnicity were all associated with more severe OSA. However the proportion of variance of disease severity explained by these variables was less than 3% of note both palate position and tonsiller size provided little information on OSA severity. From these results, the authors concluded that the weak associations described indicate that traditional clinical features or common questionnaires cannot predictably discriminate different levels of OSA severity. I found these findings quite interesting and somewhat counter intuitive,  however most children with different levels of OSA severity had similar examination findings including tonsil size and reported day time symptoms. This goes to illustrate the complex pathophysiology of obstructive sleep apnea in children and that clearly the disease severity is influenced by more than just anatomic factors alone. The complete version of this article by Mitchell and colleagues can be found in the February 2015 issue of the journal of the American Medical Association Otolaryngology-Head & Neck Surgery.

Body Size Not Critical Factor in Young Adults' Appraisal of Dentists

Asimakopoulou K, Ignatius J, et al.
J Dent 2015;43(February):235-240

April 15, 2016
Dr. Ji-a Moon

[초벌원고]

Excessive body weight in obesity is a common condition in today's population. Obese individuals are often harshly judged by society including their healthcare providers. Overweight healthcare providers are not immune to these negative social judgments as it is been shown that patients have more confidence and the advice received from none overweight doctors. Does this reported negative perception of overweight healthcare providers also applied to dentists? An article in the February 2015 issue of the Journal of Dentistry focuses on this topic.

[수정원고]

The title of this piece is "The effect of dentists' body-weight size on student social judgments of dental skill and patients' behavioural intentions" The paper's authors from King's College London wanted to investigate if the publics perception of the dental care provider is also influenced by the providers bodyweight. This study was designed as a single blind cross-sectional survey. 302 non-healthcare university students were recruited to participate in the study. The mean age of the participants was 21 years and 87% were female. Photographs of a normal-weight male and female dentist in their late 40s dressed in a white dental tunic and in appropriate setting were digitally modified to appear obese. The two unaltered and two altered images were assessed by a panel of 40 university staff and students who independently validated that the four images were either normal or overweight. The 302 student evaluators randomly use the 5-point scale to assess one, gender-matched photograph as to whether the dentist and the image was competent, professional, caring, had patients' best interests at heart, and was a good dentist. Additionally they noted that they're likely to follow behavioural advice concerning diet and oral hygeine techniques that were given them by the dentist depicted in their photograph. After analysis of the data, what does the researchers find? No significant differences were found between the weight status and gender of the depicted dentists in any of the variables except that normal size dentist images were rated to be slightly more caring than the overweight ones.

The exceptance of advice given by the obese dentist was not significantly different than the advice exceptance likelihood of a normal sized dentist. The authors concluded that the previous reports of negative social judgments about overweight health care providers does not appear to apply to dentists. The findings in the study suggests that obesity does not adversely affect the social judgment ratings made by the public about dentists. They previously reviewed article in Oxstone described the public's preference of an orthodontist who is well groomed and in professional attire. According to this paper, body size is not a critical factor in young adults appraisal of the dentist. So that extra dessert may have an adverse effect on your waistline but it should not affect your patients social judgement of you. It would be helpful if future investigations had additional age groups and educational levels as the evaluators in the study were all university students. It also would be interesting to assess subject seeking orthodontic treatment to determine if these results were applicable. The authors suggested that future investigations should focus on factors that may explain these findings. If you're interested in reviewing the complete report, you can find it in the February 2015 issue of the Journal of Dentistry.

How do SARPE and LeFort Osteotomy Maxillary Expansion Compare

Yao et al.
J Oral Maxillofac Surg 73:499-508, 2015

May 6, 2016
Dr. Youn-ju Kee

[초벌원고]

I’m sure that you’ve faced following circumstance in your practice: your treatment planning  in adult patient with a constricted maxilla and a bilateral posterior crossbite. If one of your treatment objectives was to address the posterior crossbite, how would you accomplish the correction? In non-growing patients with constricted maxillary arches, a surgical approach is often the treatment of choice. The surgical approaches typically are multiple-piece Le Fort osteotomy or a surgically assisted rapid maxillary expansion, SARPE. What are the differences in the results achieved with these two techniques? Previous investigations have used plaster models and two-dimensional posterior-anterior cephalograms to compare these two expansion approaches. In 8th March, 2015 Journal of Oral and Maxillofacial Surgery article, these two expansion procedures were compared. Dr. William Yao and his colleagues at the University of California wanted to utilize cone-beam computed tomography, CBCT, to assess and contrast the skeletal and dental effects of SARPE and multiple-piece Le Fort osteotomy. In this prospective cohort study, subjects with a transverse maxillary deficiency underwent either a SARPE or a multiple-piece Le Fort I osteotomy procedure. Patients that required a surgical expansion of 3-6 mm were deemed candidates for a Le Fort I procedure. Those subjects requiring the maxillary expansion, greater than 6 mm, were considered candidates for SARPE. The other suggested that a Le Fort I procedure is problematic in larger than 6mm maxillary expansions, because of relapse in anatomical limitations. The sample consisted of 13 subjects with the mean age of 28 years, and 7 were females. 9 subjects received a multiple-piece Le Fort I osteotomy, and 4 subjects underwent a SARPE procedure. All patients received 3 CBCT scans, 1 prior to surgery, another within 1 month postoperatively, and another at least 6-months following surgery. Maxillary anterior and posterior skeletal landmarks were identified on the CBCT images and we used to measure skeletal treatment changes. The maxillary canine and first molar widths were identified and used to measure the dental treatment changes. Ratios of dental to skeletal change were calculated to determine the nature of the skeletal and dental width changes in the posterior and anterior maxillary regions. After analyzing the data, what differences did the researchers find and compare in these two expansion techniques? In the posterior maxilla, the mean dental to skeletal expansion ratios for the Le Fort procedure was 0.7, and for the SARPE, 25.2. This indicated a significantly more posterior dental alveolar tipping with the SARPE procedure. In the anterior maxilla, the mean dental to skeletal expansion ratios for the Le Fort procedure was 0.58, and for SARPE, 31.8, again, indicating much more dental alveolar tipping in the SARPE subjects. After a 6-month postoperative interval, both expansion procedures typically had more dental and skeletal relapse and in the same proportions. After 6-month of relapse, the mean net intermolar increase for the SARPE group was 8 mm, and in the Le Fort group, the mean increase was 1.5 mm. After relapse, the mean net posterior skeletal increase was negligible in a SARPE group, and in the Le Fort group, the increase was 2.5 mm. After relapse, the mean anterior dental increase was 4.8 mm in the SARPE group, and in the Le Fort group, 0.6 mm. After relapse, the mean net anterior skeletal increase was 1.5 mm in the SARPE group, and the Le Fort group, 1.4 mm. The authors concluded that the SARPE procedure produced more significant dental and skeletal tipping than found in Le Fort procedure. In the Le Fort group, there was a closer correlation between dental and skeletal changes, which indicated a more bodily separation of the segments. A direct comparison of the two expansion protocols was difficult in this study. Certainly larger samples would be helpful as there were only 4 SARPE subjects included. Also, the SARPE cases were selected to receive greater maxillary expansions than the Le Fort I cases, which may have impacted the results. The SARPE appliances were tooth-borne where they skeletally anchored SARPE changes the nature of the expansion. Longer interval post-treatment evaluations would be helpful to assess this stability of these surgical expansion procedures. With many reports of periodontal deficiency in expanded cases, periodontal evaluations also would be a meaningful addition. This is a well-illustrated paper in the surgical techniques and retention protocols employed for both procedures were clearly described. If interested, the complete article can be found in the Journal of Oral and Maxillofacial Surgery’s March 2015 issue.

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Lack of Molar Occlusion Does Not Increase Risk of Developing TMD Pain

Reissmann DR, Heydecke G, et al.
Clin Oral Invest 2014;18:2159-2169.

May 13, 2016
Dr. Sun Lijun

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Most of us in our profession, I think we are aware of the historical and perhaps to recent debate regarding the relationship between temporomandibular dysfunction and occlusion. Unfortunately, however high quality evidence is often lacking from this discussion. It was with this study in mind that I found the result of recent publication by a national group of researches in Germany quite interesting. The article is titled "The randomized shortened dental arch study : temporomandibular disorder pain" and appeared in the December 2014 issue of the journal Clinical Oral Investigations.

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The study reported on a large multicenter randomized controlled trial which accessed the impact of missing posterior dental support on the risk for temporomandibular disorder pain. Subjects for this trial  were adult patients with all molars missing in one jaw without any signs or symtoms of acute severe TMD pain at the time of enrollment. Patients were consecutively recruited in 14 dental schools across Germany, between years 2001 and 2004 and randomly assigned to receiving their a standardized removable partial denture to replace the missing posterior teeth or to leave edentulous areas unrestored. All patients underwent the same pretrial oral hygiene instruction and any required periodontal or restorative work on the anterior teeth or opposing arch, and then followed up at regular intervals for over 5 years. Data collected at each recall appointment included a TMD pain questionnaire and comprehensive dental and TMJ examination. At the end of the trial, a total of 152 patients, 82 of which were female, with an average age of just under 60 years, had been recruited and included for an analysis. Following the appropriate statistic work up, the authors reported that at that baseline no differences in prevalence of parafunctional habits or demographic, health, or socioeconomic characteristics were present between the treatment or control group.  Overall prevalence of self-reported TMD pain at follow-up visits ranged from around 12 to 18%, however tooth replacement did not change the risk for self-reported TMD pain, mean pain intensity, or clinically verified TMD pain significantly compared to the no tooth replacement group. Based on these data, the authors concluded that replacement of missing posterior teeth with a removable partial denture does not lower the risk of developing TMD pain over the long-term in patients with a shortened dental arch.

This was a sizeable study both in terms of sample size and follow-up period which provides a high-level evidence refuting another often cited link between TMD and occlusion. As noted by the authors, the results of this study do not necessarily imply that missing molars should not be replaced but rather that prevention of future TMD pain should not be a reason to do so. The full version of this study can be found in the December 2014 issue of the journal : Clinical Oral Investigations.

Improved Sleep Habits, Muscle Relaxation Ineffective at Reducing Bruxism

Sarul M, Minch L, et al.
J Oral Rehail 2016;42(April):259-265

May 20, 2016
Dr. Youn-Gyeong Moon

[초벌원고]

Sleep bruxism remains poorly understood phenomenon in dentistry. The researchers are beginning to better define the multifactorial nature of the problem. Psychosocial stress is one such contributing factor that is poorly investigated but often reported by sleep bruxism patients. Recently researchers from the Academic Center for dentistry at the university of Amsterdam thought to investigate the influence of stress on bruxism and published the work in the article titled "Do sleep hygiene measures and progressive muscle relaxation influence sleep bruxism? Report of a randomized controlled trial." The aim of this study was to test the effects of therapies aimed at reducing stress including improved sleep hygiene measures combined with relaxation techniques prior to sleep on sleep bruxism, for this double-blind, parallel, controlled, randomized clinical trial. The authors recruited 16 healthy adult volunteers with self-reported bruxism occuring at least  3 nights per week, and with dental attrition resulting in exposed dentine. The participants underwent baseline hospital based polysomnography to objectively determine bruxing levels. Half of the subjects were then randomly assigned to the treatment group, which consisted of receiving sleep hygiene instructions and relaxation techniques involving progressive muscle relaxation. Participants from this experimental group were instructed to practice  both sleep hygiene measures and the relaxation techniques each night before going to bed. Compliance was monitored  by means of regular phone calls placed at random intervals. Then at the end of the 4-week trial period, a follow-up sleep study was performed on all subjects.  For their results the authors reported that no significant differences in either sleep or bruxism measures were present between the 2 groups at baseline. Following the 4-week trial period similarly no differences were observed in the outcome measures number of bruxing episodes per hour, number of bruxing bursts per hour, or the bruxism time index between the control and treatment group. This let the authors to conclude that within the limitation of the study that a 4-week period of relaxation and sleep hygiene therapy has no effect on sleep bruxism levels. So there we have it. It would appear on the bases of this well-designed and executed study within all be at small sample size. That the techniques discribed unfortunately are not terribly effective at reducing bruxism in susceptible individuals. You can find the full version of this study by Lopez colleagues including the details of the therapies used in the April 2015 issue of the Journal of Oral Rehabilitation.

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Timely Deciduous Tooth Extraction Promotes Eruption of Impacted Canines

Julia Naoumova et al.
Eur J Orthod 2015;209-218.

June 3, 2016
Dr. Ji-kwon Kim

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Impacted maxillary canines occur in around 1~3% of the population twice as frequently in females and males and eighty-five percent of the time the impacted tooth is displaced towards the palate. Though the extraction of the adjacent primary canine is commonly performed in practice, recently the level of evidence supporting this idea has been called into question. In an effort to provide a robust level of evidence for this form of interceptive treatment researchers from the Department of Orthodontics at the University of Gothenburg in Sweden conducted a prospective, randomized clinical trial to evaluate the technique. This study appears in the April 2015 issue of the European journal of orthodontics. In the paper titled "Extraction of the deciduous canine as an interceptive treatment in children with palatal displaced canines."

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Part 1, Shall we extract the deciduous canine or not? The aim of the trial was to evaluate the effect of interceptive extraction of the deciduous canine in terms of rate and time of eruption of the permanent canine as well as a resorption of adjacent teeth. Trial participants included children between the ages of 10 and 13 with unilateral or bilateral palatal displaced canines with retained deciduous canines and no history of orthodontic treatment. At baseline, a total of 67 patients underwent a clinical and CBCT examination and then were randomly assigned to either the treatment or control group. The exam and CBCT scan was repeated at 6 and 12-month follow-up appointments if the permanent canine remained unerupted. The radiographic data was used to assess the positional changes of the permanent canines over time and to qualify any associated root resorption.  The exact timing of the successful canine eruption through gingiva was determined by a patient diary. Further results the authors reported that the treatment and control groups did not differ at baseline in regards to average age or initial canine position. Following the trial significantly more displaced canines erupted and after less time at the extraction sites compared with the untreated control site with the prevalence of eruption of 69 and 39 percent and times to eruption of 15 to 18 months respectively. The treatment group also saw a greater improvements in canine position compared to the controls. However no differences between groups were found in extent of root resorption of adjacent teeth. These results let the authors to conclude that the extraction of the deciduous canine is an effective treatment in patients with palatal displaced canines. This paper is an excellent follow-up to the now classic study by Ericsson and Kurol which first described the success of this technique in terms of the overlap of the impacted canine crown and the root of the lateral incisor on a panoramic film. Using updated CBCT technology and an improved, randomized, controlled, study design, the results of this new research combined with the results of other recent trials have made it abundantly clear that the deciduous canine should be extracted when palatal displaced canines are detected. You can find the complete version of this article by now your mobile and colleagues in April 2015 issue of the European journal of orthodontics

Bone Density Found to Be Associated With Efficiency of Molar Intrusion

Ding WH, Li W, et al.
J Oral Rehabil 2015;42:355-362.

July 1, 2016
Dr. Jun-bo Jeon

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One of the more useful applications for skeletal anchorage is the intrusion of posterior teeth to either address an anterior open bite or correct teeth that have overerupted to develop the loss of an occlusal antagonist. Noting the variability in the rate of molar intrusion reported in the literature, researchers from Che Kiang University in China, recently sought to investigate the factors related to the rate of intrusion in orthodontic patients using mini-screw implants. The study was titled “Comparison of molar intrusion efficiency and bone density by CT in patients with different vertical facial morphology” and was published in the 2015 issue of the Journal of Oral Rehabilitation.

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The purpose of this study was to compare molar intrusion efficiency and bone density in patients with different vertical facial morphologies. For this purpose, the authors selected 36 adult female patients presenting to a university orthodontic clinic with overerupted maxillary first molars. And equal number of hyperdivergent patients defined as having a Frankfort to mandibular plane angle greater than 30 degrees and hypodivergent patients defined as having a Frankfort mandibular plane angle of less than 22 degrees were recruited. In all patients mini-screws were placed on the buccal region between the first and second molars and palatally between the second premolar and first molar. After a 2-week healing period, a 100 gram intrusive force was applied via elastic chains. Multislice helical CT scans of the patients were taken pretreatment and immediately after molar intrusion was deemed complete. With the amount of molar intrusion in determined by the specific clinical indications of the patient. The CT data was then used to calculate the amount of molar intrusions relative to the Frankfort horizontal plane and the mean bone density around the intruded tooth for both time points.

For their results, the authors reported that the average bone density around maxillary first molars was lower in hyperdivergent patients and in hypodivergent patients, while the molars in both groups were intruded approximately 4mm the intrusion took almost two months longer in the hypodivergent patients. The authors therefore concluded that bone density is associated with vertical facial morphology and maxillary molars are easier to intrude in hyperdivergent compared to hypodivergent patients.  One limitation in the design beyond the small sample size was that bone density was only assessed immediately adjacent to the overeruptive molar. I'm curious if the difference is reported were due to differences in bone remodeling following the initial overeruption of the molars or actually apply to the entire jaw. Using the contralateral tooth as a split mouth control may have clarified this relationship. And while the results of this study are quite interesting, it surprises me that the authors were able to obtain approval from their institutional research review board to perform two separate CT scans on these patients solely to assess the molar intrusion. For this reason, I doubt that this study could have been conducted at the University either in Canada or the United States. You could read this article in its entirety in the 2015 issue of the Journal of Oral Rehabilitation.

Water Fluoridation May Prevent Approximately Half of Hospitalizations for Odontogenic Infections

Amir Klivitsky et al.
JADA 2015:146(3):179-183

July 8, 2016
Dr. Ha-yeon Park

[초벌원고]

Fluoridating water supplies has been shown to be effective in reducing the incidence of caries in some communities from 20 to 40 percent. This water fluoridation also reduces the rate of hospitalizations for children and adolescents.  This question was addressed in the study titled "Hospitalizations for dental infections – Optimally versus nonoptimally fluoridated areas in Israel" by Amir Klivitsky et al., which appeared in March 2015 issue of the Journal of the American Dental Association. In this study, the authors compared the rates of hospital admissions for odontogenic infections in children younger than 18 years between 2005 and 2011, in cities in Israel where public water fluoridation concentrations have been consistent since 2004. The cities were divided into two groups based on fluoride concentration in the water; one group had optimally fluoridated cities with ideal fluoridation of 0.7mg/L or more, and a second group of nonoptimally fluoridated cities that had public water fluoridated concentrations 0.5mg/L or less. Thirty-eight municipalities for study and the subjects in both groups were further subdivided on the basis of socioeconomic status. The sample for the study including 1,413 children resided in the 38 municipalities that were studied. After statistical evaluation of the data, it was determined that there was a significantly lower hospitalization rates for odontogenic infections for the cities with higher fluoride concentration. There was no difference in hospitalization duration, which averages 3 days in both groups. When the cities were divided into 3 socioeconomic groups, there was significant difference in hospitalization rates between the optimally fluoridated cities and nonoptimally fluoridated cities in the two lower socioeconomic groups. There was no significant difference between two groups in the higher socioeconomic level. The bottom line of this study is that there is an association between adequacy of water fluoridation and hospitalization due to dental infections among children and adolescents, and this effect is more prominent in populations of lower socioeconomic status. Based on the results of this study, it appears that  fluoridation of community water supplies, which has already been recognized as one of the most significant public health achievements due to its effect of reducing dental caries, may have even greater benefits. You can find this article in the March 2015 issue of the Journal of the American Dental Association.

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Extractions Do Not Adversely Impact Esthetics of Soft Tissue Facial Profile Over Time

Rathod et al.
AJO-DO 2015:147:596-603

July 15, 2016
Dr. Youn-ju Kee

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It seems to me that ever since I was an orthodontic resident at Georgetown University, there has been an extraction versus non extraction debate in orthodontics. I found it quite interesting to see the results of a study that indicated that extraction rates were 30% in 1953, 76% in 1968, and 28% in 1993. Like so many things in our specialty, the extraction non-extraction debate seems to swing on a pendulum from one extreme to the other and back overtime. At present I believe the pendulum has swung towards non extraction treatment due to an increased emphasis on facial esthetics and the concern that extraction treatment needs to flat or dished in profiles. Is this assumption true? An article titled "extraction versus no extraction: Long term facial profile changes" By Anita Bhavnani Rathod et al. Which appeared in the May, 2015 issue of the American Journal of orthodontics and dentofacial orthopedics address this question. This study was designed to determine whether there is a significant difference in the soft tissue facial profiles of adults who did not undergo orthodontic treatment compared with the profiles of patients who had extraction orthodontic treatment as teens. To do this, a sample of 57 untreated subjects were selected from the Bolton-brush study at Case Western University in Cleveland Ohio. This sample focused on subjects who had cephalometric films taken between 10 and 17 years of age and again, after 30 years of age. A second sample of 47 orthodontic patients was selected from a collection of files of patients who were recalled approximately 25 years after their premolar extraction treatment was completed. These patients were treated in one private orthodontic practice. The early and late cephalometric radio graphs for the patients in each of the samples were traced, and changes between the 2 samples were compared. When the comparisons were evaluated and statistically analyzed, the authors reached the following conclusions. Mandibular prognathism increases with age, in both untreated and extraction treated patients. There was no substantive difference in the soft tissue profiles in the 2 samples. But there were differences in the directional changes between the 2 samples. The changes for both samples were greatest for the lips and chin. However, there was a difference in direction of growth for these 2 areas. Changes for the untreated sample occurred mostly in a downward and a forward direction. And for the extraction sample, these changes had more of a forward component, then did the untreated sample. The overall conclusion of the authors is that extraction treatment does not adversely impact soft tissue profile changes over time. I was not surprised by this conclusion, because I assumed that the extraction decision for the treated patients in the extraction sample was based on an individual differential diagnosis. To me, the challenge of making an individual diagnosis and treatment plan for each patient, makes practicing orthodontics interesting, challenging, and worthwhile. My concern today is that I believe orthodontics, is at the extreme end of the pendulum swing, which appears to be endorsing a philosophy of treating virtually every patients non extraction, providing a one size fits all philosophy of treatment. For patients who present with a wide range of individual dental, skeletal and facial variation, simply looking at passers by walking down the street should make this obvious. Hopefully for the benefit of our patients, it will not be too long before the pendulum starts swinging back to a more balanced philosophy of extraction versus non extraction treatment. Results of this study indicate that appropriate extraction orthodontic treatment does not have a negative long term effect on profile. You can find this article in the May, 2015 issue of the American Journal of orthodontics and dentofacial orthopedics.

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Airway Volume Unaffected by Extraction in Majority of Patients

Sarul M, Minch L, et al.
Angle Orthod 2015;85:33-38.

July 22, 2016
Dr. Hyun-Hee Kim

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Over the years, the pros and cons of extractions have been endlessly debated. And more recently, this is extended to include the effects on the upper airway. And you may have asked yourself. Do extractions narrow the upper airway? To answer this question, researchers from SiChuan University in China recently conducted a systematic review of the literature to evaluate the effect of orthodontic extractions on airway dimensions. Their study is titled "The effect of teeth extraction for orthodontic treatment on the upper airway: a systematic review", and appears in the May 2015 issue of the Journal Sleep and Breathing.

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The authors searched several literature databases with relevant terms for studies published up until January 2014. Included studies were either comparative studies or case series comparing healthy orthodontic patients treated with or without extractions and having airway dimension as an outcome measure. The included studies were also assessed in terms of the indications for extractions, which for either anterior-posterior discrepancy, crowding or not specified. The search protocol followed the recommended PRISMA guidelines. Following the screening in review process, seven articles were included in the final analysis and ranged from low to medium quality.

In summarizing the evidence, the authors reported that in three of the four studies of adult patients diagnosed with Class I bimaxillary protrusion and treated with the extraction of four first premolars, airway dimensions were found to decrease. In one study with adult patients treated with four premolar extractions due to crowding, the airway dimensions were found to increase. In three articles involving adolescent patients which did not specify the reasons for extractions, no differences in airway dimensions were found between extraction and non-extraction subjects.

For their conclusions, the authors stated that caution is warranted due to the exceeding heterogeneity and low quality of the included studies. Extractions with large retraction of protrusive anterior teeth could lead to narrowing of the upper airway. While extraction treatment resulting in mesial movement of posterior teeth appears to enlarge the upper airway dimensions. So, the effects of extractions on static airway dimensions appear related to this specific indication for tooth removal. Upper airway dimensions were found both increase and decrease depending on the direction and extent of tooth movement. Unfortunately, this review suffers from the limited quality of the available studies, and fewer still that provide 3D data. A very important point to keep in mind during considering in this review is that this study examined airway dimensions and not function. As airway function during sleep does not correlate closely to awake and upright airway dimensions in most individuals, any assumptions as how these results might apply to sleep disorder breathing may be misguided.

The complete version of this article can be found in the May 2015 issue of the Journal Sleep and Breathing.

Not All Thermoform Material Fit the same

Johal A, et al.
Eur J Orthod 2015;37:503-507.

September 23, 2016
Dr. Youn-ju Kee

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Do you ever use vacuum formed retainers in your practice? If so, I think you will find the results of this next study of particular interest. Vacuum formed or thermoformed retainers as they are also known, are fabricated by heating a thin sheet of plastic which is then forced over a dental cast using either negative or positive pressure to take its final shape. Various materials are available for this purpose, however, little comparative data exists to guide clinicians when choosing among them. In an article titled “The Reliability of Thermoform Retainers: A Laboratory Based Comparative Study”, researchers from The London School of Medicine and Dentistry sought to compare the fit of 4 different commercially available thermoform retainer materials under standardized laboratory conditions. To do this, researchers first fabricated a master cast of a maxillary arch with a number of 1.5-mm diameter ball bearings embedded into the surface of the central incisors and the first molars. This cast was then reproduced 40 times using a silicon impression material. The 40 casts were then distributed equally into 4 groups for each of the materials to be tested, which were ACE, C+, TrueTain and Iconic Clear. A total of 10 thermoform retainers were made using 1mm thick sheets of each material following the manufacturer’s instructions using a universal pressure-thermoforming machine. To test the accuracy and fit of the retainers, the distances between defined sets of the ball bearings on each of the casts with and without the retainers in place were measured using a digital 3D coordinate measuring machine. The same investigator made all the measurements and repeat measurements were made to determine reliability which was found to be high.

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After data analysis, the authors reported that there was considerable variability in terms of distances measured between the various sets of ball bearings and the 4 materials, however overall, the trend was for C+ material to fit less tightly to the casts compared to the ACE, TrueTain and Iconic Clear groups which all tended to contracts slightly against the teeth. Further conclusion, the authors stated that statistically significant differences and dimensions were found amongst Thermoform materials with C+ showing the least tightness of fit. Overall, the differences between materials were very small and it’s unclear if differences of less than 0.5 mm would affect clinical performance. Of course the true test of effectiveness would come from a clinical trial, making the comparison between these materials much more meaningful. The complete version of this article by Johal and colleagues can be found in the October 2015 issue of the European Journal of Orthodontics.

Miniscrews Offer Little Advantage to Herbst Treatment

von Bremen J, et al.
Eur J Orthod;2015;37(October):462-466

September 30, 2016
Dr. Ji-a Moon

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The Herbst appliance has become one of the more popular methods to treat ClassⅡmalocclusion, mainly because it is not reliant on patient’s compliance to be effective. However, clinicians have yet to develop a way to overcome the most significant side effect of this form of treatment: proclination and protrusion of the mandibular anterior teeth. More recently skeletal anchorage has been incorporated into various orthodontic appliances as a means to prevent unwanted dental changes, and I'd like to share with you now one such study that focus specifically on the Herbst appliance. The article is titled “Anchorage Loss Due to Herbst Mechanics - Preventable Through Miniscrews?” and was written by von Bremen Colleagues from the Department of Orthodontics at the University of Giessen in Germany.

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The study aim was to assess the mandibular incisor proclination and protrusion associated with treatment with the Herbst appliance supported by mini-implant anchorage. The study population consisted of 17 consecutive ClassII patients treated in a private practice with the mini-implant-supported Herbst. The protocol used for these patients had a mini-implant which were 8mm long and 1.8mm in diameter placed obliquely between the mandibular second premolar and first molar. Indirect anchorage was added by lacing back the lower axle of the Herbst mechanism to the miniscrew head. The patients were treated concurrently with 0.022” full-fixed appliances, with -6° of lower incisor torque and cinched back 19”X25” stainless steel archwires. For comparison, the authors gathered a control group of 12 subjects selected retrospectively from patients previously treated at the same private practice using the same protocol, except without the miniscrews. Both the treatment and control groups were matched for initial overjet and skeletal maturity and had little to no dental crowding. Outcome data consisted of analysis of pre-and post-treatment lateral cephalograph performed on the same machine and traced by the same clinician.

For the results, the authors reported that the miniscrews of 5 patients in the treatment group had failed, resulting in 12 patients included for final analysis. The initial overjet averaged 7.5mm in both treatment and control group, and all patients were past their pubertal peak of growth based on CVM analysis. Treatment duration with the Herbst appliance averaged 4.5 months for both groups, and all patients were ultimately successfully treated to a Class I molar relationship and normal overjet. In comparing anchorage loss between groups, the only statistically significant difference was an incisor proclination, with the treatment and control groups changing  4.8° and 6.5°, respectively. The authors also pointed out that large individual variation was noted in all of the variables. This lefted to the conclusion that miniscrew anchorage with Herbst appliance treatment resulted in 1.7° less incisor proclination. This difference was not consistent among patients and is unlikely to be of clinical relevance.

I was somewhat disappointed by the results of this study as I often employed Herbst appliance in my practice and would, of course, like to have an effective way to limit the unwanted side effects. The rather high failure rate of the mini-implant reported should also be noted. The authors thought this may be due to the lower teeth being protracted into the implant causing it to fail due to the root proximity this would produce. You can find the complete version of this article by von Bremen colleagues in the October 2015 issue of the European Journal of Orthodontics.

Sleep Bruxism Episodes Linked to Transient Hypoxia

Dumais IE, et al.
J Oral Rehabil 2015;42:810-818

October 14, 2016
Dr. Ji-kwon Kim

[초벌원고]

Though often thought to be associated with obstructive sleep disorders, the exact cause of bruxism during sleep continues to elude our profession. We do know that a complex cascade of physiological events evolving the autonomic nervous system initiates the rhythmic masticatory muscle activity of bruxism. However, the extent to which oxygen saturations level play in event of onset is unclear. Recently, in a clinical study, researchers from the University of Montreal sought to determine if transient changes in oxygen saturation levels are associated with the onset of bruxism movements. They published the results in Journal of Oral Rehabilitation in an article titled “Could transient hypoxia be associated with rhythmic masticatory muscle activity in sleep bruxism in the absence of sleep-disordered breathing? A preliminary report.” For this retrospective study, the clinical data of subjects between ages of 12 and 45 with the idiopathic sleep bruxism who underwent an overnight sleep study over 12-year period was retrieved from university based TMD research clinic. It is important to note that all included subjects had a negative history of sleep disorder breathing or any temporomandibular disorder. The goal here was to not associate bruxism with sleep apnea, but rather to determine specifically if drops in blood oxygen levels initiate bruxing event in healthy individuals. Following the chart review a total of 22 patients including 14 females with an average age of 21 years met the inclusion criteria and were included for analysis. The researchers then examined the sleep study recordings of each patient for bruxing activity, which was scored according to find criteria and the patients were categorized into high or low frequency groups. And the bruxing episodes were characterized as basic, tonic, or mixed. The oxymetry at baseline as well as immediately prior and during each bruxing episode was also calculated. For the result, the researchers reported that all patients displayed normal, average, and minimum oxygen saturation levels for the night. And for many absence of obstructive sleep apnea, they did find however subtle variations in oxygen saturation levels associated with bruxing episodes. In 45% of the patients, oxygen levels decreased only slightly between 0.01 and 1%, while in 27% of the patients levels decreased more significantly between 1 and 2%. These results led to the conclusion that in the small sample of healthy patients, episodes of sleep bruxism show a trend of minor hypoxia before their onset. This was an interesting study, then unfortunately does not clearly identify hypoxia as the cause of bruxism. Overall, the changes in oxygen levels observed with bruxing events were quite small as only 27% of the subjects had a reduction of more than 1%. Perhaps a better interpretation of this findings is that drops in oxygen levels can lead to bruxing events in some, but certainly not all bruxism patients. The complete version of this paper by Dumais and colleagues can be found in November 2015 issue of Journal of Oral Rehabilitation.

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Impacted Canines Associated With Reduced Ridge Dimensions

Tadinada A, et al.
Eur J Orthod 2015;37:596-602.

October 21, 2016
Dr. Gyu-hyeng Lee

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Palatally impacted canines are a common finding in a busy orthodontic practice and so have been the focus of a significant amount of research over the years. However, despite these efforts, the exact etiology of this problem remains elusive. One theory behind palatal impaction of canines is that there is a deficiency in the anterior width of the maxilla which if was quantifiable could lead to a better prediction or treatment of the impacted teeth. This was the focus of a recent article appearing in the December 2015 issue of the European Journal of Orthodontics titled “Evaluation of alveolar bone dimensions in unilateral palatally impacted canines: a cone-beam computed tomographic analysis.”

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The aim of this retrospective split-mouth study was to investigate the vertical and transverse dimensions of alveolar bone associated with palatally impacted maxillary canines. For this, the authors screen the archives of a radiographic imaging center for CBCT scans of orthodontic patients imaged for the evaluation of the ectopic canines. These patients were then further reviewed for cases with unilateral palatal impaction of maxillary canines without a retained primary canine and a contralateral canine being fully erupted. In the end, scans of 39 patients including 23 females met all eligibility criteria and were included for an analysis. These retrieved CBCT scans were first segmented and reconstructed to include 2 fiducial lines to allow for standardized orientation and measurement. Then the buccal palatal width of the alveolar ridge was measured in the sagittal sections at 2, 6 and 10 mm apical to the alveolar crest. The alveolar height was measured from the level of alveolar crest to the floor of the nasal fossa. On the impacted side the measurements were made at the center of the edentulous space and on the non-impacted side was measured at the center of the erupted canine. Two investigators working independently preformed all measurements which were repeated again after a 2 week interval. For the results, the authors reported that the interexaminer reliability for the various measurements ranged from moderate to high. The mean alveolar height and arch perimeter were significantly smaller for the impacted compared to the non-impacted sides. Ridge width was smaller on the impacted side only at 2 mm below the alveolar crest, while no differences between sides were found for ridge width at 6 and 10 mm below the crest. There were no statically significant differences in the distribution of outcomes between genders. These findings led to the conclusion that compared to the non-impacted side, there are significant decreases in alveolar ridge dimensions and in arch perimeter on the side of the palatally impacted maxillary canine. The study, though limited by a relatively small sample size, was able to demonstrate with CBCT data that the palatal impaction of a canine is associated with significant reductions in the alveolar ridge in 3 dimensions. However this finding is rather intuitive as we all know that the alveolar ridge will develop with the eruption of a tooth. I would be more interested in knowing if the impaction is the cause or the result of this reduced bone volume. Hopefully, this more interesting question can be answered with similar studies in the future. The complete version of this article by Tandinada and colleagues can be found in the December 2015 issue of the European Journal of Orthodontics.

Infant Orthopedic Treatment Does Not Improve Maxillary Arch Dimensions

Noverraz RL, et al.
Clin Oral Investig 2015;19:2255-2265.

November  4, 2016
Dr. Jun-bo Jeon

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The treatment of children with cleft lip and palate with infant orthopedics or an appliances used to approximate or passively aligned cleft has been previously advocated as a means of improving the esthetic and functional outcomes of cleft repair. Further purposed advantages include their reduced need for secondary surgeries, and improved feeding and speech development. However, the use of infant orthopedics as by no means unanimous, and the reported benefits are somewhat controversial. With the aim of clarifying the effects of this form of early treatment on children with unilateral cleft lip and palate, researchers from three academic centers in Netherlands developed the DUTCHCLEFT trial. Several research papers have been produced  from the various aspects of trial. The latest appearing in the December 2015 issue of the Journal of Clinical Oral Investigations. The study is titled “Transverse Dental Arch Relationship at 9 and 12 years in Children with Unilateral Cleft Lip and Palate Treated with Infant Orthopedics: A Randomized Clinical Trial”. And as the title suggests, the aim here was to assess the long-term effects of infant orthopedics on maxillary dental arch relationships of children with unilateral cleft lip and palate. As part of this larger DUTCHCLEFT trial, 54 otherwise healthy infants with complete unilateral cleft lip and palate were randomly assigned to receive infant orthopedic treatment in a form of a passive maxillary plate during the first year of life or no treatment. Other than the infant orthopedics, all interventions were standardized and kept the same between groups. Lip surgery was performed at 18 weeks of age, and the soft palate was closed at the age of 52 weeks, at which time the orthopedic treatment was stopped in the treatment group. At around 9 years of age, the hard palate was closed in combination with alveolar bone grafting. For this specific study, the patients were recalled at 9 and 12 years of age, and the transverse and anterior dental arch relationships were assessed on dental casts by calibrated examiners using a segmental scoring system. The results showed that the average duration of appliance used in treatment group was 50 weeks. Some of the patients were lost to follow-up, resulting in 22 controls as well as 22 children in the treatment group, presenting for the 12 year follow-up. At both 9 and 12 year time points, no significant differences in total arch constriction between the groups was found. At cleft side showed a higher frequency and severity of crossbites compared to the non-cleft side in both groups at both 9 and 12 year time points. This let the authors to conclude that transverse and anterior maxillary dental arch relationships at 9 and 12 years of age did not differ between unilateral clef lip and palate children treated with or without infant orthopedics. This excellent study was just a small component of the larger DUTCHCLEFT trial, which has been instrumental in our understanding of the effects of early orthopedic treatment of cleft lip and palate infants. The other studies from this DUTCHCLEFT trial have already shown that infant orthopedics with passive plates does not improve feeding, general body growth, parents satisfaction, esthetic outcome, speech or language development during the first 6 years of life. The full version of this paper by Noverraz and colleagues can be found in the December 2015 issue of the Journal of Clinical Oral Investigations.

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BoneCeramic safe, Therapeutic Alveolar Bone Formation, Ortho Tooth Movement

Ru N, Liu SS, et al.
Am J Orthod Dentofacial Orthop 2016;149:523-532.

March 10, 2017
Dr. Seung-weon Lim

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 Bone grafting is often needed as part of an overall orthodontic treatment plan. This may be due to narrow ridges, into which you may be planning tooth movement, extraction sites that have collapsed or the need for an implant placement in an area of the alveolars that has minimal bone. For a long time the gold standard of graft material for problems like this has been autogenous bone, because it has the viability of transferable osteogenic cells. However, the use of autogenous bone requires a second surgery from the donors site. Patients tend to decline this treatment modality because of the additional discomfort. For this reason, the use of Bio-Oss has been used as a graft material for augmenting alveolar ridges. Bio-Oss is the deprotienized bovine bone material. However Bio-Oss degrades slowly. A new synthetic bone substitute, BoneCeramic, has been used for ridge preservation because it can be readily replaced by regenerative bone. BoneCeramic consists of 60% hydroxyapatite and 40% β-titanium phosphate. After grafting, β-titanium phosphate is rapidly resorbed and completely replaced by regenerative bone. Meanwhile, the hydroxyapatite resorbs slowly and serves as a good matrix scaffold for growth of new blood vessels and attachments of bone forming cells. Bone can be greatly regenerated because BoneCeramic can be totally resorbed and subsequently replaced by host bone in a shorter period of time. While BoneCeramic has been shown to be an acceptable graft material, whether it will hamper orthodontic tooth movement in an augmented area of alveolar ridge is still unknown. This question was addressed in an article titled "BoneCeramic graft regenerates alveolar defects but slows orthodontic tooth movement with less root resorption" by Nan Ru et al, which appeared in the April 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics. In this study, the office used 60 five-week old rats, which were randomly assigned to 3 groups of 20 each. All of the rats had the maxillary left first molar extracted. One group had the extraction space grafted by BoneCeramic, the second with Bio-Oss, and the third was a control that had no grafting after extraction. A nitinol coil spring was used to retract the canines in each group and the amount and rate of retraction was measured over 28 days. When the data was analysed, it was determined that greatest amount of tooth movement was observed in the control group, followed by the Bio-Oss group and the BoneCeramic group, indicating that bone substitute decrease tooth movement rate. It was also documented that grafting of bone substitutions, immediately after extraction, slowed ridge resorption. Bone density increased more in the regions of BoneCeramic grafting compared with Bio-Oss grafting and both grafting methods slowed tooth movement. The authors suggested that for longer periods of tooth movement into the extraction site, BoneCeramic increases bone density and preserves the alveolar ridge for a longer time than does Bio-Oss, and there's no difference in tooth movement rate between BoneCeramic and Bio-Oss at the end of the orthodontic loading cycle. The bottom line of this study is that although BoneCeramic slows orthodontic tooth movement, it has a better osteoconductive potential and produces less root resorption compared with Bio-Oss grafting and naturally recovered extraction sites. You can find this article in the April 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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Fixed Functional Appliances Result in Dental, Not Skeletal Changes

Vasileios F. Zymperdikas, et al.
European Journal of Orthodontics, 2016, 113-126

March 17, 2017
Dr.Hussein Aljawad

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Do you use fixed functional appliances for the treatment of class II patients in your practice? If so, what is the amount of skeletal change that you can expect to achieve using this treatment approach. Let me share with you now a recently published large systematic review that will help you when answering this question. The article is titled “Treatment effects of fixed functional appliances in patients with class II malocclusion: a systematic review and meta-analysis” which was published in the April 2016 issue of the European Journal of Orthodontics. The aim of this study was to consolidate the results of the existing literature to determine the cephalometric changes associated with orthodontic treatment using fixed functional appliances. The authors accessed 18 different electronic databases which were searched for relevant terms for studies published until October 2014. Following Cochrane collaboration guidelines, researchers screened for articles of prospective controlled trials involving class II patients treated with fixed functional appliances compared to untreated class II patients. Two authors independently summarized the data and conducted a meta-analysis to assess the outcome of angular measurements from lateral cephalometric analysis. A key point to make here is that data was based on changes only from the time of functional appliance placement to immediately after its removal. Subsequent subgroup analysis based on patient and appliance related factors was also performed. Ultimately the initial search of the literature and subsequent assessment resulted in 9 studies fulfilling all inclusion criteria. The total combined sample included 244 treated patients with a mean age of 13.5 years compared to a 174 untreated controls averaging just under 13 years of age. The consolidated findings for statistically significant treatment effects were normalized per year and treatment and include an increase in the SNB angle of 0.87 degrees, and a reduction in the SNA and ANB angles of 0.8 and 1.7 degrees, respectively. Dental effects included a reduction in upper incisor proclination just over 7 degrees and proclination of the lower incisor by 8 degrees. There was a wide degree of variation in the treatment effects between patients and appliance designs, however due to significant heterogeneity between studies no definitive recommendations could be drawn. These findings let the authors to conclude that short term treatment effects of fixed functional appliances include little change to skeletal variables but a predictable uprighting of upper maxillary incisors and proclination of mandibular anterior teeth. So there you have it, on the basis of this well conducted review involving a large number of studies, it is clear that fixed functional appliances result in little clinically significant skeletal change, but rather provide treatment effect through dental alveolar changes to the upper and lower dentitions. The complete version of this article by Zymperdikas and colleagues can be found in the April 2016 issue of the European Journal of Orthodontics.  

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Orthognathic Surgery Effective Treatment for Extremely Severe OSA Patients

Reginald H. Goodday et al.
J Oral Maxillofac Surg 2016;74:583-589.

March 24, 2017
Dr. Ji-kwon Kim

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 As many of you know, obstructive sleep apnea can have severe effects on a patient's health and quality of life. Beyond CPAP and mandibular advancement appliances, orthognathic surgery to advance both the mandible and maxilla is quickly becoming a viable third option for some patients with the disease. I'd like to share with you now the findings from a study in the March 2016 issue of the Journal of Oral and Maxillofacial Surgery, titled, “Objective and Subjective Outcomes Following Maxillomandibular Advancement Surgery for Treatment of Patients with Extremely Severe Obstructive Sleep Apnea.” As the title suggests, the aim was to describe the treatment effects of maxillomandibular advancement surgery in a very specific group of patients, which are typically very challenging to treat by conventional means: obese adults with extremely severe obstructive sleep apnea, who on average are having obstructive events twice every minute of sleep. For this retrospective case series, the health records of all patients undergoing the maxillomandibular advancement surgery for treatment of obstructive sleep apnea at a university-affiliated hospital during an 18- year period were reviewed. Eligibility criteria included available pre- and post-surgery polysomnopraphy data and a baseline Apnea-Hypopnea Index, or AHI of at least one hundred. Patients also completed pre- and post-treatment questionnaires regarding amount of CPAP used and subjective symptoms of daytime sleepiness, snoring, and satisfaction with surgical treatment. Following the review, a total of 13 patients including two females with the mean age of 39 years met all eligibility criteria and were included for further analysis. The average pre- and post-operative AHI for the sample was 118 and 16, respectively, though one patient was considered a surgical failure with the post-treatment AHI of 95. Subjective measures of sleepiness and snoring were found to dramatically improve in all patients in whom data was available, and all patients considered the surgery a worthwhile experience. Based on these reports, the authors stated that maxillomandibular advancement for the treatment of the extremely severe obstructive sleep apnea can be a highly successful, one-stage surgery, improving both subjective and objective measures of the disease. Though this paper nicely demonstrates that orthognathic surgery to advance both jaws is generally effective for this patient population, it involves very limited sample size and outcome data. Hopefully, this will stimulate improved record taking and perspective clinical trials by our surgical colleagues to allow for more sophisticated analysis of surgical treatment in the future. The complete version of this article by Reggie, Goodday and colleagues from the Dalhousie University and be found in the March 2016 issue of the Journal of Oral and Maxillofacial Surgery.

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Orthodontic Adhesives Similar to Restorative Materials for Bonded Attachments

Feinberg KB, et al.
J Clin Orthod 2016;50:170-176.

March 31, 2017
Dr. Hyun-min Kim

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For improved tooth movement in treatment with removable aligners, bonded attachments are often required on the facial surface of teeth to provide a purchase point for force application. Have you ever wondered if the type of material used for the attachments matters at all? While many aligner companies offer bonded attachments kits for  purchase, I also have several colleagues who claim great success with whatever adhesive they use for bonding brackets in their fixed cases. This topic was the focus of an article in the JCO from the department of Orthodontics at the University of Alabama at Birmingham, titled “Translucency, Stain Resistance, and Hardness of Composites Used for Invisalign Attachments”. The aim of the study was to determine the best option for attachment material by comparing orthodontic adhesive and restorative composite materials in terms of their esthetic properties and hardness. For this, a total of 5 materials were tested – 2 restorative materials (Filtek Supreme Ultra from 3M and Tetric EvoCeram from Ivoclar) and 3 orthodontic adhesives (LCR and Phase II Dure Cure from Reliance and the common Transbond XT from 3M Unitek). Eight samples of each material were created using a mold to form disks 2 mm thick and 12 mm in diameter, and polymerized according to the manufacturer's instructions using the same curing light. The samples were cured through a flat sheet of aligner attachment template material to simulate the surface texture created in clinical conditions. To test translucency and stain resistance, the samples were measured under standardized conditions with a spectrophotometer before and after being stored for 12 days in a 37℃ staining solution of coffee, tea, and cranberry juice. To evaluate hardness each sample was mounted into a microhardness tester and tested 5 times using a validated protocol.
For the results, the authors reported that the restorative material Filtek Supreme was the hardest and most translucent product tested, although for these qualities, the other remaining materials were deemed clinically similar. In terms of staining, the Transbond XT was the material most susceptible to staining. Two degrees were considered clinically noticeable by the authors. These results led to the conclusions, that while some differences in material properties were found between samples, most of the products tested have clinically acceptable stain resistance and hardness. I thought that the most interesting results of the study was that Tetric EvoCeram, the product sold as part of the Invisalign attachment kit, was not statistically different in terms of stain resistance or hardness from Transbond XT or LCR, 2 commonly used orthodontic adhesives. It also should be pointed out that two other important aspects of bonded attachments, and that is, material cost and the ease of removal at the end of treatment were not part of comparisons made in the study. Hopefully, these qualities can be incorporated in the future clinical trials. The complete version of this article, written by Feinberg et al, can be found the March 2016 issue of the Journal of Clinical Orthodontics.

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Patients’ Pain Reduced by Follow-Up Phone Call

Cozzani M, et al.
Eur J Orthod 2016;38:266-271.

April 7, 2017
Dr. In-sun Choi

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In your orthodontic practice, do you currently have a protocol to follow-up with patients following their bonding appointments? As many of you are aware, along with the phone call, several text messaging options exist to allow for easy communication with patients. Recently, in an article titled “Self-Reported Pain After Orthodontic Treatments: A randomized Controlled Study on the Effects of Two Follow-Up Procedures.” which appears in the June 2016 issue of the European Journal of Orthodontics, researchers from the University of Cagliari in Italy examined the effects of patient communication on reported discomfort. Specifically, they sought to compare two forms of follow-up contact, a text message or a phone call, on patients’ self-reported pain following an initial orthodontic bonding. For this randomized controlled clinical trial, perspective non-extraction orthodontic patients from a university-based orthodontic clinic were recruited for participation. In all, a total of 84 patients averaging 13 years of age were randomly assigned to either the text message, phone call, or control groups. All subjects completed a structured questionnaire relating to socio-demographic characteristics, pain experienced, and the use of analgesics at baseline before the initial orthodontic appointment. As well, the patients and their caregivers were then given the same oral hygiene and care instructions at this bonding appointment. The questionnaire was repeated again 4 hours later, after the initial bonding, and then daily for 7 days. For the intervention groups receiving either the structured text messages or phone calls, these messages and calls simply offered general encouragement and enquired about the patients’ well-being, and they were performed 5 to 7 hours after the initial appointment. Patients were unaware that the text messaging or phone call was part of a study, and the blinded examiner performed all data collection and analysis. As for the results, at baseline, the demographics and pain perception were similar amongst all three groups. Overall, pain peaked at day 1 and decreased gradually over the next several days. On day 1 and day 2, patients in text message and phone call groups reported lower levels of pain from the control group. However, these differences were not statistically significant. However, the phone call group reported significantly lower levels of pain compared to the controls on days 3, 5, and 6, while the text message group reported significantly less pain than controls only on day 6. There was no difference amongst the groups in frequency of analgesic use. These results led the authors to conclude that a telephone call after initial orthodontic bonding may effectively reduce patients’ perception of pain especially from the third day onwards. This well-designed clinical trial provides another great reason to make contact with patients following their initial bonding appointment. Not only does it build patient rapport but also can reduce their reported levels of discomfort and pain. Keep this paper in mind at your next staff meeting as you consider how to handle carecalls to the patients of your practice. The complete version of this article by Cozzani and colleagues can be found in the June 2016 issue of the European Journal of Orthodontics.

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Ozone Augments Remineralization of White Spot Lesions

Samuel SR, Dorai S, et al.
Clin Oral Invest 2016;20:1109-1113.

April 14, 2017
Dr. Lee Gyu-Hyeng

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Ozone as a gas or in water has been previously used as an alternative treatment for carious lesions in dentistry. Ozone is a strong oxidizer and highly bactericidal and acts to open dentinal channels which can enhance remineralization by increasing the perfusion of remineralizing agents. However little work has been done towards determining if these properties could be used to improve the treatment of white spot lesions which are all too common in orthodontic patients. However recently researchers at the Department of Public Health Dentistry in Chennai, India explored this topic in an article titled “Effect of Ozone to Remineralize Initial Enamel Caries: In Situ Study” which appears in the June 2016 issue of the Clinical Oral Investigations. The aim of the study was to evaluate the effects of ozonated water and a remineralizing agent in reversing initial enamel carious lesions. For this in situ study, sample materials were obtained from 30 intact maxillary premolars extracted from healthy orthodontic patients as part of their ortho treatment plan. The crowns of the teeth were sectioned into 4x4 mm area of the buccal surface was isolated by covering the remainder of the crown in an acid resistant varnish. The samples then underwent a demineralizing procedure to create a subsurface carious lesion and then were randomly allocated evenly into 3 groups based on the remineralizing treatment. Group 1 received ozonated water and a 10% nano-hydroxyapatite paste, group 2 received only the 10% nano-hydroxyapatite paste and group 3 served as a control. The specimens were then embedded into the retainers of the 30 orthodontic patients and were then worn for 21-day period. The ozone treatment consisted of running ozonated water directly over the specimens for 1 minute daily. The nano-hydroxyapatite paste was brushed onto the specimens using a finger twice daily for 2 minutes by the patients themselves. Lesion progression was assessed by DIAGNOdent readings taken at baseline, after demineralization, and again after the 21-day study period. The depth of remineralization was then also analyzed with polarized light microscopy. For the results, the researchers reported that the ozone plus nano-hydroxyapatite paste group had significantly lower DIAGNOdent scores and greater remineralization compared to specimens treated with the paste alone or the control group. Even more significantly, the ozone-treated group demonstrated complete remineralization of the lesion as visualized under polarized light microscopy. This led the researchers to conclude that ozone in combination with a remineralizing agent of nano-hydroxyapatite may significantly reverse the progression of white spot lesions. I was impressed by the outcome of this study. While the majority of previous work on ozone treatment has been on cavitated lesions, the findings of this study effectively demonstrates the potential of this noninvasive treatment for use on white spot lesions commonly seen in ortho patients. It should be noted that for this study the application of ozone seemingly acted to improve the effectiveness of the nano-hydroxyapatite paste rather than working as an isolated product. I look forward to further research in the form of clinical trials that hopefully will also assess the effect this form of therapy on white spot lesion appearance. The complete version of this article by Samuel and colleagues can be found in the June 2016 issue of the journal, Clinical Oral Investigations.

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No Mechanical Drawbacks to Flaming Archwire Ends

Faria da Silva1, et al.
Dental Press J Orthod 2016;21:83-88.

May 12, 2017
Dr. Youn-ju Kee

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In your practice, do you or your staff ever flamed the distal-ends of a NiTi archwire? If so, you may find a results of this next article quite interesting. This process of annealing the distal ends by passing them through a flame works by changing the mechanical properties of the wire till allow a permanent bend to be set. However, the extent to which this affects the properties of the remaining length of the nickel titanium  archwire is unknown, and was the focus of the recent article by Faria da Silva and colleagues titled "The influence of Distal-End Heat Treatment on Deflection of Nickel-Titanium Archwire" as you can surmise from the title, the aim of the study was to evaluate the force-deflection behavior of nickel titanium archwires adjacent to the terminal ends submitted to a flaming heat treatment. The study protocol entail selecting 10 archwires of 4 different manufacturers in both 19x25 nickel titanium and 16x22 nickel titanium for analysis. The terminal 28 mm of each end of the samples were cut, with one end being used as a control and the other for the test group providing a total of 80 samples in each group. The last 5 mm of the test samples were subjected to heat treatment by placement in a flame of a standardized temperature and duration of time. The mechanical properties were assessed with a 3-point bending test at 36˚C in a device simulating a premolar bracket and a molar tube at either end of the span. The center section of each wire was first loaded to a deflection of 3.1 mm and then unloaded at a rate of 1.0 mm/min. For the results, The authors reported that as expected, overall the 19x25 NiTi samples displayed higher force levels than the 16x22 NiTi archwires, at all activations. However in comparing the effects of the heat treatment the deflection force at maximum activation and then a deactivation of 1 mm was not significantly different between the test and control groups for either archwire dimension. This led to the conclusion that heat treatment to anneal the terminal ends of a NiTi archwire does not alter the mechanical properties of the adjacent portions of wire. This was an effective and straightforward study demonstrating that there were no negative mechanical effects of flaming the ends of a NiTi archiwire. However despite this, several orthodontic pliers exist which can be used to place cinch-back or small v-stop bends in NiTi wires without the need to play with fire. The complete version of this article by Faria da Silva and colleagues can be found in the February 2016 issue of the Dental Press Journal of Orthodontics.

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New Modified Skeletal-Anchorage, Maxillary-Protraction Technique Tested

Ağlarci C, Esenlik E, Findik Y, et al.
Eur J Orthod 2016;38(June): 313-323.

May 19, 2017
Dr. In-sun Choi

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 I’m sure many of you are familiar with the bone-anchored maxillary protraction or BAMP technique popularized by De Clerck, which has shown dramatic improvements in young patients with maxillary deficiency. Recently, a modification of this technique involving maxillary mini-implants instead of zygomatic mini-plates was reported on in an article in the June 2016 issue of the European Journal of Orthodontics. The article was titled “Comparison of Short-term Effects between Face Mask and Skeletal Anchorage Therapy with Intermaxillary Elastics in Patients with Maxillary Retrognathia.” and was written by a team of researchers from the faculty of dentistry at Sifa University in Turkey. The aim of the study was to analyze the short-term skeletal and dental effects of maxillary protraction with a traditional face mask compared to protraction with Class Ⅲ elastics attached to skeletal anchorage. This study was a clinical trial involving a total of 59 healthy prepubertal Class Ⅲ patients with an ANB angle less than 0⁰ or a Wits measurement of less than 1 mm, positive overbite, and an SN to mandibular plane angle of less than 40⁰. Based on parental preference following the informed consent discussion, the patients were treated either with traditional extraoral face masks or with the modified BAMP technique. The face mask group had an appliance cemented to the maxillary posterior teeth and used protraction elastics delivering 400 g of force directed 30⁰ downward from the occlusal plane. In the skeletal-anchorage group, mini-plates with an extending hook were placed bilaterally in the mandible between the canine and lateral incisor, and mini-implants were placed in the maxilla bucally between the second premolar and first molar. Class Ⅲ interarch elastics with 200 g of force were used on each side in conjunction with a removable appliance to eliminate any anterior crossbite. Patients in both groups were instructed to wear elastics full-time, and any patients reporting less than 14 hours per day of wear were excluded from the final analysis. Treatment was discontinued once 2 mm of overjet was obtained. Lateral cephalographs taken before and immediately after protraction treatment were taken for all patients and analyzed and compared. At the end of the trial, 9 patients failed to complete the protocol due to poor compliance or multiple mini-implant failures resulting in both groups comprising of 25 patients each averaging 11 years in age. The average treatment time was 6 months and 9 months for the face mask and skeletal-anchorage group respectively. Patients in both groups saw significant increases in the mandibular plane angle, SNA, and ANB angles, protrusion of the maxillary anterior teeth, and the reduction of the SNB angle, however, greater amounts of skeletal change occurred in the skeletal-anchorage patients. The main significant treatment difference was that the lower incisor retroclined in the face mask group, but proclined in the skeletal-anchorage group. From this data, the authors concluded that maxillary protraction with elastics from mandibular mini-plates to maxillary mini-implants can effectively treat Class Ⅲ malocclusions through a combination of dental and skeletal effects. Interestingly, this study differed from others using maxillary protraction with skeletal anchorage in that significant amounts of maxillary dental protrusion and mandibular plane opening was observed from the treatment. This may be due to the more anterior position of force application in the maxilla when mini-implants instead of mini-plates are used. Perhaps these greater dental effects are the accepted compromises in avoiding a second surgical flap procedure in the maxilla with this modified technique. The complete version of this paper by Ağlarci et al. can be found in the June 2016 issue of the European Journal of Orthodontics.

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Are There Any Advantages to Lingual vs Buccal Orthodontic Appliances?

Ata-Ali F, et al.
Am J Orthod Dentofacial Orthop 2016;149:820-829

June 2, 2017
Dr. Youn-gyeong Moon

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If you had a patient with debating as to whether she wanted buccal or lingual orthodontic treatment and asked you what the advantages and disadvantages of the two techniques were, what would you tell her. More specifically what would advantages and disadvantages related to pain, caries, eating, speech difficulties, and oral hygiene. An article titled "Adverse Effects of Lingual and Buccal Orthodontic Techniques: A Systematic Review and Meta-Analysis" by Fadi ATa-Ali et al. which appeared in the June 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics addressed this question. To do this, the authors conducted a systematic review and meta-analysis searching electronic databases up to October 2014. When this was done there were 8 articles which met the criteria for being included in the systematic review  and a meta-analysis was made of 6 studies. What do you think the results indicated for this five specific areas that I previously mentioned namely pain, caries, eating difficulties, speech difficulties, and oral hygiene. The bottom line of this study is that the patients treated with the lingual appliances experienced higher levels at pain, speech difficulties, and oral hygiene problem. There were no significant differences for eating and caries risk. This study is another good example of the value of evaluating only studies that meet rigid research requirements. Now if a patient ask you "What are the advantages and disadvantages of lingual versus buccal braces?" you can give them an answer based on research as opposed to just your impressions. By doing so, you are providing the patient with valid informed consent. You can find this article in the June 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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Treating Staff Members as Professionals

Roger P. Levin
Journal of the American Dental Association 2016;147:381

June 16, 2017
Dr. Jun-bo Jeon

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I believe that almost all orthodontists understand that the success of their practice depends heavily on the performance of their staff members. When staff openings occur in an orthodontic practice for clinical positions such as dental assistants and laboratory technicians, or for clerical or administrative positions such as receptionists or practice managers, staff are usually hired because of the specific skills required for these positions. All of these people would become part of professional team which puts many of them in a professional environment, in which they have never been before. Do you treat staff members as professionals? In an article titled “Treat your team as professionals, and they will be.” by Roger P. Levin, which appeared in the May 2016 issue of the Journal of the American Dental Association, Dr. Levin addresses the question of “What can I do to develop a more professional team?" He suggests that many dental professionals may need to rethink how they view their staff members and determine if you are treating them as professionals. He further suggests that all staff members should be seen as either experts or developing experts in their particular area. If you agree that a staff team that conducts themselves as professionals would be a big benefit to your practice, how do you develop professionals amongst your staff? Dr. Levin suggests that you can do this by developing in individual and comprehensive continuing education program for each staff member. If you need to participate in continuing education courses to keep your professional skills up-to-date, why wouldn't your staff members need to do the same? Dr. Levin suggests that if you view your staff members as professionals, you will understand the importance and value of establishing a comprehensive continuing education program for each team member. A commitment to developing team skills in your practice would lead to benefits for the practice. He believes that it will also create a highly motivated team of experts who understand their function in the practice and know how to work independently. It will also free up more of your time to develop to the critical areas of your practice, which are best addressed by you. In this article, Dr. Levin concludes that if you view each member of your team as a professional, it will change your approach to staff training, and lead to a team of highly trained, dedicated professionals who continue to grow in their jobs every year. I believe a common thread of any successful orthodontic practice is excellent communications and self-starting motivated staff members. Thinking of each staff member as a professional may make it easier to achieve this goal. You can find this article in the May 2016 issue of the Journal of the American Dental Association.

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Awareness of Psychosocial Impact Motivates Adult Patients to Seek Orthodontic Tx

Lin F, et al.
Am J Orthod Dentofacial Orthop 2016;150:476-482

September 7, 2017
Dr. Youn-ju Kee

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There is no question that more and more adults are seeking orthodontic treatment. What determines if adults with malocclusion do or do not seek orthodontic treatment? Is there a direct relationship between the severity of malocclusion or the financial status or ability to pay of the patients that determines which adults seek orthodontic treatment? An article titled "Psychosocial Impact of Dental Esthetics Regulates Motivation to Seek Orthodontic Treatment" by Feiou Lin, et al. which appeared in an September 2016 issue of the American Journal of  Orthodontics and Dentofacial Orthopedics address this questions. In this article, the authors identify 2 groups of adults patients aged 18 to 30 years who presented to the department of orthodontics at the Wenzhou medical university in China. Each group contain 202 patients, 1 group consisted of patients who accepted and proceeded with orthodontic treatment and the other group of patients who did not persue orthodontic treatment. The Chinese version of the psychosocial impact of dental esthetics questionnaire was administered to each of the subjects. This standardized questionnaire as 4 subscales consisting of dental self-confidence, psychological impact, social impact, and esthetic concern. The index of treatment need which determine the severity of malocclusion was also administered to each patient. The results of the questionnaire and the index of treatment need were statistically analyzed and I found the results to be very interesting. The answer to the question that I previously asked, about whether persue the orthodontic treatement in adults was related to severity of malocclusion or financial status is no, to both questions. Researchers found that demand for orthodontic treatment is mostly related to psychosocial factors. however, some patients who are not actually aware of the impact of their own oral health, esthetic and needs when attending an orthodontic clinic. There are considerable differences between normality and subjective perceptions of the dental appearance and objective needs for orthodontic treatment. psychological Impact of dental esthetics was weaker in patients who declined orthodontic treatment then in treated patients, it is interesting to know that the dental health component of the index for orthodontic treatment needs did not have any relationship to the severity of the malocclusion. The bottom line of this study is that for participants who sought orthodontic treatment, the esthetic imparments were varyed the psychosocial impact of the dental esthetics increase with the severity of the malocclusion and psychosocial impact of dental esthetics played an impotant role in their seeking treatment. However even participants with severe objetive treatment needs may reject orthodontic treatment if they have little self-awareness of the potential psychosocial impact of dental esthetics. I thought this was an fascinating study, the result appear to indicate the need for orthodontist to educate the adult patients about the psychosocial impact of the dental esthetics related to malocclusion. your practice might also benefit if you and your staff help make adult patients in your practice and your community aware of the psychosocial impact of malocclusion. You can find this article in the September 2016 issue of issue of the American Journal of Orthodontics and Dentofacial Orthopedics  

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Relationship Between Dental Crowding, Mandibular Incisor Proclination Assessed

Yitschaky O, Neuhof MS, et al.
Angle Orthod 2016;86:727-733

September 15, 2017
Dr. Gyu-Hyeng Lee

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  When crowded teeth are aligned without extractions, the dental arch typically expands transversely and/or the incisors protrude with a change in their angle of proclination. Previously, some clinicians have suggested various linear relationships between the alleviation of the mandibular crowding and the resulting increase in the lower incisor proclination. When there is dental crowding in the lower arch, it would be useful to be able to accurately predict the post alignment position of the lower incisors to determine if extractions are more appropriate than nonextraction approach for a functional, healthy, and stable result. In study in the September 2016 issue of the Angle Orthodontists looked at this relationship. The paper was titled “Relationship between dental crowding and mandibular incisor proclination during orthodontic treatment without extraction of permanent mandibular teeth” It was written by Oded Yitschaky and colleagues from Jerusalem, Israel.
  The authors’ objective was to examine the relationship between the amount of pre-alignment mandibular crowding and the post-alignment changes in mandibular incisor proclination and protrusion. The study sample consisted of 96 randomly selected patients with full permanent dentitions who were all treated with nonextraction and without interproximal enamel reduction. The subjects were all treated with either 022 Roth prescription self-ligation or with conventional brackets and the same arch form rectangular arch wires were utilized.
  Lateral cephalograms and plaster models from before and after treatment for measure to assess any changes in crowding, arch dimension, incisor protrusion, and incisor proclination. After analyzing the records, the authors found that for each millimeter of crowding alleviation, the increase in incisor proclination was 0.5 degrees and the increase in incisor of protrusion was 0.2 mm. There were no differences found in the degree of post-treatment incisor proclination between the conventional and the self-ligating bracket patients. The increase in the incisor proclination appears to be multifactorial and not only related to the amount of alleviated crowding during orthodontic treatment.
  The post-treatment incisor position values had a high degree of variability and it was suggested by the authors that the results serve as only a guiding principle rather than a prognostic tool. As discussed in the paper, 38% of these subjects were treated with Class II elastics which were found to have a significant effect on increasing in size of a proclination. The patients also had a post-treatment mean reduction in their Curve of Spee and mean increase in both arch width and arch depth as well. All of these are variables that potentially could alter the amount of incisor proclination and protrusion independent of the treated crowding alleviation.
  Thus, the high degree of variability in the result is understandable and the resulting in signs of position values are only approximate. This study certainly confirms that there is a significant correlation with the orthodontic alleviation of crowding and the increase in incisor proclination and protrusion. Future studies with more homogeneous samples would be helpful to further quantify the magnitude of the incisal changes that occur as a result of orthodontic alignment. If interested, the complete article can be found in the Angle Orthodontists September 2016 issue.

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No Evidence That Class 2 Elastics Produce
More Root Resorption Vs Other Appliances

Janson G, Niederberger A, et al.
Am J Orthod Dentofacial Orthop 2016;150: 585-591.

September 22, 2017
Dr. Seung-weon Lim

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 Something that every orthodontist worries about is the occurrence of root resorption in his or her patients during treatment. The one thing that you can say with confidence about root resorption is that it is multifactorial and due to many different causes. When I am asked at lectures or courses “What causes root resorption?”, my standard response is “you tell me what you think causes root resorption and I will find research somewhere to support your theory.” For a long time, the use of Class II elastics has been considered a potential cause of root resorption during orthodontic treatment. Is this true? A study titled “Root Resorption in Class II Malocclusion Treatment With Class II Elastics” by Guilherme Janson et al which appeared in the October 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics addressed this question. In the study, a sample of 54 consecutively treated patients with Class II Division 1 malocclusions was retrospectively selected from the records of the Bauru Dental School at the University of São Paulo in Brazil. The 54 Class II Division 1 malocclusion patients were all treated without extractions. The sample was divided into two groups of 27 patients each, one of which was treated with Class II elastics and fixed appliances and the second with headgear and fixed appliances. Periapical radiographs of the maxillary and mandibular central and lateral incisors were used to evaluate the amount of root resorption for each patient and the differences were statistically analyzed. The results indicated that there was no statistically significant difference in root resorption between the groups; either for the overall score or for the score of each tooth individually. I should note that special attention was dedicated to having groups with similar characteristics regarding initial age, treatment time, overjet, initial malocclusion severity, final occlusal status, sex distribution and severity of Class II molar relationship since some of these factors could contribute to root resorption. The mean degree of root resorption was 1.14 mm for the two groups and the resorption was predominantly mild to moderate in both groups which is considered clinically acceptable. Half step to full step Class II malocclusions were included in this study and even though the degree of malocclusion was similar between the two groups. I believe it would have been better to limit the study to patients who had a full step Class II malocclusion. Other than this, I believe this was a well-conducted study which provides encouragement for orthodontists who use Class II elastics. You can find this article in the October 2016 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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Stainless Steel Springs Are Effective for Orthodontic Space Closure

Norman NH, et al.
J Orthod 2016;43:176-185

September 29, 2017
Dr. Jun-Bo Jeon

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 Since the development of the straight wire appliance, most orthodontists close spaces by using sliding mechanics. While there have been several different types of force application done by elastic modules, active ligatures, and coil springs, there has been little research carried out into that of effectiveness. Currently, NiTi springs are very popular because of their superelastic properties and remain the assumption that these are superior to other methods. However, stainless steel coil springs are somewhat cheaper and are not so widely used. This was a very interesting paper that evaluated the effectiveness of nickel titanium springs versus stainless steel springs. It was called “Ni-Ti springs versus stainless steel springs: A randomized clinical trial of two methods of space closure” and has recently appeared in the Journal of Orthodontics. The investigators carried out the study to compare the rate of orthodontic space closure when using Ni-Ti and stainless steel coil springs. This was a two-center randomized controlled trial carried out in the U.K. In this study, the investigators enrolled the sample of children who are having fixed appliance treatment requiring space closure. They were randomly allocated to receive treatment either by a stainless steel coil spring or Ni-Ti spring. Randomization was carried out by using sealed envelopes and the participants and the operators were blinded to the allocation. They collected the data by taking study cast at the start of space closure and at the end of space closure. They then measured the distance between the canine tip and the buccal groove of the upper first permanent molar with a pair of digital calipers. They carried out relevant statistic analysis at the end of the study. I thought that their result were interesting in that there is no real difference between the rate of space closure between the Ni-Ti spring and the stainless steel spring. However, I did note that they terminated the study early and this meant that almost a quarter of the subjects who enrolled this study were not analyzed. They also pointed out that the stainless steel springs were much cheaper than the Ni-Ti springs and therefore they could be considered more cost effective. Overall I thought that this was an interesting study that was carried out in a real world setting. Either it was also very good to see a common clinical problem that was investigated using randomized trial methodology. I did have some concerns about the loss of follow-up. Particularly as the reason was given that the investigators decided to terminate the study early. This does mean that there is potential loss of power in the study and there is also the potential introduction of bias that may influence the results. This also lead to degree of uncertainty in the data. In summary, I feel this was an interesting study that showed no difference between two techniques, one of which was considered cheaper. However, I do have concerns about the high number of drop-outs and I wonder if we should just consider that this study provides us with useful pilot data which can be used for other investigations.

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Pacifier Use, Thumb Sucking Related to Malocclusion

Giampiero Rossi-Fedele et al.
JADA 2016:147(12):926-934

October 13, 2017
Dr. Ji-Kwon Kim

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 What do you tell your patients or parents of your patients who have young child at home and ask whether or not it is okay to use a pacifier or if they have a thumb sucking habit will this affect their teeth. An article titled Establishing the association between nonnutritive sucking behavior and malocclusions : A systematic review and meta-analysis by Esma J. Doğramacı et al. which appeared in the December 2016 issue of the Journal of American Dental Association studied relationship between pacifiers and thumb sucking related to malocclusion. As the title suggests, to do this the authors performed a systematic review and meta-analysis to address 3 basic questions. The first is what is the risk of developing malocclusion in participants with nonnutritive sucking behavior compared with those without nonnutritive sucking behavior. Two, what is the risk of developing malocclusion between patients with different types of nonnutritive sucking behavior. And three, what is the risk of developing malocclusion in participants with longer duration of nonnutritive sucking behavior compared with those having a shorter duration of nonnutritive sucking behavior. The authors initially identified 569 records through electronic database searches, which was eventually reduced to 15 studies which met the requirements for the systematic review. The need to reduce the initial 569 studies to only 15 is an eye-opening indication of tremendous number of studies published that do not conform to rigorous research standards. On the basis of their review, the authors concluded that when pacifier sucking was compared with digit sucking, children with pacifier were 32% less likely to develop and increase overjet although they were at risk of developing a class II canine relationship. In the primary dentition, an association was found between pacifier sucking and developing posterior cross bite and anterior open bite. In the mixed dentition, when digit sucking was compared to subjects who did not have nonnutritive sucking habit, the authors found that there was no overall difference demonstrated in the development of a class II molar relationship. Although, association existed between digit sucking and posterior cross bite. There was, however, significant association between digit sucking and anterior open bite. Long duration of pacifier sucking was associated with anterior open bite and class II canine relationship in the primary dentition. Longer duration of nonnutritive sucking habit in general was associated with anterior open bite in the primary dentition. The authors also found an increased risk of developing class II canine relationship, posterior cross bite and anterior open bite related to pacifier sucking versus digit sucking in the primary dentition. These results were consistent with findings of longitudinal study that examined sucking habits in children and suggested that digit sucking is preferable habit to pacifier sucking. However, because of the greater risk of developing and increased overjet with digit sucking that was identified in their study, the authors were unable to support digit sucking being less detrimental to dentition. The bottom line is that when comparing pacifier to digit sucking children are less likely to have an increased overjet if they use pacifier. However, they are at greater risk of developing other malocclusions such as class II canine relationship and posterior cross bite. Based on their study, the author suggests that correct clinical advice to parents would be to refrain from nonnutritive sucking in the primary dentition so as to avoid the development of an anterior open bite. For those of you who are parents, I’m sure you know that there are times when infants and young children are constantly crying and screaming that a pacifier is worth its weight in gold to create the peace and quiet to keep mother losing her mind. For this reason, I advised mothers in my practice in situations like this that it was less expensive and easier to correct any malocclusion that develops versus paying for psychiatric treatment to repair any damage to the mother’s mind. You can find this article in the December 2016 issue of the Journal of the American Dental Association.

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Tooth Roots Used for Alveolar Ridge Augmentation

Schwarz F, et al.
J Clin Periodontol 2016;43:797-803

October 20, 2017
Dr. Hyun-Min Kim

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 Tooth dentin has a composition that closely resembles that of bone, and it has previously been reported that autografted dentin has both osteoconductive and osteoinductive properties. It also has been recently demonstrated that healthy extracted roots can be used for localized autografted alveolar ridge augmentations. Now, what about instances where hopelessly periodontally involved teeth are to be extracted could maybe used to augment an alveolar ridge in the same individual? This was the question addressed in an article that was published in the Journal of Clinical Periodontology September 2016 issue. The paper was written by Schwartz and colleagues from Germany and was titled, “Periodontally diseased tooth roots used for lateral alveolar ridge augmentation” The authors’ objective was to evaluate the efficacy of using periodontally diseased tooth roots as autografts in the augmentation of the alveolar ridges for subsequent 2-stage early titanium implants. This was a proof-of-concept study in which periodontal lesions were generated in the maxillary molars of 8 dogs. It’s technique was employed using cotton ligatures that were placed subgingivally in the premolars to initiate periodontal inflammation and bone loss. At the same time, the posterior teeth and surrounding bone were also removed in the mandibular quadrants to create an edentulous area. After 4 to 6 months time interval, the now periodontally involved maxillary premolar teeth typically had a 30% bone loss and were extracted. The crowns of the extracted premolars were removed at the cemento-enamel junction. The remaining roots were then scaled and root planed, and the exposed dental pulps were left intact. The prepared roots were then surgically placed horizontally to augment the edentulous ridge in the mandible of the same animal. Typically, two roots were placed parallel to each other, horizontally on each of the alveolar ridge to be augmented. Autogenous retromolar bone blocks were also harvested and grated on the other ridge to use as comparison to the roots grafts. The roots as well as the retromolar cortical autogenous bone blocks were fixated with screws. After 12 weeks, titanium implants were placed in the both grafted areas and after in additional 3-week healing period, the animals were sacrificed. The crestal ridge with the augmented alveolar area, and the bone-to-implant contact were then assessed histologically. Now, what did the researchers find the premolar root and retromolar autogenous grafts were gradually remodelled with replacement resorption and replaced with newly formed bone. The horizontal alveolar ridge widths were increased markedly. None of the premolar root graft sites were found to be associated with any inflammatory cell infiltrates. Histologically, there was a clear indication of early osteointegration of the titanium implants and the level of bone-to-implant contact was found to be statistically similar in both the root grafts and the retromolar autogenous graft sites. The bottom line of this paper was that periodontally involved root autografts were successfully used and may have the potential to be an alternative to retromolar autografts in alveolar ridge augmentation and preparation for titanium implants. Grafting to augment alveolar ridges prior to implant placement is performed commonly in dentistry. The used of periodontally involved teeth that are to be extracted as a potential for ridge augmentation certainly is appealing. In our non-periodontally involved patients, perhaps third molars that are to be extracted could also be a resource in the augmentation of ridges prior to implant placements. I look forward to additional long-term studies in human subjects to further explore this intriguing grafting approach. If you’d like to read the complete paper an review the procedure in detail, it can be found in the Journal of Clinical Periodontology September 2016 issue.

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Little Risk of Significant Gingival Recession Occuring During Orthodontic Tx

Morris JW, Campbell PM, et al.
Am J Orthod Dentofacial Orthop 2017;151:851-859

March 9, 2018
Dr. Ji-kwon Kim

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 There seems to be a continual question as to whether or not orthodontic treatment promotes the development of gingival recession. There have also been questions related to whether or not protrusion of the mandibular incisors or expansion of the maxillary posterior segments cause gingival recession. An article titled, “Prevalence of Gingival Recession after Orthodontic Tooth Movements” by Jason W.Morris et al, which appeared in the May 2017 issue of the American Journal of Orthodontics and Dentofacial Orthopedics addressed these questions. In this study, the authors evaluated the sample of 205 patients who were obtained from two private practice orthodontists. For each patient, frontal and buccal intraoral photographs, cephalometric radiographs, and patient models were used to evaluate recession at three different time points: namely, at the beginning of treatment, at the end of treatment, and at long-term follow-up which was at least two years after appliances were removed. Recession was measured bilaterally on the mandibular incisors, the maxillary premolars, and the maxillary first molars. Three angular cephalometric measurements were used to record the amount of mandibular incisor proclination during treatment. After statistically evaluating the results of their measurements, the authors came to the following conclusions: only minimal amount of gingival recession were evident immediately after orthodontic treatment. Gingival recession increased between the end of treatment and long-term follow-up. However, the amount of recession was not severe. There was no relationship of mandibular incisor proclination during treatment and to the amount of gingival recession either during or after treatment. There was a weak association between the amount of maxillary expansion during treatment and the amount of post-treatment gingival recession. It was also mentioned that some authors have noted that the final incisor position maybe more closely associated with long-term recession than the amount of proclination during treatment. The results of this study showed no difference in the amount of recession between subjects whose final IMPA was greater than 95 degrees and those whose incisors finished at 95 degrees or less. It was also interesting to note that substantially greater amounts of recession occurred during the post-treatment follow-up period which averaged 15.8 years than during active orthodontic treatment. The article concluded that the increases and recession observed after orthodontic treatment appeared to be largely age-related with similar amounts of recession occurring in untreated subjects. Well, the bottom line of this study is that there doesn't seem to be any relationship between orthodontic treatment, mandibular incisor protrusion, or maxillary posterior expansion and gingival recession, which is good news for orthodontists. It is important to understand that this does not mean that any amount of incisor protrusion or maxillary expansion is acceptable and will not incur periodontal damage because these patients were treated by two private practice orthodontists who are obviously practicing under accepted orthodontic standards. You can find this article in the May 2017 issue of the American Journal of Orthodontics and Dentofacial Orthopedics.

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How Should You Handle Short-Term Unexpected Staff Absences?  

Levin RP.
J Am Dent Assoc 2017;148;349-350.

March 16, 2018
Dr. Insun Choi

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 Most offices are designed to run very efficiently. If there are occasions where staff member will be absent for extended period of time, these situations are usually planned for a well ahead of time, and usually do not create a major problem in the office. It is the short-term unexpected absences of staff members that can create a bigger problem for a well-functioning office. How do you adjust in your office for the unexpected staff absences that occur? In article titled “How to manage short-term staff member absences” by Roger Levin, which appeared in the May 2017 issue of The Journal of the American Dental Association, Dr. Levin addresses this specific question. He notes that most offices have specific plans in place to take care of long-term planned absences such as staff vacations, but often do not have a specific plan for short-term unexpected absences for such things as sickness or emergencies with family members. Dr. Levin suggests that you should develop a plan in your office to manage both scheduled and unscheduled absences. To do this, he suggests that you go through a decision making process such as asking the following questions: How long will the staff member be out? What office operations (clinical, administrative, or management) will be affected? and Can the office function without the staff member during this time? There is a big difference between the few hours and 2 weeks off. If the staff member’s position needs to be covered, what are the options? Internal options include expand part-time hours, cross-train other staff members to take on additional duties. External options would be to call a former team member to fill in, bring in a family member who can handle the position during the absence, or contact a temporary agency. Dr. Levin notes that not all practices have part-time staff members, but if you do, one solution is obviously to extend their hours if they are willing to do that. Another internal solution is cross-training one or two staff members to handle the absent employees’ duties. This is something that is easier to do in the administrative area of a practice, because it is much easier to cross-train administrative staff members versus clinical staff members. If you are fortunate enough to have a family member who has relevant experience, this can be a good solution for a short-term staff absence and if this is not possible, a last step would be contacting a temporary staffing firm, but if you do this, Dr. Levin warns that you need to check out references and reviews, and contact colleges who have used the firm. The bottom line of this article is that you need to develop a variety of training and staffing strategies to manage short-term absences. You can find this article in the May 2017 issue of The Journal of the American Dental Association.

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Herbst Appliance May Cause Condylar Remodeling, but Level of Evidence Is Weak

Souki BQ et al.
Orthod Craniofac Res 2017;20:111-118.

March 22, 2018
Dr. Youn-ju Kee

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  There has been a large amount of research carried out into the methods of action of functional appliances. Most of this studies have been carried out on a retrospective basis and therefore subject to selection bias which results in the true effects of treatment being somewhat exaggerated. However little is known about the effects of fixed functional appliances and really is to rather the bite jumping mechanism has the capacity of stimulating great mandibular growth on forward displacement of the mandible. This new paper published in Orthodontics and Craniofacial Research attempted to shed some light on this question. It was called ‘Three-Dimensional Skeletal Mandibular Changes Associated With Herbst Appliance Treatment’ and the lead author was doctor Souki. This was retrospective study in which the author desired to compare the mandibular skeletal changes in Class II patients treated with a Herbst appliance versus orthopedically untreated Class II controls using a 3D virtual modelling protocol. All patients had been treated in one clinic and they have had routine pre-treatment and post-treatment cone-beam CTs acquired for the purposes of diagnosis in treatment planning. The main inclusion criteria were the patients had Class II division I malocclusion characterized by a full Class II molar relationship. They took 25 patients who received one step mandibular activation with a cantilever Herbst and compare these, with 25 patients in a comparison group the patients in this group had a need for other dental treatments or an orthodontic leveling and alignment teeth without an orthopedic phase. They found at the 2 groups were matched for gender, stage of dental development and the stage of skeletal maturation. When they analyzed the cone-beam CT images they found that there was greater 3-dimensional growth in the Herbst group at the condyle. This was in a region of 3.5 mm superiorly and 2 mm posteriorly. I may concluded overall, that there was significant mandibular forward displacement in the Herbst appliance group. I thought this was interesting paper however we do need to remember that this was retrospective study and there was a tendency for the data to over exaggerate the effects of treatment. This is because of selection bias and the allocation of treatment was not random. What of my other concerns was they present the large amount of data and subjected this data to multiple comparisons in a form of simple univariate statistics. There is a risk that in carrying out this type of analysis that there was tendency to find false positive results which could have been occurred simply by chance. They did not take this into a count within the statistic analysis plan. However the supreme post color mapping that they carried out did provide us with some useful information. I may certainly act as a pointer to further research. My overall feeling is this study doesn’t really provide us with useful information that should influence at clinical practice because of the flaws in the study design and the statistically analysis. However it does provide us with some information that maybe use to plan future studies in this area.

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MAR Algorithms Reduce Noise Around Metal Restorative Materials in CBCT Images

Polyane Mazucatto Queiroz, DDS, et al.
Am J Orthod Dentofacial Orthop 2017;123:729-734.

March 30, 2018
Dr. Jin-an Jung

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  Cone beam computed tomography (CBCT) is rapidly becoming the imaging standard for orthodontic practices in the United States. The ability to visualize teeth and bone as well as some soft tissue structures is unmatched by plain film radiography. What has made this possible is an increase in reliable and inexpensive computing power. Without the rapid ability to process the hundreds of images, a CBCT image is comprised of this technology might never be used. In development of computer algorithms that process the data and turned it into a visual form are sophisticated but one thing they all have in common is difficulty in interpreting data that is distorted by the presence of metallic restorations such as crowns or amalgam restoratives. Computer algorithms that mitigate these artifacts are necessary to produce reliable distortion-free images for clinical use.
The authors of this study discussed the development of metal artifact reduction or MAR algorithms, but the gold producing artifacts will not sacrifice diagnostic quality. To study these algorithms, the author's devised a method were custom-made imaging phantoms were prepared with cylindrical dental materials embedded within the phantoms.
The phantoms them were made of a self curing acrylic resin in the restoration analogs were different sizes and materials. For one phantom the authors embedded cylinders made of silver amalgam and for the other, the author used copper-aluminum alloy. The cylinders were in fixed diameter 5.4 mm in fixed height also 5.4 mm. The cylinders in each of the phantoms were arranged in the triangular shape. For this study, the authors used the Picasso-Trio CBCT machine made by Vatech. For exposure the unit was adjusted for 80 kvp and 3.7 mA exposure for 27 seconds. These exposure parameters were used to obtain 8 scans with different field-of-view (FOV) sizes ranging from 120 x 85 mm down to 50 x 50 mm. They also used 2 voxel sizes; 0.2 mm and 0.3 mm. The scans were performed both with and without the metal reduction algorithm. All images were captured and converted to the DICOM imaging format for analysis. One examiner evaluated all the scans and the data was analyzed two ways with the Friedman test and Dunn test. The authors also performed intraclass correlation test and found that the examiner was highly reliable. According to the results there was a significant reduction of image noise using the metal reduction algorithm. This case, the authors define noise as the percentage of great on variability around the metallic cylinders. For both the amalgam and the aluminum-copper alloy cylinders there were statistically significant reductions in noise. Additionally neither field-of-view (FOV) size nor voxel size made any difference. All of the images were less distorted on the metal artifact reduction algorithm was applied. Image processing algorithms are proprietary to the manufacturer of the CBCT machine and computer, but all rely on similar properties.
Metallic object reduction algorithms are most likely also proprietary and different studies on different metallic artifact reduction methods have revealed different results than the ones reported in this study. In the discussion the author cites several studies of different algorithms with poorer results than in this study including the inability to diagnose periodontal problems or root fractures. High resolution with CBCT is produced the smaller voxel sizes. Larger voxel sizes reduce the resolution but are generally faster scans. All the processing power required to reconstruct the three-dimensional image is lower than that required for small voxel sizes. The choice of voxel size is dependent on what the practitioner wants to examine. Very fine details are only visible in smaller voxel sizes. If the results of this study can be extrapolated and applied to other CBCT imaging machines and data processing algorithms and it is possible that there is a reliable method for increasing the resolving power of the image near metallic dental materials and therefore increasing the diagnostic utility of the CBCT scan.

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Occlusal Bite Force, Chewing Efficiency Improve After Surgery in Prognathism

Islam I et al.
Int J Oral Maxillofac Surg 2017;46:746-755.

April 6, 2018
Dr. Mirinae Park

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 All patients who are candidates for orthognathic surgery typically have common goals of achieving and improve the esthetics and jaw function. Enhanced function generally is measured by improvements in occlusal bite force and chewing efficiency. When our prognathic patients undergo a surgical correction, is their jaw function and bite force improved or diminished by the procedure? An article that was published in the International Journal of Oral and Maxillofacial Surgery in June 2017 edition examined this question. The paper was written by Islam, Lim and Wong of Singapore and was titled ‘Changes in bite force after orthognathic surgical correction of mandibular prognathism: a systematic review'. The authors' objective was to determine if the surgical correction of prognathism has an effect on bite force and masticatory efficiency. They performed a systematic search of the literature for clinical studies that measured bite force in adult subjects who had undergone orthognathic surgery for a skeletal Class III malocclusion. After assessing the initially identified 127 articles, 17 papers were selected for inclusion in this review. The selected studies included a total of 697 patients with ages ranging from 15 to 44 years. 532 subjects received a bilateral sagittal split osteotomy, 108 received an intraoral vertical ramus osteotomy, and 24 patients received an extraoral vertical ramus osteotomy. All subjects received a mandibular setback procedure and in 4 of the studies a simultaneous Le fort I maxillary surgical advancement procedure was also performed. Most of the patients also received pre-and post-surgical orthodontic treatment, the records taken in the surgical fixation methods were varied in the reviews studies patients sample. The majority of the studies utilize the Dental Prescale System to measure the subjects bite force. This system consists of pressure sensitive sheets and a computer analysis system to quantify bite force levels. The size of the occlusal contact area and the number of occlusal contact points were generally used in the studies to quantify masticatory efficiency. Now, what were the measured effects on these patients' occlusal function after receiving a surgical procedures. The masticatory efficiency was generally improved at 3 months post-surgically, and this increase in function was significant at 6 months after surgery. The number of occlusal contact points in the size of the occlusal area was increased at 6 months after surgery, and significantly increased at 12 months after surgery. The bite force values for pre-surgical subjects were lower than the nonsurgical controls with Class I occlusions, and the bite force values decreased further during pre-surgical orthodontic treatment. The bite force immediately following surgery remained at the lowest level and then increased 8 weeks to 6 months following surgery. At 2 years following surgery, the bite force increased but not to the Class I nonsurgical control level. The researchers surmised that it may be 3 to 4 years after surgery before the bite force matches the nonsurgical control group bite force. The authors concluded that the measured masticatory efficiency at 3 months after surgery was generally enhanced over pre-surgical levels. Occlusal forces were improved or founded to be lower in corrected prognathic patients, than in normognathic patients even at 2 years after surgery. The investigators reported that masticatory exercises including gum chewing has been shown to improve masticatory efficiency and occlusal bite force following surgery. Post-surgical healing, improved intercuspation, and occlusal settling also are likely to contribute to the gradual post-surgical functional improvements described in this paper.  My take-home message from this paper is that when our prognathic patients are preparing for mandibular setback surgical procedure, we can forewarn them that their bite force may decrease as they undergo pre-surgical orthodontics. But following surgery their chewing efficiency and bite force should improve in the months following surgery. If interested, the complete article can be found in the International Journal of Oral and Maxillofacial Surgery June 2017 issue.

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Anxiety is Associated With Orthodontic Pain Perception

Ireland AJ, Ellis P, et al.
J Orthod 2017;44:3-7.

April 13, 2018
Dr. Hussein Aljawad

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 We are all very aware that one of the most common problems that our patients have is experiencing pain when we adjust their orthodontic appliances. We also know from research into the causes of pain that increasing levels of anxiety are often associated with an increased perception of pain. A new study was published in the Journal of Orthodontics that addressed the issue of trying to find out if there is a relationship between anxiety and orthodontic pain. The paper was called “Chewing gum vs ibuprofen in the management of orthodontic pain, a multi-centre randomized Controlled trial - the effect of anxiety” the leading author was Anthony Ireland. This paper involved the further analysis of data that was collected in a previous study in which they looked at the effect of chewing gum on orthodontic pain. In this study they showed that when an orthodontic patient used chewing gum they took fewer analgesics to manage their pain. In this new paper, they looked to statistical data to measure the effect of anxiety on pain experience. In their study, they had involved 1000 orthodontic patients and randomized them to receive either chewing gum or ibuprofen as a method of reducing their pain. In this part of the study, they gave the patients questionnaires that measured their pain and their level of anxiety and these were completed at the bond up appointment and the first arch wire change. When they looked at their data, 70% of the patients returned their anxiety questionnaires at the of first archwire change appointment. And their analysis showed that for the patients in the ibuprofen group, there was 10-20% increase in the chances of them using ibuprofen for each point increase on the anxiety scale. They concluded therefore that there was a weak association between reported anxiety and pain. Interestingly, the patients who were the more anxious took more ibuprofen. I thought this was an interesting paper which was based on a subset of data from a large clinical trial. The trial had been carried out to a high standard and it provided us with a useful result. I thought the findings from this part of their study were interesting particularly that there was an association between anxiety and pain in the group that had taken ibuprofen. It was interesting also to see that they did not find this effect for the chewing gum group. Unfortunately, they didn’t discuss this finding. Perhaps the chewing gum reduced the anxiety of the patients. We have to consider whether these results have implications for practice and I think that they do. Perhaps we should encourage our patients to reduce gum to reduce their pain. But also, perhaps we should consider providing more information to reduce the anxiety that our patients my feel about their appointments. They could result in a reduction in their pain experience. This could be a simple intervention that is certainly worth trying

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Effectiveness of 2 Types of Fixed Lower Retainers Compared

Schütz-Fransson U, Lindsten R, et al.
Angle Orthod 2017;87:200-208.

April 27, 2018
Dr. Zheng Yuchen

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 Mandibular bonded retainers are commonly utilized following orthodontic tooth movement to help maintain corrected tooth positions. Typically, lower bonded retainers are designed either with a lingual wire bonded to each lower tooth from canine-to-canine or only bonded to the lingual surfaces of the two lower canines. Is one of these retainer designs more effective in holding the corrected mandibular incisor positions long-term? This was the focus of a study published in the March 2017 Angle Orthodontist. The paper was written by Ulrike Schütz-Fransson and her swedish colleagues and was titled “Twelve-year follow-up of mandibular incisor stability: Comparison between two bonded lingual orthodontic retainers”. The sample in this retrospective study consisted of 64 children with class Ⅱ deep bite malocclusions who had completed fixed edge wise orthodontic treatment that involve both dental arches. No enamel interproximal reductions or circumferential supracrestal fiberotomies were performed in any of the cases. 28 patients received a 0.028 round steel wire that was bonded to the lingual surfaces of both mandibular canines and 36 received a 0.0195 twist flex wire that was bonded to the lingual surface of each mandibular tooth from canine-to-canine. The retainers were placed with a similar technique in bonding composite. The fixed retainers were in place for a mean retention period of 2.6 years, and then removed. Approximately two thirds of the cases in both groups were treated with an extraction approach. Dental casts and lateral cephalograms were obtained and measured at four time intervals: immediately before treatment initiation, immediately after active treatment completion, at six years after treatment completion with a mean 3.6 years after retainer removal, and finally, 12 years after treatment completion, which was a mean 9.2 years after retainer removal. The active orthodontic treatment time for these patients typically spanned 2.5 to 3 years. Now, after comparing the two groups, did the researchers find any significant differences between the two retainer types in holding mandibular incisor alignment? That answer is no. In both groups, the mean Little Irregularity Index was approximately 4.6mm prior to treatment. The mean index was reduced to 1.7mm at appliance removal, and then increase to a mean 4.3mm at 12 years following treatment completion. There were no significant differences found in Little’s Irregularity Index, or in the available space for the mandibular incisors between the two groups at the twelve-year post- treatment evaluation. In both groups, the overjet and overbite were reduced with treatment and stayed relatively stable throughout the post-treatment period. In both groups, the intercanine width was maintained during treatment and decreased by a mean 1mm during the post-treatment period. There were no significant intergroup differences cephalometrically found at the four time points. There were no differences found in the mandibular incisor stability between the patients treated with tooth extractions and those without tooth extractions. Retainer bonding failures occurred in approximately one-third of the subjects. The failures typically occurred in the first year, and the failure rates were not significantly different between the two retainer types. The authors concluded that both a canine-to-canine retainer bonded only to the mandibular canines and a twistflex retainer bonded to each lower anterior tooth are equally effective in holding mandibular incisor alignment. Neither of these retainer types prevent the significant relapse of mandibular incisor irregularity and the reduction of available space for mandibular incisors that typically occurs after retainer removal. It was disappointing that after retainer removal and a mean 9-year follow-up that the lower incisors had relapse to approximately 90% of the Little Incisal Irregularity Index pretreatment value. It appears that regardless of the type of fixed lower retainer used in this patient sample, there was significant mandibular anterior relapse following retainer removal. The use of long-term retention appears to be an important aspect in maintaining orthodontically corrected lower incisors. A typically no longer use bonded retainers with braided steel wire that was utilized in some of these patients. This braided steel wire has been shown to be potentially problematic as the wire may bend after placement resulting in unwanted tooth movements. If interested in reviewing the complete article, it can be found in the march 2017 Angle Orthodontist.

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Autotransplantation of Mature Third Molars Appears a Viable Option

Yu HJ, Jia P, et al.
Int J Oral MaxillofacSurg 2017;46:531-538.

May 11, 2018
Dr. Sukcheol Lee

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 Autotransplantation of teeth with immature roots has been reported widely to have a high rate of success. Teeth with mature root development typically require root canal treatment when autotransplanted, and have been reported to have lower success rates than autotransplanted immature teeth. In April 2017 article, published in the journal of Oral Maxillofacial Surgery has some updated information for us on this subject. The paper was titled ‘Autotransplantation of Third Molars With Completely Formed Roots Into Surgically Created Sockets and Fresh Extraction Sockets: A 10-Year Comparative Study’ and which written by Dr. Yu and colleages from China. The researchers wanted to assess the outcomes of mature third molars that were autotransplanted into surgically created sockets and those autotransplanted into fresh extraction sockets. In this prospective study, 65 third molars with completely formed roots were autotransplanted into 60 patients, with an average age of 33 years. The transplants were performed with a standardized procedure by a single surgeon. The procedures were divided into an immediate autotransplantation group consisting of 29 third molars, they were autotransplanted into fresh molar extraction sockets. The second group had delayed autotransplantation of 36 third molars into surgically created sockets either with or without guided bone regeneration. The guided bone regeneration was used in cases where alveolar augmentation of the implant site with bone grafting was indicated. The delay from extraction to transplantation was typically between 15 and 20 minutes for these group of subjects. The patients who were over 20 years of age had their transplanted teeth treated endodontically 2 weeks after transplantation and those under 20 years received endodontics if the transplanted teeth were symptomatic at 2 to 3 months post-transplantation. The subjects always received annual clinical and radiographic examinations for an average follow-up period of 9.9 years. The blinded examinations were performed by a single clinician to assess the periapical healing and periodontal health of the transplants. Survival time was defined as the number of years until the transplant was categorized as an successful, or until the last evaluation. Success is based on periapical healing, periodontal health, and the absence of pathology. Now, what did the researchers find, the means survival rate for the immediate fresh socket transplant group was 93.1%, and for the delayed surgically created socket transplant group the survival rate was 88.9%. The mean survival rate for the immediate fresh socket transplant group was 93.1%, and for the delayed surgically created socket transplant group the survival rate was 88.9%, which was deemed not significantly difference statistically. The survival rate for the guided bone regeneration group was 95% and the non-guided bone regeneration group was 80%, with no signigicant statistical difference between the groups. The frequency of inflammatory root resorption and ankylosis was not significantly different between groups. The risk of transplanted tooth loss outcomes were not influenced by subjects age at the transplantation. But the risk of the transplanted tooth loss increased as the subjects aged. The author summarized, that the autotransplantation of third molars with mature roots is effective for subjects with both fresh extraction sockets and with surgically created sites. They also suggested that when cases are selected and treated properly there was a high long term success rate. Autotransplantation is a viable option to consider in cases where an appropriate transplant tooth and implant site is available. The rate of complications in autotransplanted teeth and cost were reported to be least than prosthetic dental implants. A concern is that previous retrospective studies have reported survival rates in closed apex autotransplant cases at over 90% at 5 years which corresponds with the survival rates reported in this mean 9.9 year trial. But this paper also described survival rates of 50% and lower beyond 10 years. Thus, longer term evaluations of these cases would be helpful in the clinical uses of autotransplanted mature teeth. The surgical management of these cases was well described in this paper. And if you or your surgeon are interested, the complete article can be found in the April, 2017 issue, of the Journal of Oral and Maxillofacial Surgery.

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 CBCT is More Accurate Than PRs in Assessing ERR

Yi J, Sun Y, et al.
Angle Orthod 2017;87:328-337.

May 18, 2018
Dr. Hun-Kyung Park

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  External root resorption is a common concern during orthodontic tooth movement. Root resorption has been shown to be a multifactorial process and it is often difficult to diagnose and to quantify with conventional periapical radiographs. Does the utilization of Cone-beam computed tomography, CBCT enhance our ability to diagnose external root resorption? An article published in the March 2017 Angle Orthodontist may help us answer that question. The paper was written by Jianru Yi and colleagues from Sichuan University in China and was titled “Cone-beam computed tomography versus periapical radiograph for diagnosing external resorption: A systematic review and meta-analysis.” Few authors performed an electronic and manual search of the available databases and relevant journals up until August 2016. Their search was focused on studies assessing the diagnostic accuracy of CBCT imaging and/or periapical radiographs for detecting external root resorption. The results of the identified studies were pulled and analyzed statistically and a meta-analysis was performed to access the diagnostic accuracy of CBCT and periapical radiographs for external root resorption. Now what did the researchers find from the initial retrieved 720 articles? A total of 15 studies were selected for this systematic review. The pooled studies reported on the assessment all over 1,000 CBCT sites and over 1,000 periapical radiograph sites. As you may have suspected CBCT was found to have a significantly higher sensitivity to detecting root resorption than the sensitivity found in periapical radiographs. CBCT was judged by the authors to have the significantly greater diagnostic efficiency than periapical radiographs, no differences were found in the sensitivity between conventional and digital periapical radiographs when compared. This paper's bottom line is that the current literature suggest that CBCT imaging has a higher diagnostic efficacy and detecting external root resorption than periapical radiographs. The authors also suggested that CBCT may provide an accurate imaging method to diagnose and assess the presence of external root resorption in the clinical setting. The significantly higher sensitivity for external root resorption with three-dimensional CBCT when compared to two-dimensional periapical radiographs suggest that CBCT is a more precise imaging method in which to diagnose and assess our patients with suspected external root resorption. One must weigh the potential added cost and radiation burden with CBCT imaging against the enhanced dignostic efficiency of CBCT over conventional periapical radiographs. If interested, the complete article is found in the March 2017 issue of the Angle Orthodontists.

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Articulation Changes More Prominent With HRs Than With VFRs

Wan J, Wang T, et al
Angle Orthod; 2017;87:286-292

June 1, 2018
Dr. Hyun-min Kim

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 Retainers are generally used following active orthodontic treatment to maintain corrected tooth positions after appliance removal. The Hawley retainer (HR) and the vacuum-formed retainer (VFR) are the most common types of removable retainer currently in use. Both retainers have been reported to have an effect on speech when worn particulaly at initial insertion. Does either the HR or the VFR appliance have a greater impact on a patient's speech, and just how long is speech typically affected by a retainer? These were the questions examined in the paper written by Jia Wan and colleagues from Chengdu, China that was published in the March 2017 issue of the Angle Orthodontists. This was a single center, controlled prospective trial with a sample consisting of 20 normal Chinese adults with ages raging from 19 to 29 years. They all had consecutively completed orthodontic treatment and were randomly fitted with either a standard design maxillary and mandibular HRs or VFRs. The Hawleys all had labial bows and the VRFs were trimmed to provide 2 mm of lingual extensions past the gingival margin. The patients were instructed to wear both retainer types full-time except for eating and tooth brushing over the 3-months testing period. A standardized articulation test using the International Phonetic Alphabet was given to each subject at the following time points: before retainer insertion, immediately after retainer insertion, at 24 hours, at 1 week, at 1 month, and at 3 months after initial insertion. The acoustic characteristics of the recorded speech samples were analyzed objectively using a standardized software program and compared. Now did the retainers have an effect on speech after insertion? As you may expect, that answer is yes. The HR group had significant sound distortions in 6 of 9 measured phonetic symbols immediately after insertion. At 1 week, most phonetic symbols were pronounced correctly in the HR group except for the /i/ and /s/ symbols. At 1 month, most HR patients no longer had any measurable speech distortions. The VFR group had significant sound distortions in 4 of 9 of the measured phonetic symbols immediately after insertion. These distortions lasted from 24 hours to 1 week. At 1 month, no VFR subjects had any detectable significant speech distortions. The changes in articulation were significantly more prominent in the HR group as compared to the VFR group, particularly the performance of /i:/, /f/, and /s/ sounds. The authors concluded that sound distortions were found in both the HR group and the VFR group with the phonetic changes more noticeable in the HR group. This paper had detailed diagrams and discussions of the impact that both retainer designs had on each specific phonetic measurement. It would be interesting in future investigations to determine if similar speech effects occurred in native speakers of other languages when retainers are worn. This paper provides support for many of our anecdotal experiences that removable retainers do affect our patients’ speech particularly at initial insertion. We should inform our patients of this typically temporary effect on speech from both of these removable retainer designs. If interested, the article titled “Speech Effects of Hawley and Vacuum-Formed Retainers by Acoustic Analysis: A Single-Center Randomized Controlled Trial" can be found in the March 2017 issue of the Angle Orthodontists.

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 No High-Level Evidence to Underpin Tx Methods of Class II Division 2 Malocclusion

Millett DT, et al.
Cochrane Database Syst Rev 2018;2:CD005972

September 7, 2018
Dr. Hyun-min Kim

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It is well recognized that Cochrane systematic reviews provide some of the highest level of evidence that depends on health care. It was therefore very interesting to see a new systematic review on the treatment of Class II div.2 malocclusion. The paper was called “Orthodontic Treatment for Deep Bite and Retroclined Upper Front Teeth in Children.” The lead author was Dr.Millett and it was published in the Cochrane library. They followed a standard systematic review methodology to evaluate whether non-extraction treatment of Class II div.2 malocclusion produce the result that was any different from no orthodontic treatment or extraction treatment. As this was the Cochrane review, they only included randomized controlled trials and controlled clinical trials in the inclusion criteria. They attempted to evaluate any active intervention using orthodontic appliances and the primary outcome was going to be dental occlusion treatment. There were various secondary outcomes for example the duration of treatment and the number of visits. They carried out classical Cochrane review search in which they evaluated electronic databases followed by hand search of any additional literature. The initial research identified 856 references but when they screened them, they rejected them all because they could not find a single randomized controlled trial or controlled clinical trial that evaluated the treatment for Class II div.2 malocclusion. As a result they could not provide any evidence based guidance to clinicians and patients with respect to the management of this type of malocclusion. Their overall conclusion was that there was no scientific evidence to establish whether orthodontic treatment that does not involve the removal of permanent teeth is better or worse than orthodontic treatment involving the extraction of permanent teeth in children with Class II div.2 malocclusion. Their overall conclusion was unfortunately that more research or even research is needed. I thought it was disappointing to find that this review did not come up with an evidence supporting our treatment of Class II div.2 malocclusion. But in many ways this now lets us consider the role of evidence within the practice of evidence based orthodontics. We all know that when clinical research is available it should outweigh the effect of clinical experience. However, when no research is available that it is clear that treatment should be planned upon clinical experience and this is the case with Class II div.2 malocclusion. I certainly get the impression that most treatment that provide non-extraction bases for this type of condition and perhaps in many ways there is no need to carry out this type of review because clinical experiences seems to be driving treatment that certainly does no harm and certainly provides very good treatment results. However, this is just my personal opinion which of course is the lowest level of evidence.

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SFA May Offer Shorter Tx Time in Class III Nonextraction Surgical Subjects

Yang L et al.
Journal of Oral and Maxillofacial surgery 2017;75:2422-2429.

September 14, 2018
Dr. Ji-Kwon Kim

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Conventional orthognathic surgery for skeletal Class III cases typically involve three orthodontic treatment steps. Initially, a presurgical dental decompensation is performed which usually consists of a proclination of the often retroclined mandibular incisors and a retraction of the maxillary incisors, if extractions have been performed. Next, immediately after the surgical procedure, the dentition is fixated during healing and fixation is followed by a postsurgical finishing phase. Another recently introduced potential option is the surgery-first approach (SFA). In this approach, surgery is performed without or with only limited presurgical orthodontic treatment. This technique has been purported to potentially shorten total treatment time and to eliminate the temporary unesthetic profile changes that result from orthodontic dental decompensations prior to surgery. Thus, this approach in Class III orthognathic surgical cases shorten treatment time, an article written by Le Yang and colleagues from Sun Yat-sen University in China examined this question. The paper was published in the Journal of Oral and Maxillofacial Surgery in press 2017 issue and it’s titled “Does the Surgery-First Approach Produce Better Outcomes in Orthognathic Surgery? A Systematic Review and Meta-Analysis”. The authors assessed the current literature by searching the PubMed and Web of Science databases from 2001 to 2016 for studies that compared the SFA with conventional approach orthognathic surgery. A systematic review and cumulative meta-analysis of all identified studies was then performed by 2 independent investigators to compare the surgery-first and conventional treatment approaches. The recorded outcomes included total and postsurgical treatment  duration, the types of surgical movements, postoperative occlusion, and relapse. Ten retrospective studies with 513 Class III patients were included in this review. None of the selected studies was a randomized controlled trial and the included studies were generally judged to be low quality. The surgical approaches included both 2-jaw and mandibular only procedures. After their review, the investigators reported that relapse of mandible and maxilla was not significantly different between the surgery-first and the conventional approach groups. The surgery-first group had a mean 17-months total treatment time, which was a mean 5.25 months shorter than the conventional group’s mean total treatment time. The postsurgical orthodontic treatment time was significantly shorter in the conventional group as compared to the surgery-first group by a mean 8 months. No significant differences were found in the surgical movements of the mandible and maxilla between the groups. Assessments of the achieved postoperative occlusion and the reported quality of life levels were limited in the reviewed studies. The authors concluded that the surgery-first approach may offer a shorter total treatment time in Class III nonextraction surgical subjets than with a conventional approach. But the surgery-first approach has a typically longer postsurgical orthodontic treatment time when compared to conventional subjects. The authors  recognized that large, well-designed randomized controlled trials are lacking and would be necessary to help clarify the advantages and disadvantages of the surgery-fisrt approach. I also look forward to long-term studies assessing posttreatment occlusion and stability to establish the clinical significance of any differences that are found between the two surgical approaches. A 2013 article by Kim in the Journal of Oral and Maxillofacial Surgery, reported that when extractions are part of the orthodontic treatment plan, the surgery-first total treatment time apparently is not reduced but tends to be longer than in conventional approach subjects. The Kim article also decribed less stable results in the surgery-first group in extracion cases. Another recent paper has been introduced in Peiro et al: article pubilshed in 2017 AJODO reporting that orthognathic surgery improved patients self-assessment quality of life to a simliar level both conventional and and surgery-first groups after surgery completion. And that the conventional group had a decrease in their reported quality of life during the decompensation phase of treatment. If you’re interested in reviewing the complete article, it can be found in the in press 2017 Journal of Oral and Maxillofacial Surgery.

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Patients With History of Orthodontic Tx May Have Decreased Prevalence of Periodontitis

Sim H-Y, et al.
Angle Orthod 2017;87:651-657

September 22, 2018
Dr. Youn-ju Kee

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Patients undergoing fixed orthodontic treatment often have difficulties maintaining their oral hygiene and thus have the potential for increased accumulation of the dental plaque and periodontal disease. We are all challenged by orthodontic patients who struggle with achieving and maintaining a level of oral hygiene that fosters healthy gingival tissues. Do the oral health difficulties typically associated with fixed orthodontics have a lasting effect on the periodontal condition of our treated patients? An article by Hye-Young Sim and colleagues from Seoul Korea that was published in the September 2017 issue of the Angle Orthodontist may help answer that question. In this paper titled “Association between orthodontic treatment and periodontal diseases” the authors wanted to assess the correlation between orthodontic treatment and periodontitis in a representative sample of the South Korean population. They extracted data from the 2012 to 2014 Korean National Health and Nutrition Examination Survey for use in this study. The information utilized in the assessments consisted of patient questionnaires, interviews, physical examinations, blood testing and standardized periodontal evaluations performed by calibrated dentists. Periodontitis was defined as having at least one site with a pocket depth of greater than 3.5 mm. The final sample was composed over 14,000 subjects all 19 years and older. The data was analyzed statistically to examine the relationship between orthodontic treatment and periodontitis. The researchers found that subjects in all age groups who had received orthodontic treatment had a prevalence of periodontitis of 9 percents. This was significantly lower than the 44 percent prevalence, a periodontitis found in the non-orthodontic treatment subjects. A greater prevalence of periodontitis was found in those with greater age, higher body mass index, larger waist cirfomference, higher smoking rates and higher white blood cell counts when compared with the subjects without periodontitis, regardless of their orthodontic treatment history. The orthodontic subjects brush their teeth more often and receive more frequent oral examinations than the non-orthodontic group. The researchers concluded that adult subjects with the history of orthodontic treatment had a decreased prevalence of periodontitis. Additional well-designed longitudinal studies are needed to clarify the associations between orthodontic treatment and the prevalence of periodontitis. In this paper’s discussion, the authors suggested that orthodontic treatment may contribute to a reduction in periodontal disease because of improved tooth alignment and a reduction of occlusal discrepancies. They also stated that the enhanced oral hygiene habits and maintenance that are associated with orthodontic treatment may also contribute to the reduction of the periodontitis prevalence in this previously treated subjects. The results reported in this study underscores the importance of emphasizing and achieving good oral hygiene maintenance throughout and following orthodontic treatment. Periodontal issues are a major factor in chronic orthodontic malpractice litigation and the importance of oral hygiene and periodontal assessments are in the best interest of both the patient and the practitioner. If you are interested in reading the complete article, it can be found in the Angle Orthodontist September 2017 issue.

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Longer Treatment Time Increases Risk of GE in Orthodontic Patients

Pinto AS, Alves LS, et al.
Am J Orthod Dentofacial Orthop 2017;152:477-482.

September 28, 2018
Dr. In-sun Choi

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The relationship between gingival enlargement and orthodontic treatment is not exactly known. Gingival enlargement is different than gingival inflammation, and the effect is to create a gingival pocket or pseudo pocket. Unlike hypertrophic tissue, enlarged or hyperplastic tissue will not respond to changes in hygiene. It is also unclear whether hypertrophic gingiva can progress to hyperplastic gingiva. Lastly, it is not known yet, but the authors are tempted to determine whether there is a relationship between orthodontic treatment length and gingival enlargement. A secondary goal is to see if there’s any correlation between socioeconomic criteria and oral hygiene habits to development of gingival enlargement. This was a cross-sectional study that examined a total of 260 subjects undergoing orthodontic treatment for various length of time. Treatment duration ranged from 1 to 3 years, and the treatment subjects were compared with a control group that was not undergoing orthodontic treatment. The study group was divided into groups based on treatment duration, a 1-year group, a 2-year group, and a 3-year group. Power analysis for the study dictated that each group had to have 65 members. A further subdivision of the study groups was done, separating the subjects in controls into age ranges of less then 15 years old, 15 to 20 years old, and greater than 20 years old. The authors included data that reflected social and economic factors such as the maximum education level of the patients’ mother, and income relative to a minimum wage standard. Tooth brushing and flossing frequency data were also collected. Plaque indices of all subjects were taken, and the gingival enlargement was characterized according to the Seymour index. This index looks primarily two problems. The first is the amount of gingival thickening, and the second is the encroachment of the gingiva on any adjacent teeth. For this study, the authors looked at only the 6 maxillary and mandibular anterior teeth on both buccal and lingual surfaces. There were also the studies showed some interesting trends, including the fact that longer treatment durations were associated with decreased flossing. Longer treatments were also associated with decreased income compared to the minimum wage standards. For gingival enlargement, a change was noted between pre-treatment and 1- and 2-year intervals, but no significant increases were noted from 2 to 3 years. Overall, however, the authors noted that when all factors including socioeconomic status and oral hygiene were considered, orthodontic patients had a 20 to 28 percent greater risk for gingival enlargement as treatment length increased. The propensity for gingival enlargement was also increased in the 20-year and older age group. Some of the oral hygiene habits had a mitigating effect on the incidence of gingival enlargement. So that without good hygiene habits, the outcomes in incidence of gingival enlargement will likely be greater. At specificly with flossing, the sample overall showed decreased rates of flossing in general, and the rate of flossing decreased further with an increased treatment time. So it’s not necessarily likely that flossing would have made an significant impact on the risk for the gingival enlargement. The general conclusion though was that increasing treatment time is associated with an increased risk of gingival enlargement. Since this was a cross-sectional study, the authors suggested that a longitudinal study might reveal other factors that are associated with enlargement. From a treatment perspective, the clinical outcome of gingival enlargement is significant in that reversingly enlargement could necessitate gingivectomy or other periodontal procedures. If specific risk factors could be identified before treatment starts, then it would be good to be able to caution these patients that adjunctive procedures could be necessary at the end of orthodontic treatment. In terms of treatment duration, it would seem that if it is possible to reduce the overall length of treatment, then this would potentially have several positive outcomes not only with the reduction of the likelihood of gingival enlargement but also increased patients’ satisfaction with shorter-duration treatment. As both gingival enlargement and longer treatments have detrimental effects when measured on oral health quality of life scores, reducing both of these should result in an improvement all around.

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Survival Rates of Retainers— VFRs vs BRs

Katherine Forde, et al.
European orthodontic society 2017;1-12.

October 5, 2018
Dr. Jin-an Jung

[초벌원고]

 Most of orthodontist appreciate the disadvantages and advantages of the main types of retainer. However it appears that in general the type of retainer we used depends upon patients choices, nevertheless we do not have much information to inform these choices. This new study which was recently published in the European Journal of Orthodontics provides us with useful information. It was done in 2 parts “Bonded Versus Vacuum-Formed Retainers: A Randomized Controlled Trial Outcomes After 12 Months.” Part 1, the lead author Ms. Dr. Forde. The study team set out to answer the following question. Is are there any difference in the effectiveness on patient perceptions of vacuum-formed retainers and bonded retainers. They carried out to 2-arm parallel group randomized trial with 1:1 allocation. The patients who took part in the study were completing fixed appliance therapy in hospital departments in the north of England. They enrolled 60 patients into the study and they randomly allocated 30 to treatment BRs and 30 to retention with VFRs, the groups are very similar that the start of the study. The main outcomes were the survival of the retainer the amount of retainer measured by Little's index and patient satisfaction which was measured by a questionnaire, the main data was collected at the starto of the study and after 12 months. The results are interesting and they provided a great deal of data. When becomes day terms of main findings these are really the relapse as you measured by Little's index they showed that there was no difference between retainers in relapse in the maxilla, however they showed in the mandible a bonded retainer was more effective than the vacuum formed retainer in preventing relapse. There was no real difference in the survival rates of the different types of maxillary retainers, however, in the mandible the bonded retainers had the higher failure rate. It was interesting to say that the retainer right was almost 15% and this must be considered high and I wondered if this reflected the experience of the operators who were residents on the orthodontic training program. It was important to look at the patient perceptions and this show that more patients reported difficulty speaking and eating use in the vacuum formed retainers and greater short-term comfort from the bonded retainers. This is a very nicely done small study where they used the good methodology and the findings were interesting. We need to be a little cautious because the sample size is based on a few arch alignment and it might not been sufficiently powered to detect differences in the other outcomes. Another important problem was the operators did not really analyzed data blind and this means that may again be some bias within the study. Nevertheless, I did think that the study provided lots of useful information and it reinforces my clinical impression that I would prefer to use VFRs which I won’t night only have this seems to work nicely for may has been reinforced by the randomized trials, “Bonded vs Vaccum Formed Retainers: A Randomized Controlled Trial. Part 1 : Stability, Retainer Survival, and Patient Satisfaction.”

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BRs Associated With Increased Plaque, Calculus Accumulation vs VFRs

Storey M, Forde K, et al.
Eur J Orthod 2017; epub ahead of print.

October 12, 2018
Dr. Mi-ri-nae Park

[초벌원고]

This is the second of the two papers that I am reviewing on retention, and this is concerned the effect the retainers upon gingival and periodontal health. The paper was published in the European Journal of Orthodontics, and it was called “Bonded Versus Vacuum-Formed Retainers: A Randomized Controlled Trial. Part 2: Periodontal Health Outcomes After 12 Months.”, and the lead author was Dr. Storey. They set at the test the null hypothesis that there was no significant difference in periodontal health between patients fitted with bonded retainers and vacuum-formed retainers over a 12-month period. This was a one to one parallel randomized controlled trial in which they enrolled, 30 patients who were randomly allocated treated with bonded retainers, and 30 who were fitted vacuum-formed retainers. The main outcomes in this study were periodontal measurements that were taken by calibrated operator. They recorded the amount of calculus using the Calculus Index, gingival health was measured by the Gingival Index as described by Lőe, and plaque accumulation was recorded using the Plaque Index. It was not possible to blind the patient or the clinician, to do group allocation in this study. They provided a large amount of data on this study, and I’m just going to really outline the major points. When I look the Plaque index, there was no real difference between the two groups. However, at 3 months, 6 months and 12 months, there was a significantly higher Plaque index for bonded retainers when compared to vacuum-formed retainers. When they looked to gingival health, they show that the gingival health was worse with bonded retainers after 3 months in the maxillary arch and after 6 months in the mandibular arch. When they looked to the Calculus Index, this increased from baseline in the mandible for both retainer types, and there was a general increase in median calculus scores for bonded retainers throughout the study. The overall conclusion was that the presence of bonded retainers appears to increase the levels of plague, gingival inflammation and calculus when compared to patients fitted with vacuum-formed retainers. However, after 12 months, the indices recorded do not suggest clinically significant implications for periodontal health. I thought that this was a good and interesting study that obtained data that was useful to us as clinicians. It was nicely done, a randomization and concealment were good, I thought that they wasn’t an issue of lack of blinding because this could lead to bias within the study. However, I thought it was important that this study was carried at in real world clinics and therefore it has degree of generalizability to our clinical practice. I was reassured that there did not seem to be a long-term harmful effects to the gingiva. However, I’m still concerned about long-term bonded retainer wear on my patients and my preferred retainer is still a vacuum-formed retainer. Bonded Verses Vacuum-Formed Retainers: Randomize Controlled Trial, Part 2 Periodontal Health Outcomes.

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Bone-Anchored RME Devices Increase Nasal Airflow, Decrease Nasal Resistance

Bazargani F, Magnuson A, Ludwig B
Eur J Orthod 2018;281-284.

Novomber 2, 2018
Dr. Hussein Aljawad

[초벌원고]

Rapid maxillary expansion is a common technique to expand the upper arch and to increase the size of the nasal airway. The original rapid maxillary expansion devices were tooth-borne, and this resulted in the force being applied to the maxilla by the teeth. However, a recent development has been the use of mini-implants that have been placed in the palate to anchor the RME. The forces, therefore, applied directly to the maxillary bones and this may increase the amount of maxillary expansion. The effect of this potentially increased expansion was looked at in this new trial which was published in the European Journal of Orthodontics. The study was called “The effects on nasal airflow and resistance using two different RME appliances: a randomized controlled trial” and the lead author was Dr. Bazargani. The aim of that trial was to asses and compare the influence of the conventional tooth-borne RME and the tooth-bone-borne RME on the nasal airflow and nasal resistance in growing children who had a constricted maxilla. A carried out randomized controlled trial in which they randomly allocated 40 patients who had unilateral or bilateral cross-bite with a constricted maxilla under in the early mixed dentition stage. Randomization and concealments were good, and they randomly allocated the patients to have treatment with a tooth-born RME device or a tooth-bone-borne expander in which there were two miniscrew implants which attached the expander to the palate. The expansion treatment lasted until the palatal cusps of the maxillary first molars contacted the buccal cusps of the mandibular first molars. As a result, there was overexpansion in both arches. Nasal airflow and nasal airway resistance were assessed for each nasal cavity by clinicians who are based at a nearby ENT department and data was collected at the start of the study and after the expansion period. The conclusion of the study, they found 4 of the tooth-borne and 6 of the tooth-bone-borne patients did not complete the study. This resulted in a number of drop outs being unequal and this means that there may be some bias in the study. However, the authors addressed this to a degree by imputing data for the dropouts. Their finding was clinically relevant, in brief, they found there were no difference between the groups in the start of the treatment, however after expansion, there was a higher nasal airflow in the mini-implant group and similarly there was a greater reduction in the nasal airway resistance for this group. Again, the differences were clinically significant. The overall conclusions were when it comes to treating patients with a constricted maxilla and upper airway obstruction, it might be wise to use a RME device that is anchored with mini-implants to the palate instead of the conventional design. I thought that this was an interesting study. It was carried out very well and reported clearly. They also dealt with the issue of dropouts using acceptable methods. I think that this study does add data on the effectiveness of RME on the nasal airway and it certainly appears that the use of bone-anchored RME is clinically effective. In general, this study should perhaps change our practice toward the use of mini-implant anchored RME devices. The effects on nasal airflow and resistance using two different RME appliances: a randomized controlled trial.

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Figure-of-8 Configuration vs Conventional Ligation

Little RA et al
J Orthod 2017;44:231-240.

November 9, 2018
Dr. Zheng Yuchen

[초벌원고]

Most operators realize the importance of the effect of friction upon the rate of tooth movement. And as a result, we all do our best to minimize the amount of friction between the brackets and the wire. This new study looked at the effect of friction upon the rate of tooth movement. It was published in the Journal of Orthodontics and the lead author was Dr. Little. The paper was called “The effect of conventional versus figure-of-8 module ligation on mandibular incisor alignment: a randomized controlled trial”. The authors pointed out that one of the most common methods of ligation that we use is elastomeric modules, and they have been found to produce high levels of friction. It has also been suggested that when the modules are tied in a figure-of-8 pattern, this produces significantly more friction than conventionally tied elastomeric or stainless steel linkages. As a result, the aims of this study, we're ready to determine whether using figure-of-8 modules affected the rate of lower incisor of alignment when compared to conventionally configured modules. They carried out a nice small study. And this was a prospective randomized controlled clinical trial with a four-arm parallel design with a 1:1:1:1 allocation ratio. The patients who enrolled in the study with those attending for fixed orthodontic appliances in a UK based orthodontic department. The main inclusion criteria was that they were 12 to 15 years of age at the start of treatment, they have to be in the permanent dentition with the mandibular incisor irregularity of between 5 and 10 mm. They obtained informed consent from the patients and the participants were randomly allocated to one of two groups. These were conventional module ligation or figure-of-8 module ligation, and the patients were stratified as to whether the treatment involved extractions or not in the lower arch. All the patients were bonded with the same type of bracket. Impressions were taken for study casts at the pre-treatment stage (T0), at 6 weeks (T1) and at 12 weeks (T2) after starting fixed appliance treatment. The chief investigator then evaluated the amount of crowding using Little's irregularity index at each of the stages of the study. The primary outcome measurement was the rate of lower incisor alignment, and this was specifically between three-time points. These were 0 to 6 weeks, 6 to 12 weeks, and 0 to 12 weeks. They carried out a sample size calculation and randomization sequence generation, and allocation concealment were all done adequately. They recruited 120 patients into the study, and they all completed the study. At baseline there were no real significant differences between the groups. When they analyzed the data, they showed that the rate of alignment was faster in the extraction group. When they looked at the effect of ligation, they showed that there was no statistically significant differences between the conventional module and the figure-of-8 module on the rate of alignment for all the three time periods. Their overall conclusion was the ligation with a figure-of-8 module has no clinically significant effect on the rate of low incisor alignment. I  thought that this was a nicely well done small trial that was carried out in a hospital setting. The question that I asked was also interesting because it does add to our knowledge about the effect of our wires and our brackets upon the rate of tooth movement. And I felt that it was very interesting that this was yet another study that showed that this had no effect. As a result, I feel that it does reinforce a lot of the trials that have been carried out on other bracket designs and types of wire and suggests that the operator has the greatest effect on the rate of tooth movement. All at all, I thought this was a very nice well done small study that helped that to our knowledge.

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Digital Wafers for Orthognathic Surgery Have Accuracy Similar to Conventional Wafers

Richard R.J. Cousely, et al.
Journal of Orthodontics 2017;44:256-267.

November 16, 2017
Dr. Suk-Cheol Lee

[초벌원고]

Conventional fabrication of orthognathic surgical wafers is a rather complex process requiring several steps that maybe prone to error. Recently a new developments in 3 dimensional technology have resulted in the ability for us to produce 3D printed wafers. The effectiveness this new technology was looked at in this paper that was published in the Journal of Orthodontics. It was called the “Accuracy of maxillary positioning using digital model planning and 3D printed wafers in bimaxillary orthognathic surgery” and the lead author was Dr. Cousely. This was a retrospective study and the investigators want to evaluate the outcome of Lefort I osteotomy movements in bimaxillary surgery where the presurgical planning process has involved standardized non-CBCT process combining digital model movements and 3D printed wafer fabrication. The study was done in the United Kingdom and was based on the record held at 1 major district hospital center with high orthognathic caseload, and the investigators searched for all bimaxillary osteotomy cases that operated on from January 2015 to 2016. They retrieved the planned surgical movements for each case from the hospital clinical record. They then compared these with the actual movements that were achieved per surgery. What they found was interesting. They managed to identify 30 consecutive cases that met their inclusion criteria. When they analyzed these cases, they showed that 13 out of the 30, 43% had at least a 2-mm discrepancy between the planned and actual movements in at least 1 of the cephalometric measures that they had evaluated. They found that this  was in around normal practice using conventional wafers. However, they pointed out that the method and use of fabrication of the 3D printed wafers, was considerably simpler than conventional wafers and therefore this technique had considerable advantages. I looked this paper closely because it has provided us with some useful clinical information. I do need to point out that this retrospective study and therefore could be subject to selection bias. However the authors did go to some a length to a straight on the cases that they have used had been consecutively treated and obtained from one department. As a result, I think there is useful information from this paper. And we could say that prospective cohort is needed to provide us with more precise information, it certainly appears that this technique may have considerable advantages over our conventional techniques.

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Hawthorne Effect Reported in Orthodontic Studies Is Suboptimal

Abdulraheem S, et al. 
European Journal of Orthodontics 2017;28:1-5.

November 30, 2018
Dr. Hun-kyung Park

[초벌원고]

One of the main advantages of reasons for carrying out a randomized controlled trials is to minimize the effects of bias. However, there are some biases that all trials are subject to and one of these is called hawthorne effect. This was evaluated for orthodontic studies in an interesting paper that was recently published in the European Journal of Orthodontics. It was called “Hawthorne effect reporting in orthodontic randomized controlled trials: Truth or Myth? Blessing or Curse?” and the lead author was Dr. Abdulraheem. The hawthorne effect is a common effect in clinical trials and it is defined as changes in the patient's or the therapist’s behavior when they are involved in the trial because they are to have increased knowledge or they know that their treatment is being observed closely. This is important in orthodontics because it may influence the cooperation rates of our patients. Therefore, the aim of this study was to investigate in 10 orthodontic journals how many trials considered the hawthorne effect and if it was considered to determine whether the hawthorne effect was related to just the patients or to the operators in the study. They carried out the systematic review in which the inclusion criteria with human randomized trials that use the individual as a unit, that is they were not split mouth studies. They carried out very precise search of the literature and attempted to identify all trials that has been published between the 1 August 2007 and 31 July 2017. At the end of research they identified 290 RCTs and they assessed these. They found that the hawthorne effect was considered or discussed in only 10 out of the 290 trials that they identified. That is 3.4%. In all 10 of these studies they reported that the hawthorne effect was related to a possible influence on the patient's behavioral change without including the effect of the operator. Their overall finding was there were very few orthodontic trials that consider the hawthorne effect. In the discussion they pointed out that when we are reading papers we should be very aware that the hawthorne effect exists and we should look quite closely to see if we could identify this particularly when unusual compliance rates or results recorded. We really need to be aware that the hawthorne effect may bias our study results but we do not really know its magnitude or its possible direction of effect. They also provided some useful information that showed from a recent systematic review that the main behavior that could perhaps be attributed to the hawthorne effect tend to disappear after 6 months trial period. When we consider the length of most orthodontic studies it may be that the hawthorne effect is evident in the first 6 months but in terms of a long-term follow-up the hawthorne effect may not have an influence on the overall conclusion of our studies. Overall, I thought that this was a very interesting academic paper that provided information that we should all bear in mind when we are reading a randomized controlled trial.

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Consider CBCT in Diagnosing Slanted Root Resorptionsl

Alamadi E, et al. 
Prog Orthod 2017;18:37.

December 17, 2018
Dr. Mi-ri-nae Park

[초벌원고]

Accurate diagnosis and assessment of the amount of any root resorption is very important in orthodontic treament plannning. This is also particulary relevant when we consider root resorption that may arise secondary to palatally displaced canines. This new paper was published in Progress in Orthodontics and was called “A comparative study of cone beam computed tomography and conventional radiography in diagnosing the extent of root resorptions” and the lead author was Dr. Alamadi. In their introduction, they pointed at that conventional two-dimensional techniques are the most commonly used methods for the diagnosis of most root resorptions. However, the distinct possibility that the use of CBCT image is a more reliable tool particulary for the detection of small resorption. There have been several studies that had invastigated accuracy of linear measurements in CBCT and these have shown that these are highly accurate. However, no study has really evaluated slanted root resorptions on periapical, panoramic, or CBCT view in relation to a true histological gold standard and this was the aim of their study. They looked up the patients who were enrolled in a prospective randomized trial on the interceptive treatment of palatally displaced canines by extracting the deciduous canines. All sets of the patients had a set of radiographic images before the extraction of deciduous canines, and these included, at least, two periapical, one panoramic view, and one CBCT. After the primary canines had been extracted, they re-examined histologically and also using linear measurements. The amount of histological root resorption was described with their gold standard. They found some interesting results. In brief, they showed that the panoramic radiographs tended to underestimate the amount of root resorption and there was a statistically significant difference between the root scores that is the amount of resorption for both panoramic and periapical images compared to the gold standard, while the CBCT values did not differ. This study assumedly showed that CBCT is the most accurate radiographic technique when measuring root length and root resorptions, particulary slanted root resorptions in deciduous maxillary canine. In their discussion, they pointed out that panoramic radiographs are not an accurate method to detect root resorption in the canine region and unfortunately periapical views did differ in assessing particulary slanted root resorptions. The overall conclusion was the CBCT is very useful in the detection of small root resorption particularly slanted root resorptions. I thought that this was a good and very carefully done study. It certainly adds weight the advantages of CBCT, however, the authors did point at that we do have to weigh up the additional radiation exposure versus the diagnostic gain. And I am sure that we will all consider this when we are reviewing all imaging requirements.

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Anesthetics Are Effective During Miniscrew Removal

Azeem M, et al. 
J World Fed Orthod 2017;6:160-164.

March 8, 2019
Dr. Mirinae Park

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Pain generated during orthodontic treatment is a common concern for both the patient and clinician. Miniscrews are an important contemporary treatment option that were utilized to provide enhanced orthodontic anchorage. Their insertion and removal are potential occasions for patent discomfort. The use of topical anesthesia and oral local anesthetic injections in the placement of miniscews has been discussed extensively in the literature. It is currently unclear, however, which pain control method is best utilized when the miniscrews are removed. In article published in the 2017 December issue of the Journal of the World Federation of Orthodontists addresses this issue. The paper was written by Muhammad Azeem and his colleagues from Pakistan and is titled ‘Comparison of the efficacy of anesthetics for removal of palatal and buccal miniscrews.’ The investigator’s objective was to assess the efficacy of topical and needle injected local anesthetics for the removal of buccal and palatal miniscrews. This was a randomized, double-blind prospective study with one group of 25 patients who had 2 palatal miniscrews in a similar anterior-posterior location at the opposite sides of the mid palatine suture. A second group of 30 subjects had at least buccal miniscrew in a similar vertical location in the interradicualr area between the maxillary second premolar and the maxillary first molar. The miniscrews were all from the same manufacturer and were of standardized size. They were placed and removed with the uniform protocol. All included miniscrews were stable during the course of treatment and at the time of removal. Prior to miniscrew removal the patients with palatal miniscrews received topical anesthesia randomly on one side and topical anesthesia followed by needle injection of local anesthetic on the other side. The topical anesthetic was 20% benzocaine gel and the needle injected anesthetic contained 2% lidocaine with epinephrine. The subjects with buccal miniscrews randomly received topical anesthesia on one side and a topical placebo gel on the other side prior to miniscrew removal. The removal of the screws was then performed by a different blinded clinician. If a patient felt the need for additional anesthesia at any time during screw removal, the needle injection of lidocaine anesthetic was given, and the procedure was classified as a failure. All subjects completed a visual analog pain scale at 4 different time points to quantify their experienced pain. They reported their discomfort levels before the anesthetic application, immediately after anesthesia, immediately after screw removal, and they reported a combined anesthesia and screw removal overall procedure score. Age, sex, anesthetic failures, and visual analog scale scores were recorded and analyzed statistically. Now, what did the researchers find? The anesthetic failure rate during palatal screw removal with topical anesthesia was 8%, compared to a 0% failure rate with needle anesthesia. The reported visual analog pain scale scores were significantly higher for the needle anesthesia at the anesthetic application time period. But the topical anesthesia, visual analog pain scores were higher during palatal screw removal and overall as compared to needle anesthesia. The placebo buccal group had an anesthetic failure rate of 26% during screw removal which was significantly greater in comparison to the 0% failure rate with the topical gel anesthesia. The visual analog pain scores were also significantly higher for placebo subjects during buccal screw removal and overall as compared to the topical anesthesia pain scores. There were no differences in the visual analog pain scores at baseline and for both groups, no significant correlations were found between age and sex verses the pain measurements at any time. The authors concluded that injected local anesthesia is more effective controlling perceived pain than topical anesthesia during palatal miniscrew removal. They also suggested that topical benzocaine gel is effective in controlling discomfort when removing maxillary buccal interradicular miniscrews. This study reported considerable individual variations and a wide range of pain tolerance in the subjects having miniscrews removed. Nearly 75% of the patients in the placebo buccal screw grouping and over 90% of the topical palatal screw group did not request additional anesthesia during screw removal. It would be interesting for larger, future trials to test the various miniscrew types and sizes for removal in other oral locations such as the mandible. If you`re interested in the complete article, it can be found in the 2017 December issue of the Journal of the World Federation of Orthodontists.

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Bite Force Is Correlated With Craniofacial Dimensions

de Lima Lucas B, de Souza Barbosa T, et al
J Orofac Orthop 2017;78:487-493

March 15, 2019
Dr. Hyun-Min Kim

[초벌원고]

Bite force has been previous identified as an indicator of the functional state of the masticatory system. The coordination of the nerve system, musculature, craniofacial bones, and the dentition plays an important role in generating bite force. What factors influence the maximum bite force obtainable in individuals? An article published in the November 2017 issue the Journal of Orofacial Orthopedics examines some of the factors that may have any impact on bite force. The paper was written by Barbara de Lima Lucas and her colleagues from Brazil and was titled “Influence of Anthropometry, TMD, and Sex on Molar Bite Force in Adolescents With and Without Orthodontic Needs” The authors’ objective was to assess whether the bite force is affected by the need for orthodontics, the presence of temporomandibular disorders (TMD), by body mass index (BMI), and by craniofacial dimensions. The study sample consisted of 80 complete dentition subjects with a mean age of 18 years. 61 of the participants were female and 19 were male. A digital dynamometer was used to measure each subject’s unilateral first molar maximum bite force. The maximum bite force was registered three times on both sides of the dental arch for each participant. Craniofacial measurements were performed directly with a bone caliper to calculate facial morphologic and cephalic indexes. Each subject’s BMI was measured and calculated. The presence and degree of malocclusion was assessed and an Index of Orthodontic Need was recorded. A standardized TMD evaluation was performed to assess any signs or symptoms of TMJ dysfunction. After the gathered data was analyzed statistically the investigators reported that bite force values were significantly higher for males than females. No differences in bite force was found between the right side and left side. The TMD incidents did not differ significantly between those with a normal occlusion and those with a malocclusion. Both TMD and BMI were not associated with maximum bite force. The greater the facial vertical dimension, the less the maximum bite force. And the greater the calculated facial index and the facial width, the greater the maximum bite force. The authors concluded that stronger maximum bite forces are found in males than in females and in subjects with smaller facial heights and wider facial widths. The maximum bite force appears to be negatively associated with the vertical dimension of the face. It was suggested by the authors of this paper as well as by others previously that the masticatory musculature is less biomechanically efficient in dolichocephalic subjects than in brachycephalic subjects thus the lower maximum bite force in dolichocephalic subjects. If interested, the complete paper is published in the Journal of Orofacial Orthopedics November 2017 issue.

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PEIR Is Related to Delayed Eruption

Alharbi F, Almuzian M, et al.
J Clin Pediatric Dent, 2017;41:374-380.

March 22, 2019
Dr. Insun Choi

[초벌원고]

Have you ever noticed a radiolucency in the crown of an unerupted tooth in one of your young patients? Pre-eruptive intracoronal resorption is a condition in which coronal radiolucencies are found in unerupted teeth. These lesions are typically detected incidentally with routine radiographs. This intracoronal resorption is usually located within the dentin adjacent to the dentino-enamel junction. These hidden resorptive lesions are often located in the central regions of the tooth crown, and may at times encroach on the pulp. The lesions are typically sterile well unerupted, but quickly colonize with oral flora on eruption, and generally become caries. In article published in the 2017 Journal of Clinical Pediatric Dentistry’s 5th issue, provides us with some information about this condition. The paper was titled “A Controlled Study of Pre-Eruptive Intracoronal Resorption and Dental Development”, and was written by Dr. Al-Tuwirqi and Seow. Their objective was to investigate the prevalence of pre-eruptive intracoronal resorption in populations of Australian and Saudi Arabian children and to assess the relationship of dental development with the incidence of intracoronal resorption. The study consisted of 842 Australian and 456 Saudi children between the ages of 5 and 14 years, who were screened for pre-eruptive intracoronal resorption. All unerupted teeth were assessed for intracoronal resorption by a trained calibrated examiner utilizing panoramic radiographs. The dental age of each subject was classified from the panoramic radiographs using the method of Demirjian and co-workers. This method involves determining developmental stages of seven permanent teeth on one side of the mandible, in order to obtain the subjects’ dental age. The patients’ calculated dental ages then compared to their chronologic age to determine if they have a delayed or an accelerated dental development. The presence of pre-eruptive intracoronal resorption and the calculated dental age were then correlated statistically. Now after analysis, what correlations did the researchers find? The prevalence of pre-eruptive intracoronal resorption in Australian children was 2% and the prevalence in Saudi children was 0.6%. This difference in prevalence was determined not to be statistically significant, however. No significant differences in intracoronal resorption prevalance was found between genders. The prevalence of pre-eruptive intracoronal resorption was highest in the mandibular 2nd molars and in the mandibular 1st and 2nd premolars. 31% of the teeth diagnosed with intracoronal resorption were classified as being impacted in comparison to 0.1% impaction incidence in teeth without intracoronal resorption. The intracoronal resorption subjects had a mean delay in dental development of 0.54 years compared with the subjects without intracoronal resorption, that were matched for age and gender. The authors concluded that dental development is significantly delayed in children with intracoronal resorption, and no significant differences in intracoronal resorption prevalence was found between Australian and Saudi populations. They suggested that ethnicity and gender are apparently not risk factors for intracoronal resorption. Intracoronal resorption prevalence has previously been reported to range from 2 to 6 percent in children, and to occur in 1 to 2 percent of their teeth. Currently, the etiology of intracoronal resorption is unclear, but the authors postulated that delayed tooth eruption may lead to inflammation and the entry of follicular resorptive cells into the dentin causing the pre-eruptive intracoronal resorption. If interested, the complete article was published in the 2017 Journal of Clinical Pediatric Dentistry’s 5th issue.

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Long-Term Use of TADs Show Mature Bone Surrounding Implants

Natarajan M, Bharath Rao K
J World Fed Orthod 2017;6:171-176.

March 29, 2019
Dr. Jin-An Jung

[초벌원고]

Temporary anchorage devices have make complex orthodontic tooth movement easier without the negative side effect of anchorage loss, but they are not full proved. Titanium is a biocompatible material but it is brittle and stainless steel while not brittle has biocompatibility issues. The goal of this study was to determine what happens on the surface of both titanium and stainless steel TADs in terms of surface corrosion, what metallic and other elements are detectable on the implants and what sort of bone is attached to the implants when they are removed. The authors obtained 16 temporary anchorage devices, half titanium and half stainless steel. Two types of each type were retained as control samples to be evaluated in an as-received condition. The remaining six TADs in each group were used in patients that required TADs for anchorage control during their treatment. The planned duration of TADs used was 12 months at which point the TADs were removed prepared for examination. The TADs were subject to visual examination under scanning electron microscopy and an elemental adsorption test was done with an electric current analyzer coupled to the scanning electron microscope. The TADs were inspected for visual corrosion in any bony material remaining on the removed TADs was tested histologically with H&E staining and visualized under optical microscopy. Under electron microscopy, the used TADs showed evidence of blunting at the tips and cratering of the surface along the threads. The as-received TADs showed no blunting or cratering. The stainless steel TADs showed more cratering 33% and the defects were noted in the region of the tip. In contrast, the titanium TADs show less cratering defects 26%, again they were concentrated in the tip. The neck and body of the TADs have less surface cratering. Surface elemental analysis showed that both types of TADs had elemental adsorption some related to oxide corrosion and some not. The researchers tested for the presence of oxygen, calcium, carbon and nitrogen. What they found was that calcium, carbon and nitrogen content of the used TADs significantly different from controlled TADs for the devices. The oxide layer of the titanium devices did not differ significantly for the control or study groups. Stainless steel TADs were different and it was noted that there was a reduction in the oxide layer and a reduced amount of carbon. When titanium was compared to stainless steel, there were significant differences in an oxide layers. There was more oxide in the titanium devices than in the stainless steel devices. Carbon adsorption was also higher in the titanium devices. There was some bone attached to the TADs when they were removed. This was also noted by an elevation in calcium. Histologic examination of the bone revealed that the bone was lamellar, meaning that it is taken at least 4 months to form and mature. This suggests that the TADs had achieved a secondary stability. The authors concluded from this finding that the longer the TADs remains in the mouth under physiologic an orthodontic loads, the more mature the bone becomes around the TADs. The finding of increased carbon uptake in the titanium implants was cause for concern on the part of the authors. Increased carbon concentration can result in some brittleness and taken in conjunction with the finding of increased cratering at and near the tip with an increase in lamellar bone. It could be inferred that these devices might be subject to fracture on removal.

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Effect of Interceptive Extraction of Deciduous Canine on PDC

Julia Naoumova, et al.
Eur J Orthod 2018;2:565-574.

April 5, 2019
Dr. Seong-Joon Ko

[초벌원고]

It is well-established clinical practice that when we detect a palatally displaced permanent canine tooth that we should consider the removal of the primary canine, as this will encourage a more normal eruption of the palatally displaced canine.  As a result, it is very important to identify any potential cut-off points for the successful outcome of this interceptive extraction by using a panoramic radiograph, as this is more extensively used in daily practice on a cone beam CT. And this was the aim of this study that was recently published in the European Journal of Orthodontics. The paper was called “The use of panoramic radiographs to decide when interceptive extraction is beneficial in children with palatally displaced canines based on a randomized clinical trial”, and the lead author was Julia Naoumova. The aim of their study was to evaluate the predictive power of panoramic radiographs to identify those palatally displaced canines that may erupt with or without the extraction of the primary canine. This was a subsection of results from a randomized trial that they had previously published. The participants in the study were children aged 10 to 13 years with maxillary unilateral or bilaterally impacted palatally displaced canines. The intervention was extraction of the primary canine and the control was non-extraction of the primary canine. And they simply observed to see whether the palatally displaced canines had erupted after a period of 12 months. They assessed the initial position of the unerupted canine on the panograph using the method described by Ericson and Kurol. This tended to be based on the alpha angle, which is the angle formed by the long axis of the canine and the midline and also the sector, which are the various sectors of displacement of the canine from the midline. They used logistic regression model to determine cut-off points for successful and unsuccessful outcomes. After they had analyzed the results they found that the extraction of the primary canine was the baseline variable that most affected the eruption of the palatally displaced canine. This was followed by the alpha angle, the sector measurement and the age of the patient. And overall they concluded that interceptive extraction is most likely to be of benefit when the alpha angle is 20-30° and the palatally displaced canine is located in sector 2 to 3. They suggested that simple observation that is non-extraction of the primary canine is likely to be successful for patients with palatally displaced canines with an alpha angle of less than 20° and the crown is in sector 2. However, when the alpha angle was more than 30° and the canine was very displaced in sector 4, it is likely that interceptive extraction will not be effective. As a result, a normal treatment for exposure of the palatally displaced canine should be carried out. I thought that this was a very useful and clinically relevant paper. It provided information on a very useful subsets of their data. One limitation that we do need to consider is that in their study they only included cases with good pre-treatment alignment. This really means that the findings of this study on this paper are only relevant to children with well-aligned arches. However, this criticism is very minor. And overall I think this paper provides us with great clinically useful information.

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Variation in Esthetic Performance of Esthetic Archwires

Collier S, et al
Orthod Craniofac Res 2018;21:27-32.

April 12, 2019
Dr. Dong-Wook Kim

[초벌원고]

With the advent of more esthetic fixed appliances, the use of white colored or esthetic archwires is increasing. Interestingly, there has been little objective or subjective esthetic evaluation of the appearance of these wires, after they have been used. And this was the aim of this new paper that appeared in orthodontics & craniofacial research. The paper was called “A Prospective Cohort Study Assessing the Appearance of Retrieved Aesthetic Orthodontic Archwires” and the lead author was Dr. Collier. The aim of the research was to evaluate the esthetic performance of three commercially available NiTi esthetic orthodontic wires. In order to do this, they carried out prospective cohort study of patients who were 18 years old in the permanent dentition and were due to undergo orthodontic treatment. Fifty of the participants were assigned to one of three 0.014-inch NiTi esthetic wires. These were the American Orthodontics Ever White™, the Forestadent Biocosmetic™ and the GAC High Aesthetic™. The wires were fitted and were then retrieved after they had been used for 6 weeks. They then used a Visual Analogue Scale to record their perception of the archwire esthetics both pre- and post-treatment. They also evaluated total coating loss using a special jig, an recording instrument. All fifty patients completed the study, most of the patients were female, and the mean age was 35 years. The average time that the wires were kept in place was 44 days. They showed that the American Orthodontics Ever White™ wires exhibited the greatest coating loss. This was followed by the Forestadent Biocosmetic™ and the GAC High Aesthetic™. The data analysis showed that the GAC and the Forestadent wire performed better than the American Orthodontics wire. When they measured the coating loss, again, they found that the American Orthodontics Ever White™ exhibited the highest level of coating loss followed by the Forestadent and the GAC wire. Again, the GAC and the Forestadent wires were statistically different from the American Orthodontics wire. The overall conclusions were that after intra-oral use, there is an increase in coating loss and it does lead to greater metal show, and this varies between the archwires. I thought that this was a clinically relevant prospective study as the appearance of wires in esthetic appliances must be important to our patients. I did spot that the patients were fitted with different makes and types of brackets, and the type of bracket may have influenced the performance of the wires. But the authors pointed out that the coating loss was not always related to the positions of the brackets, and they felt that this did not have an influence on the results. Finally, I thought that this was an very interesting clinically relevant study, and it certainly illustrates that we should have a better evaluation of the equipment that we use before they are released for general clinical use.

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Surgical Exposure of Palatally Impacted Maxillary Canines - Open vs Closed

Sampaziotis D, et al.
European Journal of Orthodontics 2018;40:11-22.

April 19, 2019
Dr. Hussein Aljawad

[초벌원고]

When we arrange for the exposure of a palatally displaced canine, we do not really know if there are any differences in the results of open or closed exposure of these teeth. This study attempted to answer the question. It was called “Open Versus Closed Surgical Exposure of Palatally Impacted Maxillary Canines: Comparison of the Different Treatment Outcomes - A Systematic Review” and it was published in the European Journal of Orthodontics and the lead author was Dr. Sampaziotis. The aim of the study was to systematically review the up-to-date literature in order to identify the most favorable technique for the exposure of palatally impacted maxillary canines. They carried out a fairly standard systematic review and they initially included randomized trials, quasi-randomized trials, and non-randomized trials. These are retrospective investigations, and this has implications for this review. They looked for papers that reported data on orthodontic patients of any age with a palatally impacted maxillary canine. They also felt that for the study to be included, it should include 2 groups of patients, one that was treated with an open exposure technique and another group that was treated with closed exposure. The outcomes were associated with periodontal health, esthetics, patient's inconvenience and orthodontic treatment complications. They carried out a standard electronic search. Data was extracted by two operators independently. They also evaluated the risk of bias with the ACROBAT tool and the Cochrane risk of bias tool. At the end of their searches, they found 9 articles, 6 of these are reported on randomized controlled trials and 3 of these were retrospective. They felt that the evidence was high for one of the randomized trials. For 2, there was moderate risk of bias and the retrospective studies were at serious risk of bias. They initially had intended to carry out a meta-analysis, but this could not be done because of the amount of heterogeneity between the studies. As a result, they carried out a very extensive narrative review because they could not do the meta-analysis, their overall conclusions were rather vague, and they really suggested that there was no real evidence in terms of periodontal outcome and esthetic appearance that arose from the 2 exposure techniques. And their overall conclusion was that more randomized trials should be carried out to provide us with more evidence. As a result, this was a systematic review that did not have an overall conclusion. There currently appears to be a trend in orthodontic publication for many of these systematic reviews to be published. Among their useful exercises, I am not sure that they add to our knowledge. I was also little concerned with this study because it included retrospective studies. This means that there is bias within the systematic review. We need to remember that the ideal systematic review should combine its evidence to data that is collected from randomized controlled trials. As a result of this review and the depth of high level evidence, it appears that the decision on the type of procedure can really be made on the clinical experience of the surgeon and the orthodontist and the opinion of the patient until we have more high level evidence on this rather difficult question.

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No Differences in the Effects of Tooth-Borne, Bone-Borne RME

Algharbi M, Bazargani F, et al.
Eur J Orthod 2018;40:90-106

May 10, 2019
Dr. Yuchen Zheng

[초벌원고]

RME or rapid maxillary expansion is a well-established orthodontic treatment technique. The main advantage of this form of expansion is that the heavy forces that have applied lead to separation of the mid-palatal suture, and this results in maximum skeletal change, and hopefully minimizing orthodontic tooth movement or tipping. Unfortunately, the heavy forces may produce mechanical stress on teeth leading to gingival recession, tipping and perhaps root resorption. In order to reduce the chances of this, new methods of RME application have been introduced in which the appliance can be fixed to various areas in the palate, and this was the subject of this interesting systematic review. It was published in the European Journal of Orthodontics, and it was called "Do different maxillary expansion appliances influence the outcomes of the treatment?", and the lead author was Dr. Algharbi. Their aim was to evaluate the immediate effects of different types of RME appliance design. In order to do this, they carried out a standard systematic review, and they attempted to find papers that were randomized clinical trials or prospective controlled studies, evaluating the different types of rapid maxillary expansion. The population of interest was patients who were aged eighteen years or less, and the outcome were the differences in skeletal and dental effects of these appliances. They carried out a standard electric search followed by a hand search were relevant, and the data collection was performed by three reviewers. At the end of their reviews, they found a total of seven articles. These were six randomized trials and one perspective non-randomized trial. It wasn't possible with them to carry out a meta-analysis because of heterogeneity within the data, and they therefore carried out a narrative review. Their main finding in conclusion was that all types of maxillary expansion appliance, that is bone or tooth anchored appliance produced significant expansion in the mid-palatal suture. However, they did not find any real difference in the dental effects of these appliances, and found it very difficult for further conclusions to be drawn. I thought that this was a good quality systematic review. They certainly confined the sources of their data to randomized trials and other high levels of evidence, and it is an unfortunate fact that due to differences between the studies in terms of methodology, the appliances tested and the outcomes that they could not carry out a meta-analysis. In effect, they concluded that all the appliances worked to a degree, and there are no real differences in tooth movement. I think that this represents our current state of knowledge, and I think we need to remember that conventional non-invasive treatment in which the RME appliance is fixed to the teeth, and there are very limited adverse effects. However, I will be very interested to see any trials that evaluate the effects of bone-borne rapid maxillary expansion appliances, because this certainly seems a logical step to take in the evolution of this very useful orthodontic appliance.

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Increased BMI May Be An Increased Risk Factor for Poor Removable Appliance Wear

Julia von Bremen, et al.
Eur J Orthod 2018;40:350-355

May 17, 2019
Dr. Hun-Kyung Park

[초벌원고]

 Over the last decade, there has been an increase in childhood obesity throughout the globe and this is a major public health problem. When we look at oral health, there is some evidence there may be an association between being overweight and an increased risk of caries and periodontal problems. There have recently been two papers in the orthodontic literature that show the overweight children didn’t coorperate as well during orthodontic treatment and they developed more white spot lesions than their normal-weight peers. However, these retrospective studies are may be subject to bias. The ideal type of study to answer this question is a cohort study and this was a new paper that was published in the European Journal of Orthodontics and called “Increased BMI in Children - An Indicator for Less Compliance During Orthodontic Treatment With Removable Appliances” and the author was Dr. Von Bremen. The aim of the study was to prospectively and objectively evaluate the compliance of orthodontic patients undergoing treatment with removable appliances and to compare the wear time of normal and overweight patients. This was a prospective cohort study and this was situated and done in two orthodontic practices. They enrolled from 2011 all patients who are undergoing treatment with upper expansion plates and Sander appliances. Each of these appliances was fitted with thermosensitive microsensors that evaluated and measured the amount the appliances were worn. They instructed all the patients to wear their appliances for 15 hours a day and they also recorded the body mass index of each of the patients. They eventually enrolled 50 patients. 25 of these were considered to be overweight and 25 were of normal weight. They found both normal and overweight children wore the upper expansion plate significantly more than the Sander Ⅱ appliance. When they analyzed the data, they showed there was an association between BMI and appliance wear, that is, the higher the body mass index the less the patients wore their appliances. Their overall conclusion was that within the limits of the study, they found the children who had an increased BMI had a higher risk of not cooperating as well during orthodontic treatment with removable appliances as their normal-weight peers and perhaps we need to provide more information to this group of patients. I thought this was a good study. It was interesting and it could provide us with useful information that allow us to target our advice to our patients. The good points were that it was a prospective cohort and all the patients were retained within the study. However, there was one problem which could be important and this was that the investigators did not measured social economic status of their patients. This is being shown in other studies that social economic status and obesity are related. Furthermore, social economic status may also be inversely related to compliance. Therefore, we must be very cautious in these findings in that there is a substantial confounder that is not taken into account within this paper. The authors draw attention to this in their excellent discussion. However, overall, I feel that this paper does provide information that may be clinically useful and we should perhaps consider this in our advice to our patients. Increased BMI in children - an indicator for less compliance during orthodontic treatment with removable appliances.

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Orthodontic Appliances May Produce Measurement Error in MRI Movies

Ozawa E, et al.
Prog Orthod 2018;19:7

May 31, 2019
Dr. Seong-Joon Ko

[초벌원고]

 Occasionally, I have been asked to remove orthodontic appliances for patients who are about to undergo MRI scans. This is because the radiologists have been very cautious about artifacts caused by the orthodontic appliances. This interesting question was evaluated in this new study that appeared in Progress in Orthodontics. The paper was called “Influence of orthodontic appliance-derived artifacts on 3-T MRI movies”, and the lead author was Dr. Ozawa. The aim of the study was to examine the influence of orthodontic appliance-derived artifacts on MRI movie images and to evaluate the effect on their diagnosis of speech problems. They recruited nine healthy males and seven healthy females with normal occlusion into this study. They then fabricated four types of customized maxillary and mandibular plates made of Biostar material. They then used these plates to contain the following orthodontic appliances. The first was a canine-to-canine retainer; the second was an 0.018-slot metal brackets for anterior and posterior teeth; the third was an 0.018-slot clear brackets; and the forth was no archwire being applied, this was the control. They then scanned the patients and analyzed their speech by evaluating oral-pharyngeal movement. They then viewed the videos and recorded the effect and the amount of distortion caused by the orthodontic appliances. They showed that the greatest amount of distortion was observed with fixed appliances, and the most severe artifact was associated with brackets on the molar teeth. However there were some inconsistency between their findings as the artifacts was still present on the other appliances. Their overall conclusions was that orthodontic appliances that included metallic materials may produce a significant error in the measurement of the articulatory organs when using MRI movie images. Importantly, metallic orthodontic appliances such as the fixed retainer and the metal brackets often made anatomical structures completely disappear and cause severe problems. This was an interesting paper, and certainly reinforced the findings of other studies. As a result it was clinically relevant and it showed that artifact problems may occur. Importantly, these were related to the position and the size of any of the wires and the brackets. The final conclusion was that we should remove fixed appliances when any of our patients are having MRI scans. However, we do need it to be guided by our clinical colleagues as this may not always be necessary. The Influence of Orthodontic Appliance-Derived Artifacts on 3-T MRI Movies.

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Continuous Archwire May Not Provide Desired Force to Intrude Maxillary Second Molar

Shintcovsk RL, et al
Am J Orthod Dentofacial Orthop 2018;153:396-404.

June 7, 2019
Dr. Dong-Wook Kim

[초벌원고]

 Continuous arch and rectangular loops for the correction of consistent and inconsistent load systems in extruded and tipped maxillary second molars

As in another article review this month, the application of force to operate a molar tooth in needs to be within a safe range of force to protect the tooth in the periodontion, but also needs to be sufficiently strong and directed to cause the desire to smoothened. In this paper, the authors are looking at examples of supraerupted and tipped maxillary second molar teeth and how forces apply to this teeth for uprighting and intrusion can be made effective. The author is making an important point. Four systems can be either consistent or inconsistent and this largely depends on how the forces are applied. The authors state that a load system is inconsistent when the direction of applied force is incompatible with the direction of force required for tooth movement. In certain circumstances, an inconsistent load is produced by continuous arch mechanics and in order to successfully intrude an operated tooth, a consistent load system is needed and this is usually done by the in cooperation of the loops into the wire. In a scenario posed by the study, the authors state that supraerupted and tipped maxillary second molars can be subjected to consistent or inconsistent load systems depending on how the teeth are tipped. Mesial or distal crown tip result in different load systems and require different approaches for intrusion and uprighting. They state that when the crowns are tipped mesially, continuous wire mechanics are inconsistent and loops are usually required. The offset is true when the crowns are tipped distally. To compare the different crown tip scenarios, the authors used a maxillary typodont mounted to a load sensing system. 0.018 X 0.025 brackets were placed on the first and second molars at a distance of 7mm between them. To simulate extrusion, the molar tube on the second molar was bonded 2.5mm to the occlusal of the first molar bracket. The load system allow the second molar to be tipped either mesially or distally by 20 degrees. To apply force to the system, the authors bent 10 wires out of 17 X 25 TMA wire into a box-shaped loop. For continuous arch loads, the authors use sections of 0.014 super elastic nickel-titanium wire. The wire segments were tested in both 20 degrees of mesial and 20 degrees of distal tip for total of 30 archwire segment tests. The nickel-titanium continuous wire segments were used both mesial and distal angulation configurations. The forces placed on the second molar were recorded in N/mm. What they found was that for the inconsistent tests, second molar tipped crown mesially. The forces produced by continuous and loop configurations were different. The second molar, the loops produced 2.11N/mm, while the continuous wires produced a mean of 0.15N/mm. The reciprocal forces on the first molar were similar with the loop system producing significantly higher forces than the continuous segment. These forces would cause an extrusion of the second molar with no tip correction. Therefore, the continuous wire is an inconsistent load system in this instance that would not correct the extrusion or angulation of the second molar. These values were reversed when the consistent load systems were tested with the second molar tipped distally. In the second molar, the force value recorded for the loop system was –3.06N/mm, while the continuous wire segment produced –4.25N/mm. Force values at the first molar were similarly reversed with higher forces produced by the continuous wires. Contrary to the first test, the loop system does not produce a favorable intrusion in tip correction and therefore the continuous wire segment in this case is the consistent load system. Consistent load systems tended to produce greater vertical movements in all cases with a mesial or distal tip was seen. But the authors note that there were really only two variables that were in the direct control of the operator. The inter-bracket distance and the modulus of elasticity of the materials being used. The inter-bracket distance could probably be changed somewhat. But the only way to change the modulus of elasticity would be to change the wire material. One important aspect that was noted was that vertical changes were noted in the anchor teeth. Additional anchorage control the reciprocal vertical forces is necessary to avoid unwanted tooth movement in the first molar. The conclusion to the study is that whether the maxillary second molar is extruded and tipped mesially or distally, the load system used to correct this extrusion and tip must be consistent. For mesial tip, that means a loop wire system. For distal tip, a continuous wire system is sufficient.

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Stress Distributions in Different Molar Uprighting Techniques

Abrão AF et al.
Am J Orthod Dentofacial Orthop 2018;153:415-421.

June 14, 2019
Dr. Mirinae Park

[초벌원고]

Photoelastic analysis of stress distribution in mandibular second molar roots caused by several uprighting mechanics. In this study, the authors want to examine the stresses in various types of loads put on the roots and bone, and the teeth. In the clinical scenario they pause the common problem of mesially angulated mandibular second molars where there is no first molar present. The rationale for uprigting teeth in this situation is clear, whether this to prevent periodontal defects or redirect occlusal force along the long axis of the tooth whether to upright and protract the second molar or whether to provide adequate space for the mandibular molar implants is are common of problems of orthodontic practice that we should understand the uprighting mechanics. The authors highlights several mechanical ways to upright an mesially tipped molar various types of loops, such as box and T-loops, helical springs, tip-back bends, open coil springs and temporary anchorage devices. It might be possible to calculate the various forces and moments that are produced by all these methods, but this authors choose this technique to visualize where the stresses are concentrated in four of these different mechanisms ; Miniscrew anchorage, cantilevers, T-loops and the open coil springs. To do this, the authors conducted in vitro study the artificial teeth were embeded into the flexible epoxy resin. This resin was observed with the polaroscope instrument that highlighted areas of stress within the resin. This method of stress observation is part of the standard testing for the American Society for Testing and Materials. What is observed when stress applied what are called optical fringes, these fringes appear at high stress areas as more stress is applied the shape and distribution of the optical fringes  changes to reflect higher or lower concentrations of stress. The quantity and quality of the stress is seen an various color transformations in the polaroscope ranging from 0 to greater than 3. The distance between any two or more fringes  also give indication of the amount of stress present, small distances between fringes are indicative of higher stress concentrations. There are total of 4 test scenarios, to test the miniscrew stresses, the miniscrew is inserted into the typodont in the retromolar area and uprighting was accomplished to the elastomeric chain between the screw and the button on the mesial surface of the second molar. In the case of the T-loop and the cantilever, the typodont teeth were bonded with the 022x028 bracket system, and the loop and cantilever were formed in 019x025 beta titanium arch wire. For the open coil spring test, the wire used was 018 stainless steel wire the coil spring placed on to the wire segment between the second premolar and second molar. The forces were measured at  50, 100, 150, 200, 250, and 300 grams. Stress distributions were noted at each of the test scenarios, and the miniscrew sample, the authors noted that stress was concentrated around miniscrew and in the second molar in the cervical area of the distal root. They found that the stress was evident at 200g and above, where the stress also noted in the mesial root. In the cantilever spring test, the authors observed stress fringes starting from 100g in the area of the missing molar tooth. Above 100g, the stresses were observed in both teeth on either side of edentulous area. In second molar, the stresses were concentrated in the cervical region of the mesial root and the apical region of the distal root. The T-loop springs showed the stress is arising at 150g force primarily in the area of the apex of the mesial root. The open coil showed the stress forming at the 50g level and increased as the load was increased. Stresses were observed in both the cervical and apical zones of the second molars. In this study, the authors found that the stresses  created by different uprighting techniques differed, they found that the lowest stresses were created by the miniscrew set-up whether the greatest mean stresses were created by the cantilever set-up. This was despite the fact, the open coil spring has the stress as noted for relatively light force 15g. They concluded from the quantitative results that the miniscrew uprighting technique was the most favorable and that it would be likely to produce lower overall stresses on the second molar where possibly minimizing the side effects of extrusion and the root resorption. They further conclude that as long as the force level was kept to 150g or lower, the each of these uprighting techniques were biologically acceptable.

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Cervical Vertebral Maturation Method -- A User’s Guide

 McNamara JA Jr, Franchi L.
 Angle Orthod 2018;88:133-143.

September 6, 2019
Dr. Mirinae Park

[초벌원고]

A patient's stage of craniofacial skeletal maturity often impacts the treatment plan and timing of their orthodontics. There are several methods available to assess a growing individual's level of craniofacial skeletal maturity including chronological age, statural height change, hand and wrist maturation, and cervical vertebral morphology. The cervical vertebral maturation method, CVM, was introduced decades ago, and its utilization as a means of assessing craniofacial maturity has increased in recent years. There is, however, a continuing controversy in the current literature about the accuracy and reliability of this technique to classify the status of subjects craniofacial maturity. And article published in March 2018 issue of the Angle orthodontst, focuses on the utilization of the CVM technique. The paper was written by James McNamara and Lorenzo Franchi and was titled 'The cervical vertebral maturation method: A user's guide'. The author’s objective was to provide user-friendly guidelines that describe the CVM classification method to facilitate the use of CVM in clinical practice and to enhance inter- and intraobserver reliability. This article provided a detailed descriptive narrative of the CVM technique that describe the use of lateral cephalograms to identify the six stages of CVM based on the morphology of the second, third, and fourth cervical vertebrae. The narrative describes the process of using the CVM method to classify the craniofacial skeletal maturational stage of an individual at each time point during the craniofacial growth process. Diagrams and the notable examples of 2 dimensional lateral cephalogram radiographic images that were representative of the CVM stage classifications were also contained in the paper. They suggested that the CVM classification protocol with the 1st step to determine whether the inferior border of the C2, C3, and C4 is flat or concave. The 2nd step is to evaluate the morphologic shape of C3, and C4 as these vertebrae typically change shape progressively from trapezoidal to rectangular horizontal, to square, to rectangular vertical as subjects mature. They suggested that subjests with cal stages CS1 and CS2 are prepubertal, and those with stages CS3 and CS4 are circumpubertal, and those classified CS5 and CS6 are postpubertal. The authors acknowledge the criticism of the accuracy and reliability of the CVM method in the literature. They suggest that this paper's description of the technique may be an aid in enhancing the reliability of the CVM technique and that a clinicians experience with the technique may be helpful in facilitate the use of the CVM method in everyday practice. Some studies have indicated that the CVM method of categorizing craniofacial growth is no more accurate than the wrist radiographs or the patient's chronologic age. The authors suggest that the CVM method of staging may be used as an adjunct technique with the other maturational indicators in the treatment planning process. This paper provides us with a concise descriptive guideline for those interested in utilizing the CVM technique. If you wish to read the complete article, it is found in the March 2018 issue of the Angle orthodontists.

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Online Presence of Orthodontic Journals Needs to Improve

Livas C, Delli K
Eur J Orthod 2018;40;193-199

September 20, 2019
Dr. Hyunmin Kim

[초벌원고]

This is a non-clinical paper but I thought it was interesting because it really looked at the visibility of orthodontic research articles on the Internet. The paper was called "Looking Beyond Traditional Metrics in Orthodontics: An Altmetric Study on the Most Discussed Articles on the Web".  The lead author was Dr.Livas and it was published in the European Journal of Orthodontics. In their introduction the authors outlined that one of the most common ways of measuring the effect or the impact of a journal article is to look at the number of citations. However, while this was sufficient for papers that were published before the development of the Internet and social media, it’s clearly now is not the case. And when we look at the impact of a paper, we should look at many other factors. For example, the number of times of a paper was blogged about or mentioned or even the number of times that a paper is mentioned on Twitter. The most common new method of measuring the impact of publications is called altmetrics. And we do not know much about the effect of altmetrics or the measurements on altmetrics on orthodontic papers. As a result, the aim of their study is to identify top altmetric orthodontic articles of all time and to investigate altmetric scores in relation to the publication details and citation counts. They carried out the study by evaluating the altmetric search engine on data from papers that were published up till April 27th. They targeted papers that were published in the 11 main orthodontic journals. Through each of the papers they collected data on the article title or the journal title, the time since publication, the affiliation of the author, the origin of the paper and then the number of times of the paper was either blogged, cited, or mentioned on Twitter. When they looked at these 200 articles they found that 73 had been published in the American Journal of Orthodontics, 60 were published on the European Journal of Orthodontics and 39 were published in the Angle Orthodontist. The other papers were published on a wide variety of other orthodontic journals. They found that the most popular subjects were the evaluation of treatment outcome using oral health quality of life(OHRQOL). And the studies that investigated socio-demographics had a significantly higher altmetric score than diagnostic studies and these were studies that use cephalometric measurement as their main outcome. The most important finding was the altmetric score was not really related to number of former citations made in other orthodontic journals. They also showed that in their top three articles there were two studies that reported of the use of AcceleDent. These were positive studies in that they showed that there was an effect of this appliance on tooth movement and pain. They were therefore highly publicized and quoted on the Internet. However, another study showed there was no effect of treatment did not have such high altmetric score and these shows the effect of advertizing and general circulation of positive clinical trials. I thought that this was an interesting paper and it is not just relevant to academics because it certainly illustrated very nicely the effect of the Internet and the use of advertizing in the publication of orthodontic studies. It did show that all altmetics have the potential to measure the social impact of articles published in our journals and it certainly should be combined with other metrics that I used to measure the impact or the effect of an article upon our clinical practice.  

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Lont-Term Outcome of Herbst Treatment Shows Good Stability

Bock NC, Saffar M, et al.
Eur J Orthod 2017;(July 11)

September 27, 2019
Dr. Insun Choi

[초벌원고]

Fixed functional appliances are widely used for the correction of Class II malocclusion. However, there is only little evidence regarding the long-term treatment change and the outcome of treatment, and this was looked up in this very interesting study that was published in the European Journal of Orthodontics. The paper was called "Long-term post-treatment changes and outcome quality after Class II:1 treatment in comparison to untreated Class I controls", and the lead author was Dr. Bock. That they wanted in this study to evaluate the long-term post-treatment occlusal stability and outcome quality after Class II division 1 treatment provided with the Herbst and multibracket combination. They took 119 patients with the mean age of 13 years from the records of their clinic. Each of these patients had a severe Class II division 1 malocclusion before treatment with an overjet of a mean of 8.2 mm. Treatment was carried out using a Herbst appliance as well as different types of labial straight wire multibracket appliances. They attempted to obtain data on these patients on after a lengthy process of recruitment, 52 patients finally accepted and took part in theirs study, the average age of the patients was 33 years. So this was a substantial amount of time after that treatment was completed. For each of the patients, they obtained consent and then took impressions of upper and lower arch. They then recorded sagittal molar and canine relationships, the overjet, the overbite, and the PAR index. They then compared these data from these group of patients with the control group. They said that these were normal control group, so these were patients who were Class I with no orthodontic treatment, and they were collected from a longitudinal growth study of children in Finland. In this study, the patients were followed from age of 7 until 33 years of age. As a result, they quite closely matched the group of patients who had had Herbst appliance treatment. They managed to get 52 of the patients to attend for their record collection. On at this visit, they found that the mean PAR scores were 8.2 for the treatment group, and for the control group, the mean PAR scores were 8.9. These were not statistically significant. They concluded that the occlusal outcome of the Herbst-multibracket treatment was good after lengthy period of time. I thought that this study was very ambitious, and the authors did remarkably well to get such a large sum pool of patients to return. While we have to consider the effect of selection bias, in that they may well be differences between the patients who volunteer to attend and those who could not attend. we also need to consider that the untreated control group may be influenced by secular trends, and this is being shown for other data that obtained from growth studies. Nevertheless, I cannot help feeling that these authors have possibly done the best that we can get from this type of study, and their findings do provide us with very useful information on the overall very good stability of Herbst-multibracket treatment.

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Secondary hyperparathyroidism causing increased jaw bone density and mandibular pain: a case report

Thomas Aerden, et al.
RAL MEDICINE Vol. 125 No. 3 March 2018

October 11, 2019
Dr. Jinan Jung

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Secondary hyperparathyroidism causing increased jaw bone density and mandibular pain: a case report

Systemic diseases which have an impact on bone metabolism are an important consideration for orthodontists. Adult patients sometimes present with problems that are indistinct and confusing but which can have a negative impact on orthodontic tooth movement. We only need to think of patients were taking bisphosphonates to know that this is true. In the case of hyperparathyroidism, the situation is similar. parathyroid hormone is an important to control mediator for bone metabolism. In their case report, the authors provided very comprehensive review of the role of parathyroid hormone. they state that this hormone controls serum calcium levels by acting on the kidneys to take up calcium and cause release of calcium from bone. Therefore the typical bony picture of a patient with elevated parathyroid hormone is bone with loss of lamina dura and trabeculation. These effects are not limited to any one bone and a jaws can show the effects of elevated parathyroid hormone. They also state that there are 3 types of hyperparathyroidism conveniently called primary, secondary and tertiary. Primary hyperparathyroidism is often caused by tumors in the most common treatment is removal of the parathyroid gland. Secondary hyperparathyroidism can be treated pharmacologically but surgical removal of the glans is still a treatment option. The same options are available for tertiary hyperparathyroidism of the authors state that drug therapy in the tertiary form of the disease are not always effective. Some of the oral manifestations of hyperparathyroidism are loss of the lamina dura decreased cortical bone thickness or destruction of the cortical bone, tooth displacement, root resorption, obliteration of the mandibular canal, and dystrophic calcifications. Obviously these findings have some implications for orthodontist in particular but Dental Professionals in general. In the British medical journal best practices website, It is reported that the incidence of primary hyperparathyroidism an individual's over 40 years of age is 1 in 500 females and 1 in 2000 male making this a fairly common disease. The increase in adults seeking orthodontic treatment combined with the relative commonality of the disease makes it likely that orthodontists. We'll see some patients with this condition during their practice lifetimes. So some awareness of the problem is important. in this case report the authors state that the average age of patients with hyperparathyroidism is roughly 34 years, but that patients with secondary hyperparathyroidism can present with the disease at earlier ages. This particular case report is the presentation of an unusual manifestation of hyperparathyroidism. In this case, the author report that a 32-year-old male patient reported with symptoms of pain in the symphysis and submandibular regions of the mandible. The patient experience sudden onset pain that would last several hours to several days then disappear for several weeks after which the pain pattern would repeat itself. It reported to them that this has been occurring for 3.5 years. He was managing the pain with oral ibuprofen medication. On their examination, the authors noted at some enlarged lymph nodes in the submandibular region. They obtained panoramic radiograph and noted a thickening of the mandibular cortical bone in the symphysis area between the mental foramen are as well as some thickening of the bone in the anterior maxilla, which the patient record is asymptomatic. They perform to 99mTc uptake analysis and found it bone was being deposited at an elevated rate in the anterior mandible. A biopsy of this bone revealed that it was bone with increased density, but showed no other pathology. They had the patient undergo a blood assay and found that there was elevated parathyroid hormone and a decreased level of serum vitamin D. There was a decrease in serum calcium level renal and liver functions were normal and the serum phosphate level was also normal. Based on the findings in the blood work the patient was given a vitamin D supplement regimen and 6 months after completing this treatment the patient reported no further pain. The author stress that this case report is of an unusual presentation of secondary hyperparathyroidism. More typical presentation showing increased level of parathyroid hormone and decreased levels are both calcium and phosphate. A finding of elevated alkaline phosphatase is indicative of high bone turnover. They also stated that the relationship of hyperparathyroidism and kidney disease is important and these can have other effects in the mouth including neuropathy, postextraction complications, periodontitis, and tooth mobility.  Orofacial pain of Unknown Origin in adult patients should be taken seriously and might warrant a discussion with the patient's physician to help rule out any metabolic abnormality. We should also be aware of what radiographic signs to look for including the atypical signs and direct the patient to appropriate treatment.

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Prediction of Changes due to Mandibular Autorotation Following Miniplate-Anchored Intrusion of Maxillary Posterior Teeth in Open Bite Cases

Kassem HE, Marzouk ES
Prog Orthod. 2018;19:13.

October 18, 2019
Dr. Hussein Aljawad

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Over many years, there have been several attempts to predict the results of orthodontic treatment mechanics. This new paper looked at ways of developing statistical models that attempted to predict the changes of mandibular autorotation following intrusion of the posterior buccal segment. The paper was published in progress in orthodontics and it was called “Prediction of changes due to mandibular autorotation following miniplate-anchored intrusion of maxillary posterior teeth in open bite cases” and the lead author was Dr. Kassem. The objective of that paper was to present regression models that could help provide more accurate prediction of the effect of molar intrusion on several skeletal, dental and soft tissue parameters which maybe important for the clinician. They recruited a cohort sample of 28 young adults who had anterior openbite and posterior vertical maxillary dental alveolar excess. They provided treatment to their patients using this protocol. Firstly, the maxillary posterior segments were leveled with sectional wires going from the 1st premolar to the 2nd permanent molar when they reached 0.019 X 0.025 SS, they then fitted a double transpalatal arch. They then fitted zygomatic anchored miniplates under local anesthetic and used a NiTi coil spring to provide a force of 480 grams to each side. They took cephalometric radiographs before and after maxillary intrusion. They then constructed statistical models which aimed to predict the amount of tooth and bony movement anteriorly in terms of autorotation that were related to different level of maxillary molar intrusion. They presented a large amount of data, but I felt the most important data was that the hard tissue chin point moved forward 79% of the distance that the maxillary 1st molar was intruded. Unimportantly, the overbite increased by twice the intrusion of the maxillary segments. I thought this is a very interesting paper and provided us with a large amount of useful information. It certainly helped fill the void in our knowledge about the effect of intrusion mechanics with temporary anchorage devices. We do need be little cautious because this was retrospective data and the effects of treatment maybe overestimated. Nevertheless, this provide a good pointer about the treatment effects we may see when intruding posterior segments using temporary anchorage devices.

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OIRR Mesured by CBCT Imaging Is Minimal

Aikaterini S et al
Eur J Orthod 2019;41;67-79

October 25, 2019
Dr. Dongwook Kim

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We all know that orthodontic root resorption is common side effect of orthodontic treatment, and this was a new systematic review which gave us newer information on this problem. The paper was published in the European Journal of Orthodontics, and it was called “The evaluation of orthodontically induced external root resorption following orthodontic treatment using cone beam computed tomography(CBCT): a systematic review and meta-analysis, and the lead author was Dr. Samandara. We all are very familiar with orthodontically induced root resorption, and there has been many studies that have attempted to evaluate the possible causes. These studies have provided us with useful information, however, most of them have used two-dimensional radiographs. And recently, the adventive CBCT image has allowed us to measure root resorption more accurately. As a result, the authors did this new study to answer this question. That is, what is the main amount of orthodontic root resorption measured with CBCT imaging? They did a sand of systematic review of the literature, the peacock was the participants were orthodontic patients in the permanent dentition, the intervention was any type of orthodontic treatment, and the outcome was the amount of root resorption measured by CBCT imaging. They used one establish systematic review methodology, on covered electronic databases, precise data collection, and assessment of risk of bias of studies. They did include all CTs and retrospective non-randomized studies. At the end of our searches, they identified thirty applications, only six of these with trials, six with prospective non-randomized studies, and eighteen with retrospective studies. They provided data on 1219 patients, age between 11 and 26 years. They felt that four of the randomized trials with high risk of bias, or the non-randomized studies and retrospective studies were also at high risk of bias. They presented a large amount of data in the text and detail tables. I think the main important findings were that when fixed appliances were used, the mean root resorption was 0.8mm, but RME was used, this was 0.4mm. When they measured the resorption for individual blocks of teeth, they showed that anteriorly, the root resorption was 0.9mm and for posterior teeth, it was less at 0.2mm. These results were interesting and clinically relevant. However, when I looked closely at the review, we do need to be careful about how we interpret findings. This is because that included retrospective studies within the review. And interestingly, they classified all the studies as being high risk of bias. Unfortunately, this simply results in a review in its biased. And it is fortune for us to consider that if systematic review is going to be a value that it should only include trials. They did sensitivity analysis that did show that the retrospective studies tended to show greater root resorption than the prospective studies. As a result, I do further we can conclude again with some caution that when CBCT is used to measure root resorption, the average amount of root resorption is between 0.6 and 0.8mm. This is small amount and it is very surely.

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Discrete Elements of the Mandible are Implicated in Skeletal Asymmetry

You KH et al
Am J Orthod Dentofacial Ortho; 2018;153;685-691.

November 08, 2019
Dr. Hussein Aljawad

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Three-dimensional computed tomography analysis of mandibular morphology and patients with facial asymmetry and mandibular retrognathism. Evaluation of mandibular asymmetry doesn’t always localize the asymmetry to one part of the mandible or another. A common area of interest is in the condyle where a mandibular growth occurs but changes also do occur elsewhere in the mandible. The authors of this study hypothesize that the mandible might be composed of different skeletal units that could be evaluated independently and then correlations and changes between these units could be derived make a better understanding of where the differences exist between right and left sides. The authors divided mandible into several parts, condylar process, coronoid process, angular process, alveolar process, body and chin. From these they made linear and angular measures to establish if possible, which mandibular units are responsible for asymmetry. They also used a midline plane to determine differences in mandibular volume between right and left sides. 50 cone-beam computed tomography images were collected for this study. To be included, the subjects had to be at least 19 years old, have an ANB angle of 4 degrees or greater, mandibular plane angle either greater than 32 degrees or less than 40 degrees, no history of trauma or joint disease and no systemic diseases. For horizontal reference, the authors used Frankfort plane and then constructed a mid-sagittal plane perpendicular to Frankfort and through Nasion. Landmark placement was performed in all 3 axis on the CBCT images. For volume assessment, the mandible was divided in half, left and right and each half was further divided into ramus and body volumes. The authors divided the total sample into 2 groups depending on the deviation of Menton from the vertical reference plane. Group one called the symmetry group, had deviations of Menton less than 2 mm and the second called the asymmetry group had deviations of Menton more than 4 mm from the vertical reference plane. Both groups were equally divided between male and female subjects. The results of the study showed that for group one, the symmetry group, there were essentially no left right differences. For the asymmetry group, there were significant right left differences noted. The deviated side, meaning the side to which Menton was deviated showed significantly smaller condylar, coronoid and body measurements. And the condyles on the deviated side were found to be narrower than on the non-deviated sides. The authors reported that the condylar unit were significantly shorter on the deviated side. Volumetrically, both the ramus and body volume were to be found smaller on the deviated sides. Additionally, Menton deviation was positively correlated with mandibular ramus volume and condylar unit length. There seem to be two main areas of the mandible that are implicated in the location of the asymmetry, the condylar unit and the body units which the authors found were both shorter on the deviated side. however the deviation was not correlated with body unit length only with the condylar unit length. The implication is that the deviation of Menton from the midline reference could indicate that condylar unit length on the shorter side is the source of the asymmetry. Another interesting finding was that the coronoid unit length on the deviated side was shorter than on the non-deviated side. One theory that they proposed to explain this is that because the coronoid process is the attachment point for temporalis muscle. The difference in coronoid units size could be related to left right differences in the temporalis muscle volume and therefore muscle activity. However, a study that they cite from Suzuki et al. in 2017 found that even in cases of hemifacial microsomia, the volume of temporalis muscle does not differ between left and right sides. In this current study, the coronoid length was not correlated with Menton deviation despite the difference in size compared to the non-deviated sides. They further theorized that muscular activity might be different and this might account for the size difference noted but that would require additional research. Overall, 3 of the skeletal units of the mandible the condylar, the coronoid and body units were found to be implicated in the mandibular asymmetry unit.

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Dental Plus Skeletal Age More Reliable Indicator of Growth

Machado MA et al
Arch Oral Biol; 2018;85(January):166-171

November 15, 2019
Dr. Zheng Yuchen

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 Effectiveness of three age estimation methods based on dental and skeletal development in a sample of young Brazilians. The estimation of a patient's age is an important problem for orthodontists, as often skeletal and dental age do not correlate well with chronological age. In the introduction to this study, the authors discussed the need for accurate age determination for other reasons, including an incidence of violence or immigration, or forensic age determination in the case of disasters. They cite some studies that have shown that dental and skeletal development occur in parallel at some points in time. And that these methods can be used to accurately determine the age of a subject. They state that combinations of methods are generally better than a method that relies on only one parameter. The aim of this study is to test three validated age estimation methods on a sample of brazilian children. These methods had not been used in this population before. This was a retrospective study of 126 female and 108 male subjects using panoramic and hand-wrist radiographs. A total of 468 radiographs were evaluated. The average chronological age of the subjects was 11.27 years. But to be included, all of the subjects had to be less than 14 years old at the time of the radiographs. The subjects were divided into five groups based on chronological age. To perform the analysis, the authors used the method originally proposed by Cameriere et al.in 2006. This analysis examines the teeth from central incisor to second molar, excluding deciduous teeth. Hand bones and radius and ulna also analyzed. The tooth on hand-wrist data were fed into a formula that calculated the likely chronological age from the data. After the data were collected and analyzed, the authors found that dental evaluation alone and dental evaluation combined with skeletal analysis, both found age estimates that were not statistically different from the true chronologically age. However, age estimation that relied on skeletal data only were less accurate, with greater errors evident across a wide range of the measurements. Dental age estimates were generally very accurate, except for the oldest of the five age subgroups. And the combination of skeletal dental measurements, there were statistically significant differences between chronological estimated age for a number of subgroups, the youngest age subgroup had very good agreement between chronological estimated age. A sex difference was found with dental age. Estimation is being better in females than in males. An interesting finding in this study was that dental development was a better age predictor than skeletal development. One of the possible reasons for this finding was that the sample population of Brazilian children was different than the population that the age estimation formula was based on, which was a sample of Italian children. The authors suggest that environmental factors affecting skeletal development that are different between these two populations might explain some of the differences. But it also suggests that growth estimation formulae might need to be derived differently for different populations. Another interesting finding was that as patients age, it becomes harder to accurately estimate their age. The authors state that this finding was consistent with other previously published studies, and suggests that as patients age, there is less data available for meaningful comparisons. But the mix of results in some of the data also suggests these age estimation formulae don't accurately account for individual variations. Hand-wrist age estimations are generally considered to be good in determining how much skeletal growth patients might have. But the results of this study suggest that the hand wrist by itself is not a good estimator of age, and should be combined with dental development for a more complete picture of actual age.

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Digital Craniofacial Measurement-3D Handheld Camera Is Accurate, Reliable

A. J. Kim, et al.
Orthod Craniofac Res. 2018;21:132–139.

November 22, 2019
Dr. Jin-an Jung

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They’ve recently been many developments in imaging techniques that we can use in Orthodontics. One of these is three-dimensional image of the face. Traditional three dimensional imaging of the face typically requires a large camera system of 3 parts painted with to digital cameras that take the image of a patient's facial profile at three different angles. This takes up considerable amount of space and it’s somewhat costly. This small paper looked at the alternative of using a handheld 3D camera. It was published in Clinical Orthodontics and Research and was called 'Accuracy and reliability of digital craniofacial measurements using a small format handheld 3D camera', and the leader author was Dr.Kim. The aim of this study was to measure and compare the operation measurement errors of a handheld 3D camera and conventional tripod camera imaging system and direct calliper measurement methods, which were considered to be the gold standard. They enrolled five human subjects in this study and they use direct caliper measurements and digital measurements from the conventional and handheld 3D facial cameras. A total of 30 sets of evaluations in measurements were completed by 2-examiners using 3 different methods. These were the direct calliper measurement, three dimensional handheld camera images, and finally conventional tripod 3D camera images. They did a predetermined set of measurements for each of the imaging techniques and direct measurement using the callipers. They analyzed the measurement error and the amount of error statistically at the end of the study. Firstly they found that the intraclass correlation coefficients were vary high between the three methods of measurement. When they looked at the amount of a between the different techniques, they found that the both of handheld camera on the conventional camera methods yielded similar values for most measurements, and the average error was 0.03mm, which must be clinically insignificant. The overall conclusion was that the cheaper and simpler 3D handheld camera when compared to both direct calliper and conventional 3D tripod camera system was able to accurately and reliably provide linear distance measurements based on facial anatomic landmarks. This was a very simple and straight-forward study that really shows us that new potentially cheaper and less complex 3D imaging methods are accurate and it certainly accurate enough for most of all uses in clinical diagnosis and in research. This certainly may not even more orthodontist to adopt 3D imaging technology and it is nice to see that small simple studies are providing us with really helpful information that we may use as clinicians.

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Progressive Condylar Resorption in Orthographic Surgery Reviewed

Valthierre Nunes de Lima et al
Journal of Cranio-Maxillo-Facial surgery 2018;46;668-673

December 6, 2019
Dr. Dongwook Kim

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Condylar resorption is a disturbing development that most frequently occurs in our orthognathic surgery patients. Self-limiting or physiologic condylar remodeling generally may occur, but it usually is not clinically significant. But, progressive, pathologic resorption can cause relapse, decrease posterior facial height, anterior open bite, and temporal mandibular disfunction. The etiology of progressive condylar resorption in surgical patients is uncertain. A study that examine some aspects of this perplexing condition was published in the April, 2018 issue of the Journal of Cranio-Maxillo-Facial Surgery. The paper's lead author was Dr. Nunes de Lima, and was titled “Evaluation of condylar resorption rates after orthognathic surgery in class 2 and 3 dentofacial deformities: A systematic review” The investigators' objective was to assess the literature pertaining to condylar morphological changes following orthognathic surgery involving a sagittal split ramus osteotomy, with or without maxillary surgery. A systematic review was performed utilizing three databases to search for studies of symmetrical, skeletal class 2 or 3 subjects who received a sagittal split ramus osteotomy. All osteotomies were fixated with screws and/or plates to advance or setback their mandibles. Comparisons were done between the surgery for mandibular advancement, mandibular setback, screw or plate fixation, and whether a Le Fort 1 osteotomy was performed with the outcome of condylar resorption rate and relapse. After screening of 636 initially identified articles, 6 papers were selected for qualitative analysis. No articles were selected for quantitative analysis because of insufficient data. A total of 404 condyles were evaluated in 202 patients who had a mean age of 23.3 years. The post-operative evaluations range from 12 to 16 months after surgery, 5 of the studies utilized CBCT imaging and one used panoramic radiography. After data analysis, the authors reported that the incidence rate of condylar resorption described in the selected studies varied from 0% to 4.2%. The incidence of condylar resorption and magnitude of relapse was small in both mandibular advancements and mandibular setbacks. The incidence of condylar resorption was independent of whether maxillary Le Fort 1 surgery was performed. The incidence of condylar resorption trended higher in skeletal class 2 subjects. The type of surgical fixation utilized did not significantly influenced the condylar resorption incidence. The authors concluded that progressive condylar resorption and surgical relapses occurred in a small percentage of surgical patients receiving a sagittal split osteotomy. Within apparent trend of higher rates of resorption in skeletal class 2 subjects, only three of the studies were prospective in design and random-controlled trials were lacking. Thus, the clinical significance of the results of this systematic review are limited. Previous studies have identified a combination of mandibular retrognathia in females, pre-treatment condylar atrophy, and subsequent condylar displacement as risk factors for pathological condylar resorption which was supported by one of the papers included in this review. I look forward to longer term, well-designed future trials to help clarify the risk factors, etiology, and potential treatments for this damaging condition. If interested, the complete paper is published in the April 2018 issue of the Journal of cranio-maxillo-facial surgery.

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