Dictation - 전남대학교 치과대학 교정과 대학원 세미나

A Clinical Study of Glass Ionomer Cement Oliveira SR. Eur J Orthod 2004;26:185-189. March 4, 2005 Dr. Gwang-Tak, Koh
[초벌원고] There seems to be continued interest in using glass ionomer cement to bond orthodontic brackets. There were a few studies in the late '90s. That showed low bracket failure rates for glass ionomer adhesives when followed for 8-12 months. A recent study from Brazil published in the April 2004 issue of the European Journal of Orthodontics. Looked at the bracket failure rate of glass ionomer cement up to 24 months. The study’s titled “A Clinical Study of Glass Ionomer Cement.”	[수정원고] There seems to be continued interest in using glass ionomer cements to bond orthodontic brackets. There were a few studies in the late '90s that showed low bracket failure rates for glass ionomer adhesives when followed for 8-12 months. A recent study from Brazil published in the April 2004 issue of the European Journal of Orthodontics, looked at the bracket failure rate of glass ionomer cements up to 24 months. The study’s titled “A Clinical Study of Glass Ionomer Cement.”
This project compared brackets bonded with Fuji Ortho LC glass ionomer adhesive with the composite resin control Concise. It was designed at the prospective clinical study using a split mouth design. This means that the upper left and lower right quadrant were bonded with one adhesive_either the Fuji or Concise_and the opposite quadrants were bonded with the other adhesive. This makes each patient his or her own control and assures that the brackets are compared in the same environment.	This project compared brackets bonded with Fuji Ortho LC glass ionomer adhesive with the composite resin control Concise. It was designed as a prospective clinical study using a split mouth design. This means that the upper left and lower right quadrants were bonded with one adhesive, either the Fuji or Concise, and the opposite quadrants were bonded with the other adhesive. This makes each patient his or her own control and assures that the brackets are compared in the same environment.
As I mentioned earlier one think that makes this study different from others is that the bracket failures were followed for 24 months. The other difference is that the archwire stage at the time of failure was also recorded. The archwire stages were light, medium, and heavy. The light stage was earlier alignment wires. The medium was brown stainless steel wires, and the heavy was rectangular stainless steel wires.	As I mentioned earlier one thing that makes this study different from others is that the bracket failures were followed for 24 months. The other difference is that the archwire stage at the time of failure was also recorded. The archwire stages were light, medium, and heavy. The light stage was early alignment wires. The medium was brown stainless steel wires, and the heavy was rectangular stainless steel wires.
One limitation of this study was that it only included 14 patients with a total of 242 brackets. Do you think that the brackets bonded with the glass ionomer adhesive were retained as well as those bonded with composite resin when followed for_24 months? This study found that during the light and medium archwire stages the time that would correspond with 8-12 months observation of other studies. There was no difference found between_adhesives. But when the bracket failures were followed into the later treatment stages that heavy archwire stage in this study the failure rate of glass ionomer wire brackets increase greatly. During the heavy wire phase_there were more than twice as many failures in the glass ionomer group compared to the composite resin. Overall the composite resin group had failure rated with 15% over 2 years compared to 28% in the glass ionomer group.	One limitation of this study was that it only included 14 patients with a total of 242 brackets. Do you think that the brackets bonded with the glass ionomer adhesive were retained as well as those bonded with composite resin when followed for a full 24 months? This study found that during the light and medium archwire stages the time that would correspond to the 8-12 months observation of other studie, there was no difference found between the adhesives. But when the bracket failures were followed into the later treatment stages the heavy archwire stage in this study the failure rate of glass ionomer brackets increase greatly. During the heavy wire phase, there were more than twice as many failures in the glass ionomer group compared to the composite resin. Overall the composite resin group had failure rate of 15% over 2 years compared to 28% in the glass ionomer group.
The conclusion of this study is that glass ionomer adhesives is comparable for bonding brackets during the early stages of treatment using light and medium wires. However_the failure rate for the glass ionomer adhesive appears to increase greatly during the heavy wire stages of treatment. To review this article for yourself_find a copy of the April 2004 issue of the European Journal of Orthodontics.	The conclusion of this study is that glass ionomer adhesive is comparable for bonding brackets during the early stages of treatment using light and medium wires. However, the failure rate for the glass ionomer adhesive appears to increase greatly during the heavy wire stages of treatment. To review this article for yourself, find a copy of the April 2004 issue of the European Journal of Orthodontics.

Effects of Bilateral Upper First Premolar Extraction on the Mandible Meral O, Iscan HN et al. Eur J Orthod 2004;26:223-31. March 11, 2005 Dr. Seong-Joon Park
[초벌원고] One type of Class II patient that we all see occasionally is the one where the molars are Class II. There is significant upper arch crowding, minimal lower arch crowding and no severe skeletal discrepancy. The most efficient treatment approach in these individuals, it usually to remove upper first premolars and finish the case with Class I canines and Class II molars. A study done by Lysle Johnston about ten years ago showed that Class II patients treated with upper premolar extractions actually tend to show an increase in chin projection after treatment, not a downward backward chin rotation that non-extraction advocates wanted everyone to believe.	[수정원고] One type of Class II patient that we all see occasionally is the one where the molars are Class II. There is significant upper arch crowding, minimal lower arch crowding and no severe skeletal discrepancy. The most efficient treatment approach in these individuals is usually to remove upper first premolars and finish the case with Class I canines and Class II molars. A study done by Lysle Johnston about ten years ago showed that Class II patients treated with upper premolar extractions actually tend to show an increase in chin projection after treatment, not a downward backward chin rotation that non-extraction advocates wanted everyone to believe.
So, if upper premolars combined with orthodontic treatment results in this generally positive improvement in chin position. What happens in these cases if upper premolars are removed but no orthodontic treatment is done? Will the chin still tend to rotate slightly forward? This question was investigated by researchers from Turkey in a paper called, "Effects of bilateral upper first premolar extraction on the mandible." The paper recently appeared in the April 2004 issue of the European Journal of Orthodontics.	So, if upper premolars combined with orthodontic treatment results in this generally positive improvement in chin position, What happens in these cases if upper premolars are removed but no orthodontic treatment is done? Will the chin still tend to rotate slightly forward? This question was investigated by researchers from Turkey in a paper called, "Effects of bilateral upper first premolar extraction on the mandible." The paper recently appeared in the April 2004 issue of the European Journal of Orthodontics.
The study was small involving only 26 patients divided into a treatment group and a control group. The patients were all Class II with severe upper crowding, minimal lower crowding and no significant skeletal problems. The 13 patients assigned to the extraction group had upper first premolars extracted and were observed for slightly more than one year until a handwrist radiograph indicated the pubertal growth spot was complete. The observation group had no extractions but was followed during the same period of time. Both groups had cephalometric films available from before and after the observation time. The cephalograms were superimposed using the technique described by Bj rk and the growth changes in the mandible for those received after premolar extraction were compared to the control group.	The study was small involving only 26 patients divided into a treatment group and a control group. The patients were all Class II with severe upper crowding, minimal lower crowding and no significant skeletal problems. The 13 patients assigned to the extraction group had upper first premolars extracted and were observed for slightly more than one year until a handwrist radiograph indicated the pubertal growth spurt was complete. The observation group had no extractions but was followed during the same period of time. Both groups had cephalometric films available from before and after the observation time. The cephalograms were superimposed using the technique described by Bj rk and the growth changes in the mandible for those received after premolar extraction were compared to the control group.
The results were interesting. The control group showed relatively typical growth changes during the observation time, that is the mandibular plane angle decreased slightly and the SNB increased. This would indicate slight forward mandibular growth rotation resulting in a slight increase in chin prominence. The group that received the extractions showed slightly different change. They displayed the constant mandibular plane angle and no increase in SNB, indicating no forward mandibular rotation. This study combined with previous data would seem to indicate_orthodontic treatment is necessary along with upper premolar extractions to see the forward growth rotation, thus, desired in this type of Class II patient. Perhaps, it is maintaining control of vertical molar position or obtaining proper incisor inclination through orthodontic treatment. But for whatever reason, extractions alone don't seem to result in the same mandibular changes.	The results were interesting. The control group showed relatively typical growth changes during the observation time, that is the mandibular plane angle decreased slightly and the SNB increased. This would indicate slight forward mandibular growth rotation resulting in a slight increase in chin prominence. The group that received the extractions showed slightly different change. They displayed the constant mandibular plane angle and no increase in SNB, indicating no forward mandibular rotation. This study combined with previous data would seem to indicate that orthodontic treatment is necessary along with upper premolar extractions to see the forward growth rotation that is desired in this type of Class II patient. Perhaps, it is maintaining control of vertical molar position or obtaining proper incisor inclination through orthodontic treatment. But for whatever reason, extractions alone don't seem to result in the same mandibular changes.
To read more details of this cephalometric study done in Turkey, you can find it published in the April 2004, European Journal of Orthodontics.	To read more details of this cephalometric study done in Turkey, you can find it published in the April 2004, European Journal of Orthodontics.

JCO Survey of Referring Dentists Keim RG, Gottlieb EL, et al. J Clin Orthod 2004;38(4):219-223. March 18, 2005 Dr. Hwang-Sog, Ryu
[초벌원고] What factors do you think are important to general dentists when they are considering where to refer the patients for orthodontic treatment. Is it their friendship with your orthodontist, the satisfaction of other patients for their being treated by the orthodontist, or simply the viability to offer free initial consultation?	[수정원고] What factors do you think are important to general dentists when they are considering where to refer their patients for orthodontic treatment. Is it their friendship with the orthodontist, the satisfaction of other patients that have been treated by that orthodontist, or simply the availability of a free initial consultation?
The editors of the Journal of Clinical Orthodontics, led by Doctor Robert Keim, recently published the results of the survey they conducted which said some rights on which factors are most important. The article appears in the April, 2004 issue of_JCO and is inventively titled, "JCO Survey of Referring Dentists".	The editors at the Journal of Clinical Orthodontics, led by Doctor Bob Keim, recently published the results of a survey they conducted which shed some lights on which factors are most important. The article appears in the April, 2004 issue of the JCO and is inventively titled, "JCO Survey of Referring Dentists".
The authors originally sent out 5,000 surveys to_random samples of the American Dental Association members and then sent out_additional 2,500 about two months later. One can assume the response to the initial mailing would be less than a half poll. Of the 7,500 total surveys mailed, 539 were returned and included in the results. This was response rate of 7.2 percents. The authors acknowledged this low response rate makes this more of an opinion survey than a true scientific sampling.	The authors originally sent out 5,000 surveys to a random sample of the American Dental Association members and then sent out an additional 2,500 about two months later. One can assume the response to the initial mailing would be less than was hoped for. Of the 7,500 total surveys mailed, 539 were returned and included in the results. This was response rate of 7.2 %. The authors acknowledged this low response rate makes this more of an opinion survey than a true scientific sampling.
The survey asked the questions about what things are important to general practitioner in the relationships with orthodontists. The results were not exactly what I would predict it. The average dentist who responded to the survey was 49 years old, had been in practice just over 20 years, and sent about 30 patients per year to the orthodontist.	The survey asked the questions about what things are important to general practitioner in their relationship with orthodontists. The results were not exactly what I would've predicted. The average dentist who responded to the survey was 49 years old, had been in practice just over 20 years, and sent about 30 patients per year to an orthodontist.
It was heartening to learn that it list this group. It wasn't the friendship with _orthodontist or the viability to offer free initial exam that is the most important in deciding where to refer. The most important factors identified were the quality of the treatment results, the satisfaction of the patients with their treatment and the reputation of the orthodontist. So it really does matter if you treat the malocclusion well and treat the patients well. Well do it.	It was heartening to learn that, at least to this group, it wasn't_friendship with the orthodontist or the availability of a free initial exam that were most important in deciding where to refer. The most important factors identified were the quality of the treatment results, the satisfaction of the patients with their treatment and the reputation of the orthodontist. So it really does matter if you treat the malocclusion well and treat the patient well while we do it.
Another factor that was very important was the communication from the orthodontist. Most dentists still preferred standard written communication by mail. And slightly more than half appreciate photographs with_letters. Few cared about seeing the models of_patient's teeth and fewer yet had any interest in receiving the copy of cephalometric tracings.	Another factor that was very important was the communication from the orthodontist. Most dentists still preferred standard written communication by mail. And slightly more than half appreciated photographs with the letters. Few cared about seeing the models of the patient's teeth and fewer yet had any interest in receiving a copy of cephalometric tracings.
What we can learn from this opinion survey of referring dentists is that it is important to get good results and_produce the satisfied patients. It is also important to communicate with_referring dentists about the treatment. Order including copies of cephalometric tracings is probably more of an annoyance than a benefit for most. The authors understand_the opinions of referring dentists vary widely and help provided_sample survey in this article that you can use to survey your own group of local referring dentists.	What we can learn from this opinion survey of referring dentists is that it is important to get good results and to produce satisfied patients. It is also important to communicate with the referring dentists about the treatment. Although including copies of cephalometric tracings is probably more of an annoyance than a benefit for most. The authors understand that the opinions of referring dentists vary widely and have provided a sample survey in this article that you can use to survey your own group of local referring dentists.
Also included in the article are a number of comments from individual respond them about specifics regarding how they choose where to refer. If you_like to see_additional information, it can be found in the April, 2004 issue of the Journal of Clinical Orthodontics.	Also included in the article are a number of comments from individual respondants about specifics regarding how they choose where to refer. If you would like to see this additional information, it can be found in the April, 2004 issue of the Journal of Clinical Orthodontics.

Comparative Study of Manual and Computerized Cephalometric Analyses Dana JM, Goldstein M, et al. J Clin Orthod 2004;38:293-296. March 25, 2005 Dr. Go-Woon, Kim
[초벌원고] About a year and_half ago, I reviewed an article with you from the European Journal of Orthodontics that showed_in general_computerized cephalometric measurements give the same results of the manual methods. Now, a study has been published by Dr_Dana and colleagues in the Journal of Clinical Orthodontics that takes another slightly different look at the question_whether computerized cephalometric programs give the same measurements study orthodontics as manual tracing in measuring.	[수정원고] About a year and a half ago, I reviewed an article with you from the European Journal of Orthodontics that showed, in general, computerized cephalometric measurements give the same result as manual methods. Now, a study has been published by Dr. Dana and colleagues in the Journal of Clinical Orthodontics that takes another slightly different look at the question of whether computerized cephalometric programs give the same measurements to the orthodontists as manual tracing in measuring.
The article is called "Comparative Study of Manual and Computerized Cephalometric Analyses" and it appeared in the cutting edge segment of JCO which is edited by Dr. Ronald Redmond. This study involved in analysis of thirty high quality lateral cephalometric films. The films were first traced and measured manually by two investigators and then scanned and analyzed by two cephalometric software programs. The software programs we studied were Dolphin Imaging 8.0 and VistaDent AT 9.0 by GAC. The investigators compared the measurements from the manual tracing methods to those obtained from the computer programs.	The article is called "Comparative Study of Manual and Computerized Cephalometric Analyses"and it appears in the cutting edge segment of JCO which is edited by Dr. Ron Redmond. This study involved the analysis of thirty high quality lateral cephalometric films. The films were first traced and measured manually by two investigators and then scanned and analyzed by two cephalometric software programs. The software programs that were studied were Dolphin Imaging 8.0 and VistaDent AT 9.0 by GAC. The investigators compared the measurements from the manual tracing method to those obtained from the computer programs.
The results of this study found again that _ in general_the computer cephalometric measurements were not statistically different from the manual measurements. Disagree with the previous reports we reviewed_and is reassuring if you are using this type of programs. There were two notable exceptions though to this no different conclusion.	The results of this study found again that, in general, the computer cephalometric measurements were not statistically different from the manual measurements. This agreed with the previous report we reviewed, and is reassuring if you are using these type of programs. There were two notable exceptions though to this no difference conclusion.
The first exception was at the measurement of the Wits analysis were significantly different between the two software programs and_manual methods. The authors found that the occlusal plane used as the reference for the Wits measurement which located differently in software programs that in the manual_method. If I recall correctly the Wits is supposed to use a functional occlusal plane defined by the molar and premolar as the references. And this likely does not coincide with the software occlusal plane_which is often determined by bisecting inside overlap. Interestingly_the previous study we reviewed also found_Wits measurement to be different between computer and manual methods. The second exception to agreement was the mandibular plane angle measurement based on gnathion. This exception only occurred in the Dolphin program and was due to the fact the Dolphin constructs this point rather than having a digitizing and constructs_ a bit higher than ideal. This results in mandibular plane measurement about two degrees different than the manual method or than the VistaDent program.	The first exception was at the measurement of the Wits analysis were significantly different between the two software programs and the manual method. The authors found that the occlusal plane used as the reference for the Wits measurement was located differently in software programs than in the manual tracing method. If I recall correctly the Wits is supposed to use a functional occlusal plane defined by the molars and premolars as the reference. And this likely does not coincide with the software's occlusal plane, which is often determined by bisecting inside overlap. Interestingly, the previous study we reviewed also found the Wits measurement to be different between computer and manual methods. The second exception to agreement was the mandibular plane angle measurements based on gnathion. This exception only occurred in the Dolphin program and was due to the fact that Dolphin constructs this point rather than having it digitized and constructs it a bit higher than ideal. This results in mandibular plane measurements about two degrees different than the manual method or than the VistaDent program.
The take_home message is that computers generally do a great job of making cephalometric measurement_ coincide with a traditional manual method. The exception is when the software constructs some other landmarks of references. In this study_ those constructions caused problems with Wits measurement in both software programs and with mandibular plane measurement in the Dolphin program. To read more about this study, take_ look at the May 2004 issue of the Journal of Clinical Orthodontics.	The take-home message is that computers generally do a great job of making cephalometric measurements that coincide with a traditional manual method. The exception is when the software constructs some of the landmarks or references. In this study, those constructions caused problems with Wits measurements in both software programs and with mandibular plane measurements in the Dolphin program. To read more about this study, take a look at the May 2004 issue of the Journal of Clinical Orthodontics.

Effect of Xylitol on Mutans Streptococci and Lactic Acid Formation in Saliva and Plaque from Adolescents and Young Adults with Fixed Orthodontic Appliances Stecksen-Blicks C, Lif Holgerson P, et al. Eur J Oral Sci 2004;112:244-248. April 1, 2005 Dr. Ji-Young, Park
[초벌원고] You have probably heard about the claimed caries reduction effect of using chewing gum containing xylitol. The proposed mechanism of action is that the xylitol has an effect on the streptomutans populations, which then shift to contain greater percentage of xylitol-resistant streptomutans, which in turn have less ability to colonize and produce acid. If this is true, xylitol intake may benefit orthodontic patients with fixed appliances.	[수정원고] You have probably heard about the claimed caries reduction effect of using chewing gum containing xylitol. The proposed mechanism of action is that the xylitol has an effect on the streptomutans populations, which then shift to contain greater percentage of xylitol-resistant streptomutans, which in turn have less ability to colonize and produce acid. If this is true, xylitol intake may benefit orthodontic patients with fixed appliances.
The xylitol could possibly reduce the numbers of streptomutans- or, at least, reduce the acid production. This question of whether daily intake of xylitol could help protect orthodontic patients against the acid production of plaque was investigated by a team of researchers in Sweden. The results of this study appear in the June 2004 issue of the European Journal of Oral Sciences in an article entitled, "Effect of Xylitol on Mutans Streptococci and Lactic Acid Formation in Saliva and Plaque from Adolescents and Young Adults with Fixed Orthodontic Appliances."	The xylitol could possibly reduce the numbers of streptomutans, or at least reduce the acid production. This question of whether daily intake of xylitol could help protect orthodontic patients against the acid production of plaque was investigated by a team of researchers in Sweden. The results of this study appear in the June 2004 issue of the European Journal of Oral Sciences in an article entitled, "Effect of Xylitol on Mutans Streptococci and Lactic Acid Formation in Saliva and Plaque from Adolescents and Young Adults with Fixed Orthodontic Appliances."
This study was well designed as a prospective, randomized, clinical trial. 56 teen-age orthodontic patients agreed to participate. They were randomly assigned to 3 study groups. Group A consisted of 23 patients that received a low dose of xylitol four times a day. Group B was another 23 patients that received a higher dose of xylitol_again four times daily. Group C was 10 patients that acted as the control group and received no xylitol. The study went on for 18 weeks with measurements done at baseline, 6 weeks, 12 weeks and 18 weeks. The measurements determined the streptomutans level in plaque and saliva, the ratio of xylitol resistant to xylitol-susceptible strains and the acid production levels of the plaque. The three groups were then compared to determine whether the intake of xylitol would be helpful in reducing streptomutans-or its acid producing ability in orthodontic patients.	This study was well designed as a prospective, randomized, clinical trial. 56 teen-age orthodontic patients agreed to participate. They were randomly assigned to 3 study groups. Group A consisted of 23 patients that received a low dose of xylitol four times a day. Group B was another 23 patients that received a higher dose of xylitol, again four times daily. Group C was 10 patients that acted as the control group and received no xylitol. The study went on for 18 weeks with measurements done at baseline, 6 weeks, 12 weeks and 18 weeks. The measurements determined the streptomutans level in plaque and saliva, the ratio of xylitol resistant to xylitol-susceptible strains and the acid production levels of the plaque. The three groups were then compared to determine whether the intake of xylitol would be helpful in reducing streptomutans, or its acid producing ability in orthodontic patients.
Do you think the intake of xylitol had an effect? The results were somewhat mixed. Xylitol in either dose did not seem to reduce the total number of streptomutans, except for a slight reduction in the low dose group at week 6. A positive result was that the streptomutans distribution did change to favor the xylitol resistant strain, which theoretically should help reduce colonization in acid production.	Do you think the intake of xylitol had an effect? The results were somewhat mixed. Xylitol in either dose did not seem to reduce the total number of streptomutans, except for a slight reduction in the low dose group at week 6. A positive result was that the streptomutans distribution did change to favor the xylitol resistant strain, which theoretically should help reduce colonization in acid production.
However, the measurements of acid production, although showing about a 10 percent decrease in both xylitol groups, did not show a statistically significant reduction in acid production compared to controls. The conclusion is that daily intake of xylitol at both doses studied was effective in changing the distribution of streptomutans to favor the xylitol resistant strain. However, this shift in streptomutans strains did not result in a statistically significant reduction in streptomutans numbers or in acid production. At this time we would have to say that daily use of xylitol to help reduce plaque acid production in orthodontic patients is probably not justified.	However, the measurements of acid production, although showing about a 10 percent decrease in both xylitol groups, did not show a statistically significant reduction in acid production compared to controls. The conclusion is that daily intake of xylitol at both doses studied was effective in changing the distribution of streptomutans to favor the xylitol resistant strain. However, this shift in streptomutans strains did not result in a statistically significant reduction in streptomutans numbers or in acid production. At this time we would have to say that daily use of xylitol to help reduce plaque acid production in orthodontic patients is probably not justified.
If you're interested in further information about xylitol and its effect on dental plaque, you can find this article in the June 2004 issue of the European Journal of Oral Sciences.	If you're interested in further information about xylitol and its effect on dental plaque, you can find this article in the June 2004 issue of the European Journal of Oral Sciences.

The Genetic Contribution to Orthodontic Root Resorption: A Retrospective Twin Study Ngan DCS, Kharbanda OP, et al. Aust Orthod J 2004;20:1-9. April 8, 2005 Dr. Jin-Hyoung, Cho