Molar Uprighting Spring에 의해 발생되는

치조골 내의 응력분포에 관한 광탄성학적 연구

최  진  휴

전남대학교 대학원 치의학과

(지도교수 : 김종철)

(국문초록)

본 연구는 하악 제1대구치가 상실되어 제2대구치가 근심으로 경사진 경우에 구치를 uprighting 시킬 때 치조골에 나타나는 응력분포를 분석하고자 하악 좌측부를 단순화시킨 광탄성 모형을 제작하고 Helical uprighting spring, T-loop spring, Modified T-loop spring 및 Open coil spring과 같은 4종의 molar uprighting spring을 제작하여 모형에 장착한 후 2차원 광탄성법을 이용하여 응력분포 양상을 비교 분석한 결과 다음과 같은 결론을 얻었다.

1. spring의 종류에 따른 효과에서, 4종류의 spring 모두 제2대구치의 회전중심(center of rotation)은 치조정과 치근단 사이의 치근단측 약 1/5-1/6에서 관찰되었다.

2. 4종류의 spring 모두 제2대구치의 근심치근면에 발생된 응력은 힘의 크기에서 약간의 차이를 보였지만 비교적 균일하게 분포하였다.

3. spring의 종류에 있어서, 제2대구치에 작용되는 원심 moment는 Open coil spring, Helical uprighting spring, T-loop spring 및 Modified T-loop spring의 순으로 점점 증가하여 발생하였다.

4. T-loop spring에서 정출력이 가장 크게 발생되었고 Modified T-loop spring에서는 압하력이 발생되었으며, 원심력은 Open coil spring에서 가장 크게 나타났다.

5. T-loop spring에 activation을 시행한 경우, 제2대구치의 근심 치근면에 나타나는 응력은 치근단에서 치조정으로 갈수록 증가하여 치조정에서 높은 응력집중이 관찰되었다.

A Photoelastic Study of the Stress Dsitribution in the  Alveolar Bone by Various Molar Uprightig Springs

Jin-Hugh Choi

Faculty of Dental science, Chonnam National University

Graduate School

(Directed by associated professor Jong-Chul Kim)

(Abstracts)

This study was performed to analyze the effects of forces to the alveolar bone by various molar uprighting spring such as helical uprighting spring. T-loop spring, Modified T-loop spring and open coil spring. The simplified two-dimensional photoelastic model was constructed with a lower left posterior quadrant containing the second molar, the first and second premolars and the canine, with the first molar missing. Several molar uprighting springs were fabricated from 0.017 by 0.022 inch blue Elgiloy and applied to the photoelastic model. Two-dimensional photoelastic stress analysis was performed, and the stress distribution was recorded by photography.

The results obtained were as follows ;

1. In all the kinds of the springs, the center of rotation of the mandibular second molar was oserved at the apical 1/5-l/6 between the alveolar crest and the root apex.

2. In all the kinds of the spring, the stress induced in the mesial root surface of the mandibular second molar was relatively homogeneous but there was some difference in the magnitude of the stress.

3. In the kinds of the springs, the distal crown tipping moment of the second molar was increased in turn as open coil spring, helical uprighting spring, T-loop spring, and modified T-loop spring.

4. The largest extrusive force was occurred in the T-loop spring, intrusive force was occurred in Modified T-loop spring only, and the largest distal tipping force was occurred in open coil spring.

5. In the T-loop spring with activation, the stress induced in the menial root surface of the second molar was increased gradually from the root apex to the alveolar crest and highly concentrated in the alveolar crest.