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目的分析上颌埋伏中切牙在牙合向牵引过程中,对同一位置施加不同角度各种牵引力值时,牙周组织应力分布特点并找出最适牵引力值,从而为临床正畸治疗埋伏牙提供基础理论参考。方法利用CBCT原始数据结合MIMICS和Ansys软件构建牙齿及其支持组织的三维模型。在牙齿切端沿其长轴方向进行16种工况下的力学加载:牵引力方向与牙体长轴夹角分别为100°,120°,140°和160°;加载力分别为40g,60g,80g和100g。比较不同工况下牙周膜Von Mises应力分布的特点。结果牵引方向与牙体长轴之间角度为100°时,最适应力值约为40g;成角120°时,最适应力值应小于40g;成角140°时最适应力值应接近60g;成角160°时最适应力值约为40g。结论当牵引力方向与牙体长轴间角度不变,牙周膜所受应力随着牵引力的增大而增大;当加载力值相同,随着牵引力方向与牙体长轴间夹角逐渐增大时,牙周膜所受应力和牙齿最适牵引力值并非随之递增;牵引埋伏牙最大应力值不应超过60g。
OBJECTIVE: To analyze the distribution of stress in periodontal tissues and find out the most suitable tractive force value when applying different traction angles to the same position in the process of occlusal traction, so as to provide the clinical orthodontic treatment for impacted teeth Basic theory reference. Methods The CBCT original data combined with MIMICS and Ansys software were used to construct 3D models of teeth and their supporting tissues. Mechanical loading was carried out on the incised end of the tooth along its long axis under 16 conditions: the angle between the direction of traction and the long axis of the tooth was 100 °, 120 °, 140 ° and 160 ° respectively; the loading forces were 40g, 60g and 80g And 100g. Compare the Von Mises stress distribution of periodontal ligament under different conditions. Results When the angle between the traction direction and the long axis of the tooth is 100 °, the optimum stress is about 40g. When the angle is 120 °, the optimum stress should be less than 40g. When the angle is 140 °, the optimum stress should be close to 60g ; When the angle of 160 °, the most suitable stress is about 40g. Conclusions The stress of periodontal ligament increases with the increase of traction when the direction of traction and the angle between the long axis of the tooth and the traction force increase. With the same loading force, the angle between the traction force and the long axis of the tooth gradually increases Large, the stress of the periodontal ligament and teeth optimum traction value is not increased; traction ambush teeth maximum stress value should not exceed 60g.