J钩牵引方向对上颌切牙牙周膜初始应力影响的三维有限元分析

目的 分析J钩牵引方向变化对上颌切牙牙周膜应力分布的影响，探讨J钩牵引过程中的力学机制，为临床正畸提供客观的理论依据。方法 建立上颌牙齿及矫治器的三维有限元模型；在弓丝定点上以1.5 N的力保持与矢状面颊向30°不变，与牙合平面角度从0°~90°之间每5°加载一次，描绘出上颌切牙牙周膜应力图。结果 随着牵引角度增大，上切牙牙周膜压应力区由腭侧近颈缘和唇侧近根尖逐渐变为腭侧近根尖和唇侧近颈缘；牵引角度65°~75°时，中切牙牙周膜应力比较均匀，牵引角度45°~55°时，侧切牙牙周膜应力较均匀。结论 随着角度的增大，切牙由舌倾趋势变为唇倾趋势。

Three-dimensional finite element analysis of stress distribution on the maxillary incisor periodontal ligament in different traction directions with J hook

Objective To analyze the stress distribution on the maxillary incisor periodontal ligament in different traction directions with J hook.Methods Three-dimensional finite element model of the maxillary anterior teeth and appliance was established.A 1.5 N force was loaded on a chosen point on the archwire,in the direction of 30° away from the sagittal plane.A series of stress distribution maps of the periodontal ligament of the maxillary incisors were made as the force direction changs from 0°to 90°（every 5°）from occlusal plane.Results 1.As the traction angle increases,the compressive stress distribution of the maxillar incisors changed from the cervical margin area in the palatal side and the apical area in the labial side to the apical area palatally and cervical margin area labially;2.The stress of periodontal ligaments of central incisors was well-distributed between 65°~75°.However,a 45°~55°angle was more suitable for the lateral incisors.Conclusions The movement tendency of the incisors altered from lingual side to labial side as the angle increases.