目的利用有限元方法,探讨使用隐形矫治方式,一步达到尖牙远中整体移动的最佳施力方法。方法模拟无托槽隐形矫治器载荷对牙裂有限元模型进行应力分析。结果计算受不同力偶作用时尖牙远中面上各点受到的平均主应力及von Mises应力的标准差。结论在对尖牙施加远中矫治力的同时施加反方向的力矩后,尖牙倾斜移动的趋势将减少。当施加的远中力与逆时针力偶的力量比例为100:125～130,即力与力矩的比例(M/F)为7.25～7.5时,尖牙根部远中面受力最为均匀,即接近整体移动。

Objective To explore the best way to make canine bodily movement distally by one step with the invisible bracketless appliances. Methods To simulate the force generated by the invisible bracketless appliance and analyze the stress distribution by the means of finite element method. Then to calculate the mean value of the main stress and Von Mises standard deviation when the canine effected by distal and mesial force (F) with different couples simultaneously and to analyze the stress distribution with different combinations of F and M ratio. Results The canine incline tends to be less by the combination of F and M with proper ratio. Conclusion When M/F=7.257.5, the canine looks more like bodily movement using the invisible bracketless appliances.