上颌第一磨牙远中移动时牙根应力分布的三维有限元分析

目的研究上颌第一磨牙远中移动时其牙根应力分布情况，探寻上颌第一磨牙远中移动的最佳荷载方式，为正畸临床提供生物力学参考。方法采用已建立的上颌第一磨牙三维有限元模型。使用四种不同负荷方式对模型进行加载。结果上颌第一磨牙远中移动时，不同的加载所在牙根上产生应力分布不同。结论在上颌第一磨牙颊面中心附近施加远中力并结合抗衡力矩、（Mt/F=10，Mr/F=6）可以使牙根获得较平均分布的低压应力，它能使牙齿倾向于整体移动并且可以避免牙根吸收。

Analysis of Stress in the Root of the Maxillary First Molar on Distal Movement with Finite Element Method

Objective To analyze the stress distribution in the root of the maxillary first molar and to search optimal loads pattern when distal movement to provide biomechanical basis for the clinical practice. Methods Four different load patterns were added to the three-dimensional finite element model of the maxillary first molar established. Results Different loads led to different stress distributions on the roots when distal movement.Conclusion A distalizing force combined with a countertipping moment (Mt/F=10) and a counterrotation moment(Mr/F=6) could lead to a lower and uniform stress on the root and it implys a tendency of translation of the maxillary first molar and avoidance of root absorption.