Mini Uni Twin托槽对上尖牙远中移动影响的三维有限元分析

Three Dimensional Finite Element Analysis on Canine Distal Movement in Mini Uni Twin Brackets

目的:通过三维有限元计算Mini Uni Twin托槽系统在内收前牙时,上颌尖牙的受力及初始位移。方法:对一名志愿者进行螺旋CT扫描,建立上颌骨、上牙列以及Mini Uni Twin托槽系统的三维有限元模型。模拟临床应用摇椅弓模型进行加载,摇椅弓分别为5°和10°,并向远中分别施加50g、100g和150g的牵引力,计算摇椅弓与牵引力的合力对尖牙的作用。结果:在颌内牵引和摇椅弓的作用下,上颌尖牙的颈缘和根尖1/3唇侧出现应力集中区,其中唇侧颈缘的牙周膜应力更为集中。上颌尖牙牙冠较根尖移动距离大。结论:三维有限元能够有效地模拟Mini Uni Twin托槽系统对牙齿的影响,为临床操作提供理论依据。

Objective： To calculate the stress and initial displacement on maxillary canine by Mini Uni Twin sys-tem using three dimensional finite element. Methods： CT scanning was carried out on a volunteer, to establish athree dimensional finite element model of maxillary dentition and the Mini Uni Twin bracket system. Utility archwere 5 degrees and 10 degrees for loading simulation model. 50g, 100g and 150g were applied distally to calculatethe result of traction force on canine. Results： Stress concentration appeared in cervical and apical zone of canines,the labial cervical margin of the periodontal membrane stress is more concentrated. Conclusions： The three dimen-sional finite element can effectively simulate the effect of Mini Uni Twin brackets on the teeth.