无托槽隐形矫治器内收上颌前牙的三维有限元分析

Three-dimensional finite element analysis of clear aligner for retracting maxillary anterior teeth

目的:通过有限元分析探讨无托槽隐形矫治器内收上颌前牙时的生物力学特性。方法:选取1名健康青年志愿者,获取其上颌骨及牙齿CBCT影像资料,构建上颌骨复合体及无托槽隐形矫治器的三维有限元模型,分析矫治器施力控根内收(工况一)以及矫治器施力控根内收辅以微种植钉与Power arm 150 g牵引力内收(工况二)下牙齿位移趋势及牙周膜应力分布情况。结果:工况一,前牙的冠根位移差分别为113.3、92.2、128.6μm,最大牙周膜等效应力为79.6 kPa;工况二,前牙冠根位移差分别为89.3、74.3、184.2μm,最大牙周膜等效应力为37.5 kPa。结论:无托槽隐形矫治器联合微种植钉和Power arm可改善上颌切牙倾斜移动的趋势并减少牙根吸收的风险,但对于尖牙的控制尚不足。

Objective To investigate the biomechanical characteristics of the clear aligner in retracting the maxillary anterior teeth through finite element analysis.Methods A healthy young volunteer was enrolled in the study,and his CBCT images of maxilla and teeth were obtained for constructing a three-dimensional finite element model of maxillary complex and clear aligner.The teeth displacement trends and periodontal membrane stress distributions in two cases were analyzed.The orthodontic force-controlled tooth root retraction was used in case 1,while orthodontic force-controlled tooth root retraction supplemented with miniscrews implant and Power arm with 150 g traction retraction was adopted in case 2.Results In case 1,the displacement differences of the crown root of anterior teeth were 113.3,92.2,128.6μm,and the maximum periodontal membrane equivalent force was 79.6 kPa.In case 2,the displacement differences were 89.3,74.3,184.2μm,and the maximum periodontal membrane equivalent force was 37.5 kPa.Conclusion Clear aligner with miniscrews implant and Power arm can improve the tendency of tilting movement of maxillary incisors and reduce the risk of root resorption,but the control of canines is insufficient.