基于生物学反应考量的下牙列轻力远移的有限元分析

Finite element analysis of lower arch en-massedistalization with light force with biological response consideration

目的对于正畸矫治而言,牙齿在正畸力作用下的长期移动分析较以往的正畸加力瞬时位移更有临床意义.本研究通过基于自动迭代计算的有限元分析方法探究轻力颌间牵引的作用下下牙列远中移动时的趋势.方法本有限元研究搭建包括了下牙列、牙周膜、直丝弓矫治器的有限元模型.模拟50g的颌间轻力牵引力进行下牙列移动.通过牙周膜自动迭代计算的方法模拟牵引力长期作用下下牙齿的移动.获得每步迭代计算中牙冠、牙根标志点的三维移动量.结果本研究迭代计算200次时展示出各牙齿移动较为明显的趋势.中切牙及侧切牙均有明显的舌倾趋势,冠顶点的舌向位移分别为1.72 mm与2.26 mm.尖牙至第二磨牙均有(0.81~0.39)mm不等的远中倾斜趋势.中切牙及侧切牙均有较明显的向伸长趋势,分别为0.49 mm、0.53 mm.第二前磨牙出现了0.19 mm的压低,其余牙均有少量伸长,纵曲线加深.结论本研究初步完成了针对牙齿在正畸力作用下的长期移动的基于自动迭代计算的有限元分析方法的实现.定量地揭示了轻力颌间牵引作用下下牙列远中移动时的趋势.

Objective For orthodontic treatment,the analysis of long-term tooth movement under orthodontic force has more clinical significance than the initial displacement analyzed in previous studies.In this study,the finite element analysis method based on an automatic iterative calculation method was used to explore the distal movement trend of lower arch during continuous light force of intermaxillary traction for en-masse distalization.Methods The finite element model with lower dentition,periodontal membrane and straight wire arch appliance was constructed,and the intermaxillary traction was simulated with 50g light force.The tooth movement under long-term traction force was simulated by an automatic iterative calculation method.The three-dimensional(3D)movements of the tooth crown and root landmarks were obtained at each iteration.Results The trend of tooth displacement was obvious with 200 iterations.Both lower central and lateral incisors showed obvious lingual inclination,with the lingual displacement of the crown points of 1.72 mm and 2.26 mm,respectively.From the canine to the second molar,distal tilt ranging from 0.39 mm to O.8l mm was noticed.Both the central and lateral incisors showed an obvious extrusion,reaching 0.49 mm and 0.53 mm,respectively.The second premolar showed 0.19 mm intrusion,and the other teeth showed less extrusion,leading to a deeper Spee curve.Conclusions The finite element analysis for the long-term movement of the lower dentition under orthodontic light force was implemented based on an automatic iterative calculation method.The movement trend of lower dentition under light-force intermaxillary elastic traction was quantitatively described.