Department of Electrical and Mechanical Engineering, Hainan University
目的 通过有限元方法分析不同大小的M/F和力对尖牙的位移和牙周膜(PDL)应力的影响。方法 根据临床CT图像构建了三维下颌模型，应用只有矫治力和有不同M/F的矫治力系统对尖牙进行平移移动的模拟计算。分析在每一种情况下尖牙的位移平移情况并推导出的最优的能实现尖牙平移的矫治力系统。结果 在所有计算中牙周膜应力均随力值的增大而增大。牙周膜应力则先随M/F的增大而减小，达到一定值后（最优M/F值）随M/F的增大而增大。尖牙的初始位移都是倾斜移动，当采用精确的最优M/F时，尖牙的初始位移最接近平移移动。结论 尖牙移动需要适合的力值，防止牙根吸收，然而平移移动需要有最佳的M/F值，且是必须在生理适合力范围内的M/F值。熟悉力和力矩对牙齿平移的影响有助于施加更加合理的矫治力系和设计更加合理的正畸器械装置。
Objective: This research aimed to study the optimum orthodontic force system in the canine’s translation by applying different magnitudes of M/F and force to study the canine’s displacement and periodontal ligament (PDL) stress. Methods: A mathematical model of mandibular anterior teeth and their periodontium tissue was developed. Orthodontic force systems without a moment and with various M/F were applied to the canine for its translation. An optimum force system was validated by carrying out a finite element analysis and applying a force system with a derived optimum M/F in each case. Results: The PDL stress increased with an increase in force magnitude in all cases. It first decreased with an increase in the M/F before the M/F reached the optimum value, and then increased with an increase in the M/F. The canine’s initial displacement was inclined, and it was most close to translation when the precise optimum M/F was applied. Conclusion: Canine’s movement requires an appropriate force to prevent root absorption, whereas the translation movement requires an optimal M/F value that must be within the physiological range. Knowing the influence of force and moment on tooth translation can help to apply more reasonable orthodontic force system and design more reasonable orthodontic device.