T型曲及二类颌间牵引作用下上颌三维有限元应力比较分析

Analysis of the stress distribution on maxillary and periodontal tissues under T-loop and Ⅱ elastics

目的:通过有限元分析法比较两种工况下上颌各牙齿的位移趋势和牙根及牙周支持组织内的应力分布规律,为临床治疗中合理选用矫治力系统以便有效的控制牙齿移动类型提供可靠的理论依据。方法:通过有限元方法分析标准"T"型曲打开1mm、侧切牙远中加挂二类牵引这两种矫治力作用下牙齿初始位移和牙齿及牙周支持组织的应力分布规律进行比较分析。结果:两种工况下前牙段均有伸长且各牙均表现为倾斜移动,冠部大于根部。结论:①两种工况下前牙段各牙的运动趋势和牙根表面应力分布趋势基本相同。②"T"型曲拉开1mm时和单纯挂二类时前牙段均有伸长,但伸长的程度前者超过了后者。

Objective This study was designed to investigate the stress distribution in the surface of tooth and peridental tissues and the initial displacements of tooth in the maxillary under two orthodental simulating force rectangular archwire with T loop and II class elastic used clinically by the 3-D finite element method so as to clarify the biomechanism of orthodontic tooth movement and component of optimal orthodontic force system. Methods To analyse the initial displacements and the stress distribution induced on the surface of the roots and periodontal tissues when the force and moment are loaded. Results Under two orthodental simulating force the initial displacements of the anterior teeth were similara. The anterior teeth were protracted and all the teeth took on tipping movement,with crown＇s displacement larger than root＇s. Conclusion With two Ioadings,the stress distribution and displacements of the teeth in maxillary was similar.