倾斜基牙固定桥修复前后应力分布的各向异性三维有限元分析

目的采用各向异性的三维有限元模型，在斜向和垂直向载荷的作用下，研究固定桥修复时，倾斜基牙在修复前后应力分布的变化情况。方法采用螺旋CT扫描、自编程序和ANSYS软件建立起修复前后基牙的三维有限元模型，赋予下颌骨各向异性材料属性。并在修复前对两个基牙加载，修复后对固定桥进行加载，观察第二磨牙牙槽骨的应力分布变化情况。结果垂直向受载时．修复后倾斜基牙的应力分布改善明显，最大拉应力从修复前近中根尖（31．0Mpa）转移到修复后在近远中根尖（20．2Mpa）；斜向受载时，倾斜基牙的应力分布改变较小。结论用固定桥修复倾斜基牙可以改善倾斜基牙的应力分布，但应降低牙尖斜度，减少基牙的侧向力。

Comparative Evaluation of the Tiled Abutment Teeth Restored with or without Fixed Bridge on Stress Distribution by Anisotropic Finite Element Method

Objective To compare the tilted abutment teeth restored with or without fixed bridge on stress distribution by anisotropic finite element method when the vertical and the oblique loads are simulated. Methods Three-dimensional finite element model was constructed by using SCT image reconstruction technique, self-programming and ANSYS software with the anisotropic elasticity data. The static loads were simulated according to the restored and unrestored situation. The stress distribution and stress level of the second molar was recorded. Results When the vertical static load was simulated, the stress distribution of the tilted abutment teeth was much improved. Tensile stresses appeared dominantly on the mesial apex of the second molar (31.0 Mpa) before restoration and on the distal apex of the second molar (20.2 Mpa) after restoration. When the oblique load was simulated, the stress distribution changed a little. Conclusion The stress distribution of the tilted abutment can be improved by restorative techniques with the use of fixed bridge; however, the clinician should lower the height of the cusp to reduce the oblique load of the abutment.