膨胀式牙种植体及周围骨组织应力分布的三维有限元比较研究

A comparative study of stress distribution of expandable dental implants and surrounding bone tissues:A three-dimensional finite element analysis

目的:应用三维有限元方法,研究集中荷载作用下,不同膨胀角和膨开比例组合而成的20类牙种植体及周围骨组织的应力分布特征,确定有利于应力均匀分布的最佳组合设计。方法:通过Unigraphics NX和ANSYS Workbench软件建立某下颌磨牙种植体局部结构的三维有限元模型,对下颌磨牙施加垂向0°和斜向15°的100N咬合力,对比分析40组牙种植体及周围骨组织的应力分布情况。结果:随着膨开比例的增加,种植体、皮质骨和松质骨的最大应力基本上先减小后增大。对于种植体和皮质骨,斜向15°加载的应力显著大于0°垂向加载。而对于种植体底部和松质骨,加载方向的不同影响却不大。结论:三维有限元分析结果表明,膨胀角3°-4°、膨开比例0.375为膨胀式种植体的最佳参数。

Objective： To investigate the stress distribution of 20 expandable dental implants and their surrounding bone tissues with various expansion angle and expansion length ratio under concentrated loading based on a three-dimensional finite element method in order to determine the optimal design of stress uniform distribution. Methods： A three-dimensional finite element model of a local mandibular molar implant was obtained by Unigraphics NX and ANSYS Workbench, and a crown was applied with a 0 degree vertical or 15 degree inclined force of 100 N. The values of von Mises stress of 40 implants and the surrounding bone tissue were recorded. Results： With the increase in the expansion length ratio, the stress was essentially decreased and then increased. The stress distribution of implant and cortical bone in 15 degree incined loading condition was significantly higher than that in 0 degree vertical loading. Few influence of the stress distribution of implant bottom and cancellous bone with different loading direction was found. Conclusion： The three dimensional finite element analysis shows that the implant-bone interface stress of those with expansion angle of 3°-4° and expansion length ratio of 0.375 is optimal.