种植体螺纹位置对应力分布影响的有限元研究

目的研究集中载荷下，螺纹不同位置设计对种植体及其周围骨组织应力分布的影响，探讨种植体表面螺纹分布的优化设计。方法应用Solidworks 2005 plus自动化软件和Cosmos/works 7.0分析软件比较在垂直和斜向45°载荷下，螺纹分别位于种植体上1/3（模型A）、中1/3（模型B）、下1/3（模型C）以及遍及整个种植体（模型D）4种情况下种植体-骨界面应力分布状况。结果模型C颈部皮质骨Von-Mises应力、拉应力、压应力峰值最低，但斜向载荷下模型C种植体和松质骨应力显著高于模型A。模型B应力分布明显集中，垂直载荷下各应力均显著高于其他3种模型。模型A和D应力分布较均匀。应力集中主要出现在种植体颈部、皮质骨上缘与种植体接触处和种植体底部最下一个螺纹。斜向载荷下界面的应力显著高于垂直载荷下应力。结论螺纹位置影响种植体-骨界面的应力分布，种植体设计时应谨慎考虑，斜向载荷在种植修复中应尽可能避免。

Finite element analysis of the effects of implant thread locations on stress distribution

Objective To investigate the effects of different implant thread locations on stress distribution in implant and bone under concentrated load, and discuss the best design of location of implant thread. Methods The stress in implant-bone interface of implants with different thread locations（model A, B, C, D）, which were loaded in axial and oblique 45° to axle, were analyzed by Solidworks 2005 plus and Cosmos/works 7.0 software. Results The stresses in cervical cortical bone of implant with model C were lower than others. But under oblique load, the stresses of implant and cancellous bone in model C were higher than model A. The stresses distribution of model B was obviously concentrated, and under axial load, all kinds of stresses in this model were higher than others. The stress distribution in model A and D were more even, the stress concentrated more on implant neck, upper part of cortical bone and the lowest thread on implant. The stresses in interface under oblique load were much higher than those under axial load. Conclusion The location of thread has effect on stress distribution in implant-bone interface. More attention should be paid to it when we design implants, and we should try to avoid oblique load in implant prosthodontics.