螺纹种植体螺距的优化设计和应力分析

Optimized Thread Pitch Design and Stress Analysis of the Cylinder Screwed Dental Implant

目的应用AnsysWorkbenchDesignXplorer优化设计模块,探讨圆柱状V形螺纹种植体螺距变化对颌骨和种植体应力大小的影响,为临床设计和选择最佳的螺纹参数提供理论依据。方法建立了包含圆柱状V形螺纹种植体的颌骨骨块三维有限元模型,设定螺纹螺距(P)范围为0.5～1.6mm,观察P变化对颌骨和种植体Equivalen(tEQV)应力峰值的影响。结果在垂直向加载中皮质骨、松质骨和种植体的EQV应力峰值增幅分别为7.1%、123.4%和28.7%;在颊舌向加载中皮质骨、松质骨和种植体的EQV增幅分别为2.8%、28.8%和14.9%;在各种加载情况下,当变量P大于0.8mm时,对颌骨及种植体的EQV应力峰值响应曲线曲率位于-1和1之间。结论松质骨的应力大小更易受到螺距的影响;螺纹对垂直加载时的力学传递影响更明显;螺距在保护种植体垂直受力时起着更为重要的作用;圆柱状螺纹种植体螺距最佳设计应不小于0.8mm,但同时应避免过大的螺距。

Objective To determine the optimal thread pitch for an experimental cylinder implant in Ansys Workbench Design Xplorer environment. Methods Finite element models of segment jaw bone with a V-shaped thread implant were created. The thread pitch （P） was set from 0.5 mm to 1.6 mm. The maximum Equivalent stresses （EQV stresses） in jaw bone and in implant were evaluated. Results Under axial load, the amplification of maximum EQV stresses in cortical bone, cancellous bone and implant were 7.1%, 123.4% and 28.7% respectively. Under buccolingual load, the amplification of maximum EQV stresses in cortical bone, cancellous bone and implant were 2.8%, 28.8% and 14.9% respectively. When P exceeded 0.8 mm, the response curve curvature of maximum EQV stresses in jaw bone and in implant to P was ranged from -1 to 1. Conclusion Stresses in cancellous bone are more sensitive to thread pitch than in cortical bone. Stresses in jaw bone under axial load are easier affected by thread pitch than under bucco-lingual load. Thread pitch plays a greater role in protecting dental implant under axial load than under bucco-lingual load. Thread pitch exceed 0.8 mm should be the optimal design in a cylinder implant, but oversized pitch should be avoided too.