Objectives: To solve the current problems of loosening and dislodging caused by the high elastic modulus of solid implants, we attempted to study a gradient porous dental implant that can lower the stress concentration and reduce the elastic modulus.
Methods: SolidWorks software was utilized to design the abutment and mechanical structure of the gradient porous implant. The mechanical properties of the gradient porous implant were evaluated by an orthogonal experimental design from four aspects: pore shape, pore diameter, porous layer height, and circumferential distribution. ANSYS software was used to evaluate the distribution of Von-Mises stress in the implant and its surrounding bone tissues under different structural combination parameters to derive the optimal combination of gradient porous implant parameters.
Results: The effects of the four factors, namely, pore shape, pore diameter, porous layer height and pore distribution, on the maximum Von-Mises stress on the implant were as follows. As the pore shape became smaller and the circumferential distribution decreased, the Von-Mises stress decreased significantly. The pore diameter went from 500 μm to 600 μm and then to 700 μm. The Von-Mises stress decreased and then increased. It increased with the increase in the height of the porous layer.
Conclusions: The final optimal combination of parameters for the gradient porous implant was as follows: square pore shape, pore diameter of 600 μm, porous layer height of 3 mm, and quadratic step in pore distribution.
目的: 为解决目前实心种植体弹性模量大而导致的松动、脱落等问题，试图研究一种拥有降低应力集中、减小弹性模量等优势的梯度多孔牙种植体。方法: 利用SolidWorks软件设计梯度多孔种植体基台和种植体的机械结构，从孔形、孔径、多孔层高度、周向分布4个方面，通过正交试验设计来评价梯度多孔种植体的力学性能。使用ANSYS软件评估不同结构组合参数下种植体及其周围骨组织的等效应力分布，得出最佳梯度多孔种植体的参数组合。结果: 孔形、孔径、多孔层高度、孔分布4种因素对种植体所受最大等效应力的影响分别为：随着孔形的变小和孔分布的减少，等效应力均呈现显著性下降的趋势；孔径从500 μm到600 μm再到700 μm，等效应力呈现先减小再增大的趋势；随着多孔层高度的增加，等效应力呈现上升的趋势。结论: 最终得到梯度多孔种植体的最佳参数组合是：孔形为正方形、孔径为600 μm、多孔层高度为3 mm、孔分布为四分步。.
Keywords: dental implants; elastic modulus; finite element analysis; gradient porous; orthogonal experiment.