三维有限元分析牙种植体孔隙结构设计及生物力学性能

Design and biomechanical properties of dental implant pore structure based on three-dimensional finite element analysis

背景:有研究显示,在设计多孔种植体时可以通过改变孔隙内部单元结构来改变弹性模量,为更好地平衡种植体强度和弹性模量提供新的方法。目的:通过有限元分析不同微观孔结构牙种植体生物力学性能,阐明不同微观孔结构对周围骨应力和种植体力学性能的影响。方法:通过CT扫描建立下颌骨模型和3种不同孔隙结构(传统结构孔隙、复合结构孔隙、G7结构孔隙)的牙种植体有限元模型,孔隙率为40%,多孔层厚度为1.2 mm,孔径为0.45 mm,模拟极限合力状态对每个模型施加载荷,采用ANSYS有限元软件运算并分析周围骨应力及种植体的应变。结果与结论:(1)当种植体受极限合力,传统结构、复合结构与G7结构牙种植体对周围皮质骨等效应力最大值分别为38.324,56.574,64.694 MPa,对周围松质骨等效应力最大值分别为1.836,10.221,9.439 MPa,种植体等效应力最大值分别为156.38,476.23,457.76 MPa;复合结构种植体的最大周围骨应力在促进骨结合的范围内;(2)当种植体只受侧向力时,传统结构、复合结构与G7结构牙种植体应变最大值分别为2.222 9×10^(-2),1.661 9×10^(-2),3.210 9×10^(-2) mm/mm;当种植体只受轴向力时,传统结构、复合结构与G7结构牙种植体应变最大值分别为2.266 2×10^(-3),1.844 6×10^(-3),2.971 5×10^(-3) mm/mm;说明在受侧向静力载荷和轴向载荷时,复合结构种植体的应变最小,产生的微动小,有助于提高骨结合效果;(3)结果表明,随多孔种植体内部孔隙单元结构的变化,周围骨应力发生明显变化,种植体力学性能也发生明显变化,种植体表面多孔结构的单元胞体结构形状的改变显著影响弹性模量和种植体的力学性能,复合孔隙结构的牙种植体与传统结构和G7结构相比具有更好的生物力学性能。

BACKGROUND: Studies have shown that the elastic modulus can be changed by changing the pore internal unit structure when designing porous implants, providing a new way to better balance implant strength and elastic modulus.OBJECTIVE: To analyze dental implant biomechanical properties with different micro pore structures by finite element analysis so as to elucidate the effects of different micro pore structures on the surrounding bone stress and implant physical properties.METHODS: A mandibular model and three finite element models of dental implants with different pore structures(conventional structural pores, composite structural pores, and G7 structural pores) were built by CT scanning with porosity of 40%, the thickness of the porous layer of 1.2 mm, and the pore size of 0.45 mm. The ultimate force state was simulated to apply load to each model, which was operated by ANSYS finite element software and analyzed by surrounding bone stress and strain of the implants.RESULTS AND CONCLUSION:(1) When implants were subjected to the ultimate force, the maximum values of effector forces such as 38.324, 56.574, 64.694 MPa for conventional structure, composite structure and G7 structure dental implants on the surrounding cortical bone were respectively 1.836, 10.221, 9.439 MPa, and the maximum values of effector forces such as implants were 156.38, 476.23, 457.76 MPa. The maximum surrounding bone stress of the composite structure implant was within the range of promoting osseointegration.(2) When only lateral forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.222 9×10^(-2), 1.661 9×10^(-2), 3.210 9×10^(-2) mm/mm. When only axial forces were applied to the implants, the maximum strain values of dental implants placed in the conventional structure, composite structure and G7 structure were 2.266 2×10^(-3), 1.844 6×10^(-3), 2.971 5×10^(-3) mm/mm, indicating that when subjected to lateral static load and axial load, the strain of the composite structure implant was smallest and the micro-movement was small, which helped to improve the osseointegration effect.(3) The results showed that the surrounding bone stress changed significantly with the change of pore unit cell structure inside the porous implant, and the mechanical properties of the implant also changed, and the change of unit cell structure shape of the porous structure on the implant surface significantly affected the elastic modulus and the mechanical properties of the implant. Dental implants with a composite pore structure had better biomechanical properties compared with conventional constructs and G7 constructs.