骨小梁微结构对牙种植体有限元分析的影响

Influence of trabecular microstructure modeling on finite element analysis of dental implant

目的 利用显微CT和锥形束CT分别扫描建立含种植体的下颌骨三维有限元模型,比较分析骨小梁微结构对种植体骨界面力学特性分布的影响.方法 拔除比格犬下颌第三、四前磨牙后植入2枚种植体,3个月后取含种植体的颌骨标本,用显微CT和锥形束CT扫描,分别建立含种植体和骨小梁微结构、含种植体和骨小梁宏观结构的下颌骨三维有限元模型（分别简称为精确模型和简化模型）,导入Ansys 14.0软件进行有限元计算.结果 与简化模型相比,精确模型两枚种植体骨界面应力平均值明显增大,最大值变化不明显,等效应力最大值是简化模型的80％和110％,平均值是简化模型的290％和170％;而两枚种植体应变最大值和平均值均明显减小,等效应变最大值为简化模型的17％和26％,平均值为简化模型的21％和16％.简化模型种植体骨界面应力应变集中较明显;而精确模型种植体骨界面等效应力应变集中不明显、分布较均匀,主要集中于骨小梁.结论 含骨小梁微结构的精确模型可明显影响种植体骨界面应力应变的分布,骨小梁结构有分散应力和缓冲载荷的作用.

Objective To analyze the influence of trabecular microstructure modeling on the biomechanical distribution of implant-bone interface with a three-dimensional finite element mandible model of trabecular structure.Methods Dental implants were embeded in the mandibles of a beagle dog.After three months of the implant installation,the mandibles with dental implants were harvested and scaned by micro-CT and cone-beam CT.Two three-dimensional finite element mandible models,trabecular microstructure（precise model） and macrostructure（simplified model）,were built.The values of stress and strain of implant-bone interface were calculated using the software of Ansys 14.0.Results Compared with the simplified model,the precise models＇ average values of the implant bone interface stress increased obviously and its maximum values did not change greatly.The maximum values of quivalent stress of the precise models were 80% and 110% of the simplified model and the average values were 170% and 290% of simplified model.The maximum and average values of equivalent strain of precise models were obviously decreased,and the maximum values of the equivalent effect strain were 17% and 26% of simplified model and the average ones were 21% and 16% of simplified model respectively.Stress and strain concentrations at implant-bone interface were obvious in the simplified model.However,the distributions of stress and strain were uniform in the precise model.Conclusions The precise model has significant effect on the distribution of stress and strain at implant-bone interface.