TM种植体骨界面应力分布的有限元分析

背景：种植体形态是决定种植体骨界面应力分布的重要因素之一。探讨顺应人体正常颌骨解剖形态的TM种植体骨界面的应力分布特征对临床医生选择和设计种植体有指导意义。目的：观察集中荷载作用下TM种植体及其周围骨组织应力分布的特征。方法：通过逆向工程技术,将二维下颌骨CT图片转化为三维实体模型,并建立3种包含不同锥度的TM种植体真实下颌骨B/2类骨质的有限元模型,利用有限元技术研究两种加载方式下TM种植体骨界面应力分布特征。结果与结论：垂直加载时,对于锥度较大的TM种植体周边密质骨承受较小的应力;斜向加载时,对于锥度较大的TM种植体周边密质骨和松质骨承受较大的应力;种植体颈部,密质骨上缘与种植体接触处和种植体底部松质骨出现明显应力集中现象,斜向荷载下种植体骨界面的应力分布显著高于垂直荷载下的应力分布。从1/2长度开始变化的TM种植体骨界面在垂直荷载下表现出较好的应力分布特征。

The finite element analysis of interface stress distribution for TM implant

BACKGROUND:The morphology of implant is one of important factors determining interface stress distribution for TM implant. The TM implant bone interface stress distribution of comply with anatomic form of human normal jaw bone, which has an instructional significance for selection and design of implant of clinicians.OBJECTIVE:To observe the characteristics of the stress distribution of TM implant and its surrounding bone tissue under concentrated load.METHODS:Three-dimensional solid model of mandible has been established from two-dimensional CT pictures through reverse engineering technology. Based on three TM implants with different conical degrees, three different finite element models consisting of corresponding implants and true models of bone in B/2 type were established. The stress distribution characteristics on the bone interface of TM implant and under two different loadings were investigated by using of finite element technology.RESULTS AND CONCLUSION:The compact bone around TM implant related to a high conical degree bears smaller stresses under vertical loading, while compact bone around TM implant and cancellated bone related to a high conical degree bears the bigger stresses under oblique loading. Besides, stress concentration occurs in the contact interface of upper compact bone and implant, and the bottom of spongy bone in the neck of implant. The stress distribution of bone interface of implant was significantly higher in oblique loading condition than that in vertical loading. Bone interface of TM implant varied from 1/2 length showed a good characteristic of stress distribution under vertical loading.