软衬材料固位的全下颌种植覆盖义齿三维有限元应力分析

目的 探讨弹性缓冲装置对种植覆盖义齿应力分布的影响，为优化种植覆盖义齿设计提供依据。方法 应用三维有限元法，对采用弹性软衬材料和非弹性材料固位的全下颌种植覆盖义齿进行应力分析，对比义齿本身和支持组织应力分布的差异。结果 ①无弹性材料缓冲的覆盖义齿对斜向载荷的抵抗性差，种植体颈部—皮质骨界面应力峰值为垂直载荷的2．4～9．2倍。垂直及斜向载荷，种植体及基托均有较高的应力集中。②弹性软衬材料固位的覆盖义齿，垂直及斜向载荷时，种植体—骨界面及义齿本身应力分布较均匀，避免了较大的应力集中。结论 弹性软衬材料应用于全下颌种植覆盖义齿时，表现了良好的应力缓冲作用，降低了种植体—骨界面应力峰值，减少机械性并发症的发生，有利于提高种植覆盖义齿的远期成功率。

Three-dimensional finite element stress analysis of mandibular complete implant-supported overdenture retained by soft-liner material

Objective To investigate the influence of stress- breaking elements on stress distribution of mandibular implant- supported overdenture and supporting tissue, arid to provide information for optimization of dentures design. Methods By using three- dimensional finite element method, to analyze and compare the stress distribution of the supporting tissue and overdenture retained by resilient soft - liner material or non - resilient material, Results The overdenture retained by non- resilient material showed poor oblique loading resistance. The peak value of stress between implant neck and cortical bone was 2.4 - 9.2 times higher than that of vertical loading. Under vertical or oblique loading conditions, higher stress concentrations in implants and base plates were observed, For the overdenture retained by resilient softliner material, under vertical or oblique loading condition, the stress distribution of implant - bone interface and overdenture was comparative harmonious; and avoided higher stress concentration. Conclusion Using resilient soft - liner material, mandibular implant- supported overdenture demonstrated good stress- breaking ability, reduced the peak value of stress in implant- bone interface, and decreased the mechanical compliance, which may improve the long-term success rate of overdenture.