中文摘要：

目的：通过建立4种植体支持的下无牙颌覆盖义齿的三维有限元模型,分析不同受力方式下Locator与球帽2种连接方式对下颌骨、种植体及基台应力分布的影响。方法：采集下无牙颌患者的锥形束CT（cone beam computerized tomography,CBCT）数据,应用Mimics、Gomagic Studio、SolidWorks软件分别建立Locator与球帽2种连接方式种植覆盖义齿的三维有限元模型,结合ANSYS软件分析其在不同受力方式下颌骨、种植体及基台的应力分布情况。结果：（1）不同受力方式下,2种连接方式中种植体颈部周围及下颌骨正中舌侧下缘区皮质骨出现应力集中,而最大等效应力（von-Mises应力）位于颌骨正中舌侧下缘皮质骨区;（2）种植体的von-Mises应力集中在种植体颈部及其与附着体基台连接部;（3）同种受力方式下,Locator连接的以上应力集中区的应力均小于球帽连接。结论：（1）4种植体覆盖义齿的最大von-Mises应力位于下颌骨正中舌侧下缘区皮质骨,而非种植体颈部周围皮质骨;（2）Locator连接较球帽连接的种植覆盖义齿的von-Mises更小,更有利于牙槽骨的生理健康和种植体的长期存留。

英文摘要：

Objective：To analyze the influence of two connection ways via ball cap and Locator on stress distribution of mandible,implants and abutments under different loading modes by establishing finite element models of edentulous mandibular four-implant-supported overdenture. Methods：The cone beam computerized tomography（CBCT）data of edentulous mandibular patients were collected,and three-dimensional finite element models of implant-supported overdenture via ball cap and Locator connections were established respectively by Mimics,Gomagic Studio,SolidWorks software,and stress distribution on the mandible,implants and abutments under different loading modes was analyzed combined with ANSYS software. Results：（1）Under different loading modes,stress concentration was found on cortical bone of the neck of implants and lower margin of mandible median lingual region via the two connection ways,but the max equivalent stress（von Mises stress）was located on cortical bone of lower margin of mandible median lingual region.（2）Stress concentration was found on the neck of implants and the contact zone of implants and abutments.（3）Stress of the above areas of stress concentration via Locator connection was lower than that of ball cap connection under the same loading mode. Conclusion：（1）The max von-Mises tress of four-implantsupported overdenture is located on cortical bone of lower margin of mandible median lingual region,rather than cortical bone the neck of implants.（2）The von-Mises tress of overdenture by Locator connection is lower than that of ball cap connection;overdenture via Locator connection is more favorable to the physical health of alveolar bone and long-term persistence of implants.