平台转换连接对种植体-骨界面应力分布的影响

目的：探讨平台转换连接对种植体-骨界面应力分布的影响。方法：采用三维有限元分析方法,模拟建立上颌骨前牙区、种植体（直径3.5mm、长度11mm）以及修复体模型。实验模型的种植体-基台连接形式为平台转换连接,对照模型为平齐对接式连接。对模型施以100N的轴向载荷和与牙体长轴呈30°的侧向载荷,分别计算两模型种植体-骨界面的最大等效应力,并进行比较分析。结果：不同加载条件下,两模型的最大等效应力均位于种植体颈部周围颊侧皮质骨中,松质骨中应力较小;相比对照模型,平台转换连接方式的骨应力分布更均匀,且等效应力峰值较小。结论：平台转换连接可减小种植体颈周骨组织的应力,从生物力学角度考虑,建议临床上尽量选择平台转换连接式种植体。

Influence of Platform Switching Configuration on Stress Distribution in the Implant-bone Interface

Objective：To examine the influence of platform switching configuration on stress distribution in the implant-bone interface using three-dimensional finite element models. Methods：According to the experimental design,the three-dimensional finite element models were created based on the physical properties of the maxilla anterior part,implant and prosthesis. One model was implant of 3.5×11mm with a 2.5mm diameter abutment connection assuming a platform switching configuration（PLS model） . The other was implant of 3.5×11mm with a 3.5mm diameter abutment connection（normal model） . Two types of 100N loads（axial direction and 30° inclined to the long axis of the implant） were applied on the abutments supporting single tooth restorations. Values of von Mises stress at the implant-bone interface were measured by the finite element analysis. Results：Stress areas were located around the implant neck,and the highest von Mises stresses were found on the buccal face of the cortical bone. In the trabecular bone,the von Mises stresses were much lower.The PLS model provided for more favorable stress distributions and lower maximum von Mises stresses compared with the normal model with both axial and oblique loads. Conclusion：The PLS design can provide more favorable stress distributions,from a biomechanical perspective. The optimum choice was an implant with platform switching configuration.