种植体植入部位对全下颌种植覆盖义齿应力分布的影响

目的:对不同种植体植入部位的全下颌种植覆盖义齿及支持组织进行力学分析,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,对分别采用颏孔前和尖牙、磨牙区植入种植体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颏孔前植入的覆盖义齿对斜向载荷的抵抗性差,种植体-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,种植体和基托均有较高的应力集中。②尖牙、磨牙区植入的覆盖义齿,垂直及斜向载荷时均表现了较佳的力学特性,支持组织应力峰值位于骨维持的生理范围内。结论:磨牙区种植体的植入可增强覆盖义齿对侧向力的抵抗能力,降低种植体-骨界面应力峰值,减少机械性并发症的发生。而单纯颏孔前植入设计时,应考虑采用缓冲设计,提高覆盖义齿的远期成功率。

Influence of different location of implants on the stress distribution in mandibular implant-supported complete overdenture

Objective:To investigate the stress distribution of mandibular implant-supported complete overdenture and supporting tissue with different location of implants.Methods:By three-dimentional finite element method, the stress distribution in the supporting tissue and overdenture supported by implants located in the interforaminal region or bilateral canines and first molars area was analyzed.Results:The overdenture supported by implants located in the interforaminal region showed poor oblique loading resistance, the peak value of stress in implant-bone interface was 2.4-9.2 times higher than that of vertial loading. Under vertical or oblique loading conditions, there was higher stress concentration in implants and base plates. The overdenture supported by implants located in bilateral canions and first molars area manifested better mechanical characteristic, the peak value of stress in supporting tissue was in the physiological range of bone.Conclusion:The location of implants in molar area can enhance the ability of overdenture to resist oblique loading, reduce the peak value of stress in implant-bone interface.