静态载荷下下前牙双端固定桥基牙牙周膜应力的三维有限元法分析

目的:用三维有限元法分析静态载荷下,下颌前牙固定桥基牙牙周膜的应力和应变分布规律,为固定桥的设计和制作提供理论依据。方法:建立下颌前牙双端固定桥及其支持组织的三维有限元模型并进行静态条件下的垂直及斜向加载,计算基牙牙周膜的应力和应变值,绘出牙周膜的应力分布图。结果:固定桥修复前,垂直载荷下,基牙牙周膜的应力以压应力为主,应力集中在根尖;斜向载荷下,基牙牙周膜的应力主要是拉应力和压应力,应力集中在唇、舌颈缘;固定桥修复后,基牙牙周膜的应力和应变分布规律与修复前相似,但最大应力、应变值都明显增大;牙周膜内表面的应力大于牙周膜外表面;垂直载荷时,牙周膜内、外表面的应力差异更为显著。结论:固定桥的修复基本没有改变基牙牙周膜的应力和应变分布规律,但使上述值明显增大。牙周膜具有明显的应力缓冲作用,垂直载荷作用下的应力缓冲作用比斜向载荷作用下明显。

Three-dimensional stress analysis of the periodontal ligament of mandible incisors fixed bridge abutment under static loads by finite element method

Aim: A three-dimensional finite element model of a human mandible incisors fixed bridge had been constructed to investigate stress and strain distributions of(periodontal) ligament of abutments under static loads so as to provide theoretical references of biomechanics for clinical application of fixed bridge.Methods: Finite element analysis was performed on the model under static loads with vertical and oblique directions.The stress and strain distributions were analyzed to study the biomechanical behavior of periodontal ligament of abutments.Results: Before the fixed bridge was applied,under vertical load,the high-stress region was near around the apical of periodontal ligament with mainly compressive stresses.Under oblique load,the high-stress region was near around the cervical of periodontal ligament with both tensile and compressive stresses.After the fixed prosthodontics,stress and strain distributions were similar with that when the fixed bridge was not applied.But the maximum stress,strain and displacement increased ap-(parently).The stresses in exterior surface of periodontal ligament were larger than that of interior surface;this character of periodontal ligament under vertical load was more obvious than that under oblique load.Conclusion: Fixed prosthodontics did not change the stress and strain distributions of abutment periodontal ligament but just made the values increased.Periodontal ligament had good cushioning-effect,which under vertical load was more obvious than that under oblique load.