动态载荷下单端桥基牙牙周膜应力的三维有限元分析  

Three-dimensional finite element analysis of the stress in abutment periodontal ligament of cantilever fixed bridge under dynamic loads

作　　者：郭莹[1] 唐亮[1] 潘燕环[2] 

机构地区：[1]暨南大学医学院口腔系,广东广州510632 [2]暨南大学理工学院力学与土木工程系

出　　处：《中华口腔医学杂志》2009年第9期553-557,共5页Chinese Journal of Stomatology

基　　金：广东省自然科学基金（31912）

摘　　要：目的采用瞬间动态分析以Г56为基牙修复Г7缺失的单端桥修复前后的三维有限元模型，在不同部位加载下基牙牙周膜的应力状况及分布规律，以期寻求更接近咀嚼过程的生物力学数据。方法在动态载荷周期内对三维有限元模型施以250N平均骀力作为不同加载部位和方向的动态载荷，应用ANSYS软件计算基牙牙周膜在动态载荷下的应力，绘制牙周膜的应力-时间曲线。结果基牙牙周膜的应力随着加载、卸载时间的积累逐渐加大，斜向加载时达到1个动态载荷周期的应力峰值（例如修复后载荷作用于Г567，0.260s时Г5牙周膜的von Mises应力值为7.936MPa）；修复后的最大应力多位于近缺隙侧基牙的牙周膜上[例如修复后载荷作用于Г567，0.260s时Г6牙周膜的von Mises应力值为18.483MPa，远高于Г5牙周膜的von Mises应力值（7.936MPa）]；修复前后基牙牙周膜在1个动态载荷周期中主要表现为压应力明显高于拉应力，但随着修复后承受载荷牙齿数目的减少，Г5牙周膜的近中颈缘则产生相反的结果，呈现出显著的拉应力；观察连续3个动态载荷周期后发现，后一个周期基牙牙周膜的应力值均比前一个周期有所增加，但应力值的增长并不明显。结论在下颌后牙单端桥的咀嚼运动中，侧向骀力对基牙牙周健康影响最大；修复后对近缺隙侧基牙的牙周组织条件要求更高；连续多个动态载荷周期加载下牙周膜形成的应力积累不会对牙周膜造成损害，修复第二磨牙缺失的双基牙单端桥设计是可行的。Objective To analyze the stress distribution in the abutment periodontal ligament of posterior cantilever bridge under transient dynamic loads using a three-dimensional finite element （FE） model. Methods A cantilever bridge using Г5, Г6 as abutments to restore missing Г7 was designed, and its FE model was established and loaded with dynamic loads. The loads were set as 250 N ocelusal forces loaded at different positions on the cantilever, and in different directions to simulate the mastieatory cycle. FE analysis was conducted on the ANSYS to analyze stress distributions in abutment periodontal ligament under dynamic loads. Stress-time curves were traced to understand the biomechanical behavior of abutment periodontal ligament. Results With loading and unloading time accumulated, the stress value in the abutment periodontal ligament increased gradually. Loads in lateral direction induced peak value stress in a masticatory cycle. There was little residual stress in the end of unloading phase. The maximum stress concentrated in abutment periodontal ligament adjacent to the missing tooth. Without restoration abutment periodontal ligament was mainly under compressive stress. However, when Г7 was restored with a cantilever bridge, tensile stress was shown in the mesial cervical area of Г5, Three masticatory cycles were simulated, and stress values in abutment periodontal ligaments increased with the number of masticatory cycles. But the differences of the stress between different masticatory cycles were not significant. Conclusions In the mastication movement, lateral loads induce maximum stress in abutment periodontal ligament. Cantilever fixed bridge design is more demanding for the periodontal condition of the abutment adiacent to the missing tooth than for the other abutment. When loaded with continuous masticatory force, the stress concentration does not increase significantly. Therefore, cantilever bridge is one of the feasible choices to restore missing lower second molar.

关 键 词：义齿 局部 固定 有限元分析 牙周膜 动力分析 

分 类 号：R686[医药卫生—骨科学]