三维有限元分析前牙区单端固定桥及骨组织的应力与应变

背景：单端固定桥在临床修复牙列缺损时，对于种植体和桥体的数量、位置以及受力情况方面还存在一些争议。目的：通过三维有限元方法分析前牙区单端固定桥的受力情况。方法：应用计算机模拟三维有限元的方法，对种植体支持的固定义齿进行有限元分析，不同数量种植体以及种植体位于固定桥不同位置时，种植体及其周围骨组织的应力应变情况，为临床提供指导意义。结果与结论：①当加载力量及角度相同的情况下，随种植体数量减少或桥体长度增加，种植体及周围骨质的最大等效应力值逐渐增大，最小安全系数逐渐减小。当加载角度为22.5°时，种植体及周围骨质的最大应力值最小，最小安全系数为所有加载角度的最大，随着角度的继续增大，种植体及周围骨质的最大应力逐渐增大，最小安全系数又逐渐减小。②单端桥修复前后应力分布不均，基牙骨支持组织的应力均集中于其颈部。③3个单位缺牙区域，基牙数越多，修复成功率越高。合理选择单端固定桥和双端固定桥的修复设计是治疗成功的关键。

Stress and strain of anterior region cantilever fixed partial denture and bone tissue: Three-dimensional finite element analysis

BACKGROUND:There are still some controversies for the number, position as well as the force of the implants and the bridge during the clinical repairing of dentition defects with cantilever fixed partial denture.   OBJECTIVE:To analyze the force conditions of anterior region cantilever fixed partial denture with three-dimensional finite element. METHODS:The computer was used to simulate the three-dimensional finite element method to analyze the implant-supported fixed dentures, as well as the stress and strain status of implants and surrounding bone tissues with different numbers and different positions of implants located on the cantilever fixed partial denture, in order to provide guiding significance for the clinical application. RESULTS AND CONCLUSION:When implanted with the same load force and load angle, the maximum equivalent stress of the implants and the surrounding bone was gradually increased with the reducing of the implant number and the increasing of the bridge length, and the minimum safety coefficient was decreased gradually. When the load angle was 22.5°, implants and the surrounding bone showed the lowest maximum stress, and the minimum safety coefficient was highest. With the increasing of the load angle, the maximum stress of the implants and the surrounding bone was increased gradually, and the minimum safety coefficient was decreased. The distribution of the stress was uneven before and after repaired with cantilever fixed partial denture, and stress distribution in supporting bone of abutment mainly concentrated in neck. For the three units of edentulous area, the success rate of repairing was positively correlated with the number of abutment. Reasonable choice of cantilever fixed partial denture and rigidly fixed bridge is the key for the successful of the treatment.