不同骨缺损类型牙种植体的三维有限元分析

目的研究动态加载下不同骨缺损类型对种植体-骨整合界面、天然骨与Bio-oss成骨结合界面应力分布的影响。方法应用ANSYS软件,建立第1磨牙缺失并伴有不同类型骨缺损(旁穿型、裂开型、环型、垂直型)的4种模型,并建立各模型对应的植骨块和种植体模型,以200 N垂直载荷及100 N斜向载荷分别模拟咀嚼周期中5个阶段的动态受力过程,分析各组织结合界面应力分布情况。结果 4类骨缺损模型在一个咀嚼周期中,从第2到第4阶段,种植体-骨整合界面应力增幅依次为81.6%、90.7%、106%、182%,Bio-oss成骨与天然骨结合界面应力增幅依次为26%、13%、6%、56%。结论 4类模型的植骨稳定性为:环型骨缺损裂开型骨缺损旁穿型骨缺损垂直型骨缺损,在临床上种植医师应根据其植骨部位甄别出植骨高风险患者,治疗时应为骨植入材料选择不同的固定方式,最终提高植骨稳定性;垂直载荷更有利于各组织结合界面的应力分布状况,在临床设计种植义齿上部结构时应尽量减小或避免斜向载荷。

Three-dimensional finite element analysis of dental implants with different bone defects

Objective To analyze the effect of different bone defect types on stress distributions of the implant- bone interface and bone-Bio-oss interface under dynamic loads by finite element method. Methods The finite element models for four types of bone defects (fenestrative bone defect, dehiscent bone defect, circular bone defect, vertical bone defect) without the first molars were established, then the models of grafting bone and implants corresponding to each model were established. The vertical load of 100 N and Oblique load of 200 N were used to simulate the dynamic chewing process of 5 stages in a masticatory cycle, and the maximum Von Mises stresses at the implant-bone interface and bone-Bio-oss interface were analyzed. Results In a masticatory cycle, from stage 2 to stage 4, the stresses on implant-bone interface increased by 81.6%, 90.7%, 182%, 106%, respectively, while the stresses on Bio-oss bone and natural bone interface increased by 26%, 13%, 6%, 56.25%, respectively. Conclusions The sequence of bone graft stability for the models with four types of bone defects is: circular bone defect> dehiscent bone defect>fenestrative bone defect>vertical bone defects. In clinic, doctors should screen the high-risk patients according to the sites of the bone grafts, and choose different methods for fixing the bone grafts so as to improve the stability of bone grafting. The axial loading will be more beneficial to the stress distributions on the interface, and the oblique loading should be decreased or avoided in clinical design for the superstructure of implant denture.