不同切端设计类型瓷贴面的三维有限元应力分析

Stress distribution on porcelain laminate veneers of different designs

目的 应用三维有限元法分析不同切端设计瓷贴面的应力分布。方法 将上中切牙用环氧树脂包埋 ,精密机床逐层切削 ,数码成像。用 pro -engineer软件生成瓷贴面模型 ,用pro -mechanica软件进行有限元分析。结果 切端包绕型和切端对接型瓷贴面在对刃牙合加载条件下 ,其切端的应力值均为最高值。在正常覆牙合加载时切端对接型瓷贴面的颈部内侧出现一高应力区 ,而切端包绕型瓷贴面未出现。在正常覆牙合加载状态下 ,切端包绕型瓷贴面的应力值明显低于切端对接型 ;在对刃牙合加载时 ,二者应力值接近 ;在深覆牙合加载时 ,切端对接型瓷贴面的应力值较切端包绕型低。结论 在三种加载条件下 ,切端包绕型与切端对接型瓷贴面的应力分布不同。

Objective To study the stress distrib ut ion of porcelain laminate veneers of different designs by using three-dimensiona l finite element method.Methods The permament upper center incisor embeded in epo xyresin was ground by a numerical controlled lathe machine in 100μm per layer.T hen digital photograph of each layer was taken and input into computer. The two -dimensional sections were reconstructed into three-dimensional porcelain venee r model by using AUTOCAD 2000, PRO-ENGINEER 2001 software. The stress distribut ion was analyzed by three- dimensional finite element method of pro-engineer sof tware.Results Overlapped and feathered incisal design showed h igher stress at the edge to edge occlusion.Only feathered incisal design showed a high stress area at the inner cervix. Overlapped incisal design showed lower s tress than feathered incisal design at normal bite occlusion,while the result wa s opposite at overbite occlusion,and their stress was close to each other at the edge to edge occlusion. Conclusion Overlapped incisal design and feathered incisa l design shows differenct stress at three kind of occlusion. At normal bite occl usion feathered incisal design has a high stress at the inner cervix.