基于全瓷冠饰瓷厚度及基底厚度连续变化的全瓷冠三维有限元分析

摘要

目的:探讨饰瓷(牙合)面厚度和基底(牙合)面厚度双变量同时连续变化情况下全瓷冠饰瓷的应力变化情况.方法:以下领第一磨牙为例,运用逆向工程和计算机辅助设计技术建立包含两参数(饰瓷(牙合)面厚度和基底(牙合)面厚度)连续变化的有限元模型,设定饰瓷(牙合)面厚度变化范围为0.5～3 mm,肩台宽度变化范围为0.1～1 mm,并在全瓷冠远中颊尖垂直加载200 N的力,约束于牙槽骨底面,观察两因素联动变化对全瓷冠饰瓷最大主应力峰值的影响.结果:随着饰瓷(牙合)面厚度的增加,饰瓷的MPS峰值从32.048 MPa降低到11.036 MPa,下降幅度为65.56%;随着饰瓷厚度的增加饰瓷厚度变化对饰瓷应力峰值的影响在不断减小;基底(牙合)面厚度变化对饰瓷的应力峰值没有影响.结论:在全瓷冠的设计过程中可以适度增加饰瓷的厚度而减小基底的厚度.%AIM : To investigate the effect of different veneer occlusal thickness and core occlusal thickness on the stress distribution of all-ceranuc crowns using continuous variation of parameters.METHODS: This analysis was performed using afinite element mod of mandibular first molar.The range of veneer occlusal thickness waa set from 0.5 mm to 3 mm, and that of core occlusal thickness from 0.4 mm to 1.2 mm.Force of 200N was applied vertically to the surface of the tooth at mesial-distal cusp ridge on the veneer layer.The model was constrainted on the root of alveolar bone.Maximum principal stress ( MPS) was determined for the veneer.RESULTS : MPS in veneer decreased from 32.048 MPa to 11.036 MPa with the increase of veneer thickness, while changes of veneer MPS resulting from the increase of the veneer thickness grew gradually unovious.Core thickness exerts no impact on MPS of veneer.CONCLUSION : We can increase veneer occlusal thickness and decrease core occlusal thickneas properly in the process of all-ceramic crown design.