上颌中切牙不同厚度Empress瓷贴面的破坏力学分析

摘要

Objective: To study the destructive process of porcelain laminate veneers with different thickness and to seek the methods to improve the strength of veneer-abutment complex. Methods: The labial-lingual sections of upper central incisors were modeled using modeling tool. Twelve models were created according to incisal design frequently used in clinic (I type, L type, U type and veneer crown type) and different veneer thicknesses (0.5mm, 1.0mm and 1.5mm). All models were analyzed using RFPA. The breakage positions and fracture loads were compared. Results: The fracture in all models first occurred in cement layer under edge to edge loads. There were significant differences in maximum loads among the models with different thickness according to ANOVA. There was no significant difference between models of 1.0mm thickness type and 1.5mm thickness type. Models of 0.5mm thickness type could support larger load than the others. Conclusions: Choosing high strength cement would improve the strength of veneer-abutment complex. Veneer would support larger edge to edge loads when preparation was limited within enamel.%目的:研究不同厚度瓷贴面的破坏过程,探讨提高贴面复合体强度的方法.方法:经软件建模工具生成上颌中切牙矢状面解剖外形.选用临床常用的4种设计外型:开窗型、对接型、包饶型和贴面冠型,结合3种贴面厚度0.5mm,1.0mm和1.5mm,建立12种模型.应用RFPA系统软件处理程序对模型进行处理.比较不同厚度的瓷贴面复合体在负荷下破损开始出现的位置和破损时负荷的大小.结果:实验结果显示,不同厚度的瓷贴面在对刃(骀)加载条件下,贴面复合体破损出现的位置都在粘接剂层.方差分析结果表明不同厚度的贴面所承受的最大负荷有明显差异.唇面预备1.0mm-1.5mm间差异无统计学意义,而这两种设计与唇面预备0.5mm均有明显差异.唇面预备0.5mm的贴面承受的最大对刃(牙合)负荷明显大于其它两种设计.结论:提高贴面复合体强度的最直接方法就是选择高强度的粘结剂,瓷贴面牙体预备应尽量控制在釉质层内.