中文摘要：

目的用有限元方法模拟不同材料和形态的基底冠全瓷冠破坏过程，分析材料和形态对全瓷冠破坏机制的影响。方法分别建立均匀厚度、不均匀厚度、带颈环3种基底冠形态的氧化铝和氧化锆全瓷冠模型，用RFPA’2D有限元分析软件模拟加载后全瓷冠的破坏过程。结果6种模型均由拉应力引发破坏，裂纹始于牙尖顶的饰瓷表面，并沿基底冠与饰瓷的界面扩展。在本项研究加载条件下，仅饰瓷破坏，无基底瓷破坏，加载压强5MPa时氧化锆模型破坏，加载6MPa时氧化铝模型破坏。加载开始时有颈环模型呈现颈环处最小主应力集中，不均匀厚度基底冠模型呈现颈部最大主应力集中。结论氧化锆模型的基底瓷与饰瓷界面存在更大的应力。不均匀厚度基底冠设计未增加全瓷冠破坏的风险，有颈环基底冠模型的颈部是拉应力集中的薄弱环节。

英文摘要：

Objective To analyze the effects of core material and design on the fracture mechanism of veneered all-ceramic crowns. Methods The fracture process of 6 veneered alumina or zirconia crowns with different core design （well-distributed core, not well distributed core, and core with cervical ring） under load was analyzed by RFPA＇2D finite element analysis software. Results All the six tested crowns fractured due to tension failure, and the crack started at the porcelain in the cusp and spread along the interface between core and porcelain. Under the conditions of this test, the break was only related to the porcelain and not the core, and the crack of porcelain took place earlier in zirconia crowns than in alumina crowns. Minimum stress distribution in cervical ring core design crown and maximum stress distribution in not well distributed core design crown could be seen at the neck area. Conclusions Zirconia crowns presented greater stress at the interface between core and porcelain than alumina crowns. The not well distributed core design did not increase the rise of break. The neck area was the weak area with tensile stress concentration in the cervical ring core design.