DEVELOPMENT OF A CLINICALLY VALIDATED BULK FAILURE TEST FOR CERAMIC CROWNS
DEVELOPMENT OF A CLINICALLY VALIDATED BULK FAILURE TEST FOR CERAMIC CROWNS
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DOI：
10.1016/s0022-3913(10)60129-1
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发表时间：
2010-10-01
影响因子：
4.6
通讯作者：
Vailati, Francesca
中科院分区：
文献类型：
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作者：
Kelly, J. Robert;Rungruanganunt, Patchnee;Vailati, Francesca
问题陈述。传统的陶瓷冠测试产生的应力状态和损伤模式与临床上看到的有很大不同。需要开发和沟通一种临床有效的体外测试方案。本研究的目的是开发一种陶瓷单元体假体的体外失败测试，复制临床失败假体中观察到的失败机制和应力状态。本文首先通过对临床失败冠的检查、有限元分析(FEA)和临床研究的数据，比较了传统的陶瓷冠载荷失效试验的特点和越来越多关于失效来源和失效时的应力状态的证据。基于这一分析，系统地开发了一种实验技术，并确定了测试材料，以在体外重现临床失败的关键方面。材料和方法。一种潜在的牙本质类似材料(一种填充编织玻璃纤维的环氧树脂，NEMA等级G10)被评估了钝性接触的弹性模量和与树脂水泥的粘结强度，并与水化的牙本质进行了比较。测试了两种不同弹性模数的基底(镍、铬和树脂基复合材料)对破坏载荷的影响。考察了水在储存和装载过程中(单调和循环)的影响。加载活塞材料(G10、铝、不锈钢)和活塞设计多种多样，以消除赫兹裂纹并提高性能。测试从单层陶瓷(白榴石填充玻璃)扩展到双层陶瓷系统(玻璃渗透氧化铝)。检验循环频率对平均破坏载荷(2 Hz、10 Hz、20 Hz)的影响，并对极值进行统计学比较(t检验；α=.05)。破坏载荷受基层弹性模数的影响较大(t检验，P
Statement of problem. Traditional testing of ceramic crowns creates a stress state and damage modes that differ greatly from those seen clinically. There is a need OD develop and communicate an in vitro testing protocol that is clinically valid.Purpose. The purpose of this study was to develop an in vitro failure test for ceramic single-unit prostheses that duplicates the failure mechanism and stress state observed in clinically failed prostheses. This article first compares characteristics of traditional load-to-failure tests of ceramic crowns with the growing body of evidence regarding failure origins and stress states at failure from the examination of clinically failed crowns, finite element analysis (FEA), and data from clinical studies. Based on this analysis, an experimental technique was systematically developed and test materials were identified to recreate key aspects of clinical failure in vitro.Material and methods. One potential dentin analog material (an epoxy filled with woven glass fibers; NEMA grade G10) was evaluated for elastic modulus in blunt contact and for bond strength to resin cement as compared to hydrated dentin. Two bases with different elastic moduli (nickel chrome and resin-based composite) were tested for influence on failure loads. The influence of water during storage and loading (both monotonic and cyclic) was examined. Loading piston materials (G10, aluminum, stainless steel) and piston designs were varied to eliminate Hertzian cracking and to improve performance. Testing was extended from a monolayer ceramic (leucite-filled glass) to a bilayer ceramic system (glass-infiltrated alumina). The influence of cyclic rate on mean failure loads was examined (2 Hz, 10 Hz, 20 Hz) with the extremes compared statistically (t test; alpha=.05).Results. Failure loads were highly influenced by base elastic modulus (t test; P