Use of contact testing in the characterization and design of all-ceramic crownlike layer structures: A review
Use of contact testing in the characterization and design of all-ceramic crownlike layer structures: A review
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DOI：
10.1067/mpr.2001.119581
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发表时间：
2001-11-01
影响因子：
4.6
通讯作者：
Thompson, VP
中科院分区：
文献类型：
--
作者：
Lawn, BR;Deng, Y;Thompson, VP
陶瓷基冠，特别是磨牙冠，在持续的咬合接触中，可能会由于骨折的积累和其他损伤而过早失效。损伤模式取决于陶瓷类型（尤其是微结构）、缺陷状态、加载条件和几何因素。这些损伤模式可以在实验室中模拟和表征，使用赫兹接触测试对单层、双层和三层结构进行测试，以代表口腔功能中冠反应的重要方面。本文综述了在全瓷冠寿命的背景下，目前与临床相关的瓷基层结构接触性损伤的牙科材料知识库。提出了简单的接触测试方案，利用模型平面，陶瓷基层结构的球体压头-陶瓷/聚合物双层（模拟牙本质上的整体陶瓷冠）和陶瓷/陶瓷/聚合物三层（模拟牙本质上的贴面/核心全陶瓷冠）-可以提供有用的关系预测临界咬合载荷诱发终身威胁的断裂。结果表明，对于厚度远低于1 mm的陶瓷层，来自下芯层表面的径向开裂是主要的破坏模式。这种方法可以为设计下一代冠层结构建立科学的、基于材料的基础。
Ceramic-based crowns, particularly molar crowns, can fail prematurely from accumulation of fracture and other damage in continual occlusal contact. Damage modes depend on ceramic types (especially microstructures), flaw states, loading conditions, and geometric factors. These damage modes can be simulated and characterized in the laboratory with the use of Hertzian contact testing on monolayer, bilayer, and trilayer structures to represent important aspects of crown response in oral function. This article reviews the current dental materials knowledge base of clinically relevant contact-induced damage in ceramic-based layer structures in the context of all-ceramic crown lifetimes. It is proposed that simple contact testing protocols that make use of sphere indenters on model flat, ceramic-based layer structures-ceramic/polymer bilayers (simulating monolithic ceramic crowns on dentin) and ceramic/ceramic/polymer trilayers (simulating veneer/core all-ceramic crowns on dentin)-can provide useful relations for predicting critical occlusal loads to induce lifetime-threatening fracture. It is demonstrated that radial cracking from the lower core layer surface is the dominant failure mode for ceramic layer thicknesses much below I mm. Such an approach may be used to establish a scientific, materials-based foundation for designing next-generation crown layer structures.