Arola Dwayne
Department of Materials Science and Engineering, University of Washington Seattle, WA, USA; Departments of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA; Departments of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA.
Dent Mater. 2017 Apr;33(4):367-381. doi: 10.1016/j.dental.2017.01.012. Epub 2017 Feb 20.
The objective of this article is to describe the importance of fatigue to the success of restorative dentistry, with emphasis on the methods for evaluating the fatigue properties of materials in this field, and the durability of their bonded interfaces.
The stress-life fatigue and fatigue crack growth approaches for evaluating the fatigue resistance of dental biomaterials are introduced. Emphasis is placed on in vitro studies of the hard tissue foundation, restorative materials and their bonded interfaces. The concept of durability is then discussed, including the effects of conventional "mechanical" fatigue combined with pervasive threats of the oral environment, including variations in pH and the activation of endogenous dentin proteases.
There is growing evidence that fatigue is a principal contributor to the failure of restorations and that measures of static strength, used in qualifying new materials and practices, are not reflective of the fatigue performance. Results of selected studies show that the fundamental steps involved in the placement of restorations, including the cutting of preparations and etching, cause a significant reduction to the fatigue strength of the hard tissue foundation. In regards to the bonded interface, results of studies focused on fatigue resistance highlight the importance of the hybridization of resin tags, and that a reduction in integrity of the dentin collagen is detrimental to the durability of dentin bonds.
Fatigue should be a central concern in the development of new dental materials and in assessing the success of restorative practices. A greater recognition of contributions from fatigue to restoration failures, and the development of approaches with closer connection to in vivo conditions, will be essential for extending the definition of lifelong oral health.
本文旨在阐述疲劳对修复牙科学成功的重要性，重点介绍评估该领域材料疲劳性能的方法及其粘结界面的耐久性。
介绍了用于评估牙科生物材料抗疲劳性的应力-寿命疲劳和疲劳裂纹扩展方法。重点是对硬组织基础、修复材料及其粘结界面的体外研究。接着讨论了耐久性的概念，包括传统“机械”疲劳的影响以及口腔环境中普遍存在的威胁，如pH值变化和内源性牙本质蛋白酶的激活。
越来越多的证据表明，疲劳是修复体失败的主要原因，并且在鉴定新材料和实践中使用的静态强度测量方法并不能反映疲劳性能。所选研究结果表明，修复体放置过程中涉及的基本步骤，包括制备洞形的切割和酸蚀，会显著降低硬组织基础的疲劳强度。关于粘结界面，专注于抗疲劳性的研究结果突出了树脂突杂交的重要性，并且牙本质胶原蛋白完整性的降低对牙本质粘结的耐久性有害。
在新型牙科材料的开发以及评估修复实践的成功方面，疲劳应成为核心关注点。更深入认识疲劳对修复失败的影响，并开发与体内条件更紧密相关的方法，对于扩展终身口腔健康的定义至关重要。
