Fatigue and the Endurance Strength of Dentin

描述：（由申请人提供）修复的牙齿失效归因于 牙齿断裂是影响口腔健康的主要障碍之一。和 尽管牙科器械和修复技术不断进步， 材料，牙齿骨折仍然是一个普遍的临床问题。最近 研究表明，疲劳裂纹通常在牙本质中被识别， 恢复的牙齿，似乎起源于腔面边缘。基于 根据这些观察结果，认为修复后的牙齿断裂是由于 疲劳的后果。牙本质中的微裂纹会合并成一个 循环咀嚼载荷下的界限分明的裂纹和裂纹扩展 直到临界长度有利于牙齿断裂。这两个比率 牙本质裂纹的产生，以及相应的修复牙齿的可能性 牙本质的疲劳强度是决定牙本质失效的重要因素。然而，在这方面， 目前对牙本质的疲劳强度了解甚少， 随着年龄增长和其他过程发生的变化。 这项研究的一般假设是， 是由于牙本质的疲劳特性的变化， 生理过程、衰老和脱矿物质。在确定 这些因素对机械性能的影响，一个基本的 需要了解牙本质的疲劳强度。具体 要检验的假设是人类牙本质表现出“耐久强度”， 其是循环应力的量值，低于该量值，组织的疲劳失效 不会发生。本研究对牛牙本质和人牙本质的疲劳强度进行了研究 将使用弯曲疲劳载荷确定。拟议的调查 将有助于我们理解结构-性质关系， 牙本质，并为未来的研究提供知识基础 物理化学变化对人体疲劳特性的影响 牙齿.因此，这项研究的结果可能会对 用于牙科修复的临床技术和程序。

DESCRIPTION: (provided by applicant) Restored tooth failures attributed to tooth fracture are one of the primary obstacles to life long oral health. And despite progressive improvements in dental instruments and restorative materials, tooth fractures have remained as a prevalent clinical issue. Recent studies have shown that fatigue cracks are often identified in the dentin of restored teeth and appear to originate from the cavosurface margin. Based on these observations, restored tooth fracture is believed to occur as a consequence of fatigue. Microcracks in the dentin coalesce into a single well-defined crack under cyclic masticatory loads and crack propagation continues until a critical length facilitates tooth fracture. Both the rate of crack initiation in dentin, and the corresponding likelihood of restored tooth failure, are undoubtedly dependent on the fatigue strength of dentin. However, there is currently little understanding of the fatigue strength of dentin and the changes that occur with aging and other processes. The general hypothesis of the proposed research is that restored tooth fracture is attributed to changes in the fatigue properties of dentin that occur with physiological processes, aging, and demineralization. Prior to determining the influence of these factors on mechanical properties, a fundamental understanding of the fatigue strength of dentin is needed. The specific hypothesis to be tested is that human dentin exhibits an "endurance strength" which is a magnitude of cyclic stress below which fatigue failure of the tissue will not occur. In this study the fatigue strength of bovine and human dentin will be determined using flexural fatigue loading. The proposed investigation will contribute to our understanding of the structure-property relationships in dentin, and provide a foundation of knowledge for future studies regarding the influence of physical and chemical changes on the fatigue properties of human teeth. Therefore, results from this study could have tremendous impact on the clinical techniques and procedures used for restorative dentistry.