Fatigue and the Endurance Strength of Dentin

描述：(由申请人提供)因以下原因导致的修复牙齿故障 牙齿折裂是影响终身口腔健康的主要障碍之一。和 尽管牙科器械和修复剂不断改进 材料方面，牙齿折裂一直是临床上普遍存在的问题。近期 研究表明，疲劳裂纹经常在牙本质中被发现 修复的牙齿和似乎起源于空洞表面边缘。基于 这些观察，修复的牙齿断裂被认为是发生在 疲劳的后果。牙本质中的微裂缝结合成一个单一的 循环咀嚼载荷作用下的明确裂纹与裂纹扩展 持续到一个临界长度促进牙齿断裂。这两个速度都 牙本质中裂纹的萌发和相应的牙齿修复可能性 失败，无疑都取决于牙本质的疲劳强度。然而， 目前对牙本质的疲劳强度知之甚少。 随着老化和其他过程而发生的变化。 拟议研究的一般假设是修复的牙齿折断 可归因于牙本质疲劳特性的改变 生理过程、衰老和脱矿。在确定 这些因素对机械性能的影响是一个基本的 了解牙本质的疲劳强度是必要的。具体的 有待检验的假设是，人牙本质显示出一种“耐力”。 这是循环应力的大小，低于该大小组织的疲劳破坏 不会发生。在本研究中，牛牙本质和人牙本质的疲劳强度 将使用弯曲疲劳载荷来确定。拟议中的调查 将有助于我们理解中的结构-属性关系 并为今后有关牙本质的研究提供了知识基础 物理化学变化对人体疲劳特性的影响 牙。因此，这项研究的结果可能会对 用于修复牙科的临床技术和程序。

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.