A Determination of the Cyclic Fatigue Crack Growth Properties of Human Teeth

人牙循环疲劳裂纹扩展特性的测定

• 批准号: 9900296
• 负责人: Dwayne Arola
• 金额: $ 3.34万
• 依托单位: University of Maryland Baltimore County
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-15 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9900296&HistoricalAwards=false
• 关键词: Determination; Cyclic; Fatigue; Crack; Growth

9900296ArolaDental restorations play an integral role in the maintenance of lifelongoral health. Consequently, the failure of dental restorations through reoccurring tooth decay, marginal discrepancies, and tooth fracture, are topics of substantial clinical significance. The objective of the research is to show that cyclic fatigue crack growth in teeth is an important and largely unrecognized mechanism that contributes to dental restoration failure. The hypothesis to be tested that that fatigue crack growth in teeth initiates at flaws introduced during cavity preparation with dental burs and is driven by cyclic mechanical and thermal loads which encompass standard oral activity. The flaw propagates until reaching a critical crack length which enables the loss of biological tooth structure or bulk fracture of the restoration. In this study the cyclic crack growth rate in human dentin and the threshold crack length will be determined from an experimental analysis conducted with four-point-bend dentin specimens. Fatigue specimens will be prepared from human teeth using a numerically controlled slicer/grinder. A pre-fatigue crack will be introduced in each specimen, prior to zero-to-maximum four point bend fatigue loading, through the application of Mode I cyclic compression. The cyclic flaw growth rate resulting from bend loading will be quantified in terms of the instantaneous crack length and maximum cyclic bend stress. Using the cumulative fatigue crack growth data obtained from experimental analysis, the parameters describing cyclic fatigue crack growth according to the Paris Law will be determined. Results from the experimental study will identify the significance of subsurface flaws introduced during cavity preparation on the fatigue life of restored teeth.

9900296造性修复体在维持终生健康中起着不可或缺的作用。 因此，牙齿修复物通过牙齿腐烂，边缘差异和牙齿骨折而失败是具有实质性临床意义的主题。 该研究的目的是表明牙齿的环状疲劳裂纹生长是一种重要且在很大程度上没有识别的机制，有助于牙齿恢复衰竭。 要检验的假设是，牙齿的疲劳裂纹生长在牙齿制备过程中引入的缺陷中引起了牙齿毛​​毛，并由循环机械和热负荷驱动，这些机械和热载荷包括标准口腔活性。 缺陷繁殖直到达到临界裂纹长度，从而使生物牙齿结构的丧失或恢复的大体断裂。 在这项研究中，人牙本质的循环裂纹生长速率和阈值裂纹长度将根据用四点弯曲牙本质样本进行的实验分析确定。 疲劳标本将使用数值切片机/磨床从人的牙齿中制备。 通过应用模式I环状压缩，将在每个样品中引入一个前弹性裂纹，在零到最大的四点弯曲疲劳加载之前。 弯曲载荷产生的环状生长速率将根据瞬时裂纹长度和最大循环弯曲应力进行量化。 使用从实验分析获得的累积疲劳裂纹生长数据，将确定描述循环疲劳裂纹生长的参数，根据《巴黎定律》。 实验研究的结果将确定在腔制备过程中引入的地下缺陷对恢复牙齿的疲劳寿命的重要性。