Age-related transparent root dentin: mineral concentration, crystallite size, and mechanical properties
Age-related transparent root dentin: mineral concentration, crystallite size, and mechanical properties
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DOI：
10.1016/j.biomaterials.2004.09.004
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发表时间：
2005-06-01
期刊：
影响因子：
14
通讯作者：
Ritchie, RO
中科院分区：
文献类型：
--
作者：
Kinney, JH;Nalla, RK;Ritchie, RO
许多骨折发生在已经改变的牙齿上，例如修复或牙髓修复。因此，有必要评估这些改变的牙本质的结构和力学性能。其中一种改变的牙本质是透明（有时称为硬化）牙本质，它随着年龄的增长而逐渐形成。本研究的重点是正常牙本质和透明牙本质在结构和力学性能上的差异。通过x射线计算机微断层扫描测量，矿物质浓度在透明牙本质中明显较高，浓度升高与小管管腔闭合一致。通过小角度x射线散射测量的晶体尺寸在透明牙本质中略小，尽管这一发现的重要性需要进一步研究。透明后，弹性性能不变；然而，与正常牙本质不同，透明牙本质在失效前几乎没有屈服。此外，在高应力水平下，断裂韧性降低了约20%，而疲劳寿命受到了有害影响。这些结果在透明牙本质的微观结构改变方面进行了讨论。(C) 2004 Elsevier Ltd.版权所有。
Many fractures occur in teeth that have been altered, for example restored or endodontically repaired. It is therefore essential to evaluate the structure and mechanical properties of these altered dentins. One such altered form of dentin is transparent (sometimes called sclerotic) dentin, which forms gradually with aging. The present study focuses on differences in the structure and mechanical properties of normal versus transparent dentin. The mineral concentration, as measured by X-ray computed microtomography, was significantly higher in transparent dentin, the elevated concentration being consistent with the closure of the tubule lumens. Crystallite size, as measured by small angle X-ray scattering, was slightly smaller in transparent dentin, although the importance of this finding requires further study. The elastic properties were unchanged by transparency; however, transparent dentin, unlike normal dentin, exhibited almost no yielding before failure. In addition, the fracture toughness was lowered by roughly 20% while the fatigue lifetime was deleteriously affected at high stress levels. These results are discussed in terms of the altered microstructure of transparent dentin. (C) 2004 Elsevier Ltd. All rights reserved.