Mechanical properties of the dentinoenamel junction: AFM studies of nanohardness, elastic modulus, and fracture
Mechanical properties of the dentinoenamel junction: AFM studies of nanohardness, elastic modulus, and fracture
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DOI：
10.1002/1097-4636(200101)54:1
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发表时间：
2001-01-01
期刊：
影响因子：
--
通讯作者：
Marshall, SJ
中科院分区：
文献类型：
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作者：
Marshall, GW;Balooch, M;Marshall, SJ
牙本质釉质连接（DEJ）是一种复杂且不明确的结构，其将脆性的上覆釉质与形成牙齿主体的牙本质结合在一起。此外，这种结构似乎为牙齿赋予了优异的韧性和裂纹偏转性能，并且作为结合不同材料的结构的仿生模型引起了人们的极大兴趣。这项工作试图使用基于纳米压痕的改性AFM来确定纳米硬度和弹性模量，以表征DEJ区域中的纳米力学性能。在三个第三磨牙的抛光矢状面上，沿沿着三个方向从牙本质到釉质以1-2 μ m的间隔制作横穿DEJ的压痕线。纳米硬度和弹性模量稳步上升整个DEJ从散装牙本质到釉质。DEJ宽度估计局部多项式回归拟合每个样品和位置的机械性能曲线的数据梯度从牙釉质到牙本质，并给出了一个平均值为11.8妈妈，这并没有显着变化与牙内位置或牙齿之间。纳米压痕也被用来启动裂纹的DEJ区域。与先前的工作一致，很难引发穿过DEJ的裂纹，或者在牙本质中产生裂纹。牙釉质的断裂韧性值为0.6-0.9 MPa.m（1/2），与最近的显微压痕断裂结果吻合良好。我们的研究结果表明，DEJ显示梯度结构和nanoindenation方法显示出进一步了解其结构和功能的希望。(C)John Wiley & Sons，Inc.
The dentinoenamel junction (DEJ) is a complex and poorly defined structure that unites the brittle overlying enamel with the dentin that forms the bulk of the tooth. In addition, this structure appears to confer excellent toughness and crack deflecting properties to the tooth, and has drawn considerable interest as a biomimetic model of a structure uniting dissimilar materials. This work sought to characterize the nanomechanical properties in the region of the DEJ using modified AFM based nanoindentation to determine nanohardness and elastic modulus. Lines of indentations traversing the DEJ were made at 1-2 mum intervals from the dentin to enamel along three directions on polished sagittal sections from three third molars. Nanohardness and elastic modulus rose steadily across the DEJ from bulk dentin to enamel. DEJ width was estimated by local polynomial regression fits for each sample and location of the mechanical property curves for the data gradient from enamel to dentin, and gave a mean value of 11.8 mum, which did not vary significantly with intratooth location or among teeth. Nanoindentation was also used to initiate cracks in the DEJ region. In agreement with prior work, it was difficult to initiate cracks that traversed the DEJ, or to produce cracks in the dentin. The fracture toughness values for enamel of 0.6-0.9 MPa.m(1/2) were in good agreement with recent microindentation fracture results. Our results suggest that the DEJ displays a gradient in structure and that nanoindenation methods show promise for further understanding its structure and function. (C) 2000 John Wiley & Sons, Inc.