Ultrastructure and nanomechanical properties of cementum dentin junction
Ultrastructure and nanomechanical properties of cementum dentin junction
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DOI：
10.1002/jbm.a.20061
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发表时间：
2004-02-01
影响因子：
4.9
通讯作者：
Marshall, SJ
中科院分区：
文献类型：
--
作者：
Ho, SP;Balooch, M;Marshall, SJ
牙骨质和牙本质之间的附着已经给出了几种定义和命名，包括：带间层、中间牙骨质、胶原裂孔、Hopewell-Smith透明层，以及更常见的牙骨质-牙本质连接（CDJ）。了解两个结构不同的硬组织，如牙骨质和牙本质的连接定义，可以提供必要的信息，工程功能梯度材料，可用于有效的牙齿矫正在临床牙科和其他生物工程应用。因此，在这项研究中，作为使用生物力学方法理解CDJ的第一步，假设牙骨质和牙本质之间的CDJ是一个宽区域，其机械性能显著低于邻近组织。的CDJ的结构进行了研究，使用原子力显微镜（AFM），和网站特定的机械响应的三个区域，牙骨质，CDJ，和牙本质使用AFM纳米压头在干燥和潮湿的条件下进行了测定。CDJ的AFM结果表明，在干燥条件下有一个谷，在潮湿条件下有一个峰。谷的深度的大小与CDJ的峰的高度大致相同，范围从10到40 μ m。在干燥条件下的纳米力学性质表明，CDJ（E-r = 17.5 +/- 2.7 GPa，H = 0.6 +/- 0.1 GPa）和牙骨质（E-r = 18.7 +/- 2.5 GPa，H = 0.6 +/- 0.1 GPa）的弹性模量和硬度没有显著差异（p > 0.05）。在干燥条件下，CDJ的机械性能显著低于（p < 0.05）牙本质（E-r = 19.9 +/- 2.9 GPa，H = 0.6 +/- 0.1 GPa）。然而，在更相关的水化条件下，CDJ的力学性能（E，3.0 +/- 0.7 GPa，H = 0.1 +/- 0.0 GPa）显著降低（p <0.05），牙骨质（E-r6. 8 +/-1.9GPa，H = 0.2 +/-0.1GPa）和牙本质（E-r9. 4 +/-2.3GPa，H = 0.3 +/-0.1GPa）。根据本研究的结果，可以得出结论，与邻近的硬组织、牙骨质和牙本质相比，CDJ可以被视为含有大量蛋白质（包括胶原蛋白）的宽区域，这些蛋白质有助于水合作用并显著降低机械性能。CDJ较低的力学性能可能使其能够将咬合载荷重新分配到牙槽骨。(C)2003 Wiley Periodicals，Inc.
The attachment between cementum and dentin has been given several definitions and nomenclature, including: interzonal layer, intermediate cementum, collagen hiatus, Hopewell-Smith's hyaline layer, and more commonly, cementum-dentin junction (CDJ). Understanding the attachment of two structurally dissimilar hard tissues such as cementurn and dentin defined by a junction may provide information necessary to engineer functionally graded materials that can be used for efficient tooth restorations in clinical dentistry and other bioengineering applications. Hence, in this study, as a first step toward understanding the CDJ using a biomechanical approach, it was hypothesized that the CDJ between cementurn and dentin is a wide zone with mechanical properties significantly lower than the neighboring tissues. The structure of the CDJ was studied using an atomic force microscope (AFM), and site-specific mechanical response of the three regions; cementurn, CDJ, and dentin were determined using an AFM-nanoindenter under dry and wet conditions. The AFM results of the CDJ demonstrated a valley under dry conditions and a peak under wet conditions. The magnitude of the depth of the valley was approximately the same as the height of the peak of the CDJ, ranging from 10 to 40 mum. The nanomechanical properties under dry conditions indicated no significant difference (p > 0.05) in elastic modulus and hardness of the CDJ (E-r = 17.5 +/- 2.7 GPa, H = 0.6 +/- 0.1 GPa) and cementum (E-r = 18.7 +/- 2.5 GPa, H = 0.6 +/- 0.1 GPa). The mechanical properties of the CDJ were significantly lower (p < 0.05) than dentin (E-r = 19.9 +/- 2.9 GPa, H = 0.6 +/- 0.1 GPa) under dry conditions. However, under more relevant hydrated conditions, the mechanical properties of CDJ (E, 3.0 +/- 0.7 GPa, H = 0.1 +/- 0.0 GPa) were significantly lower (p much less than 0.05) than those of cementurn (E-r 6.8 +/- 1.9 GPa, H = 0.2 +/- 0.1 GPa) and dentin (E-r 9.4 +/- 2.3 GPa, H = 0.3 +/- 0.1 GPa). Based on the results from this study, it can be concluded that the CDJ can be regarded as a wide zone containing large quantities of proteins including collagen that contribute to hydration and significantly reduce mechanical properties, compared with the adjacent hard tissues, cementurn, and dentin. The lower mechanical properties of the CDJ may make it possible for it to redistribute occlusal loads to the alveolar bone. (C) 2003 Wiley Periodicals, Inc.