Nanoindentation mapping of the mechanical properties of human molar tooth enamel
Nanoindentation mapping of the mechanical properties of human molar tooth enamel
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DOI：
10.1016/s0003-9969(02)00006-7
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发表时间：
2002-04-01
影响因子：
3
通讯作者：
Weihs, TP
中科院分区：
文献类型：
--
作者：
Cuy, JL;Mann, AB;Weihs, TP
牙釉质的力学行为一直是许多研究的主题。最初的研究假设它是一种或多或少均匀的材料，具有均匀的机械性能。现在人们普遍认识到，釉质的机械响应取决于位置，化学成分和棱柱取向。本研究利用奈米压痕技术，以一颗上颌骨第二臼齿（M-2）之牙釉质为研究对象，探讨其轴向剖面上之牙釉质性质。机械特性的局部变化与样品的整个深度和跨度上的化学含量和微观结构的变化相关。微探针技术被用来检查化学成分的变化和扫描电子显微镜被用来检查微观结构。在单个牙齿上观察到的硬度（H）和杨氏模量（E）的范围远大于先前报道的范围。在釉质表面H > 6 GPa，E > 115 GPa，而在釉质-牙本质交界处H <3GPa，E < 70 GPa。这些变化对应于化学，微观结构和棱镜排列的变化，但与釉质的平均化学变化的相关性最强。例如，羟基磷灰石（P2 O 5和CaO）的成分的浓度是最高的硬咬合面，并在移动到较软的釉质牙本质交界处下降。Na_2O和MgO则表现出相反的趋势。釉质的机械性能也被发现不同的舌颊侧的磨牙。在咬合面上，舌侧的釉质比颊侧的釉质更硬、更硬。然而，内部釉质在舌侧比在颊侧更柔软且更柔顺，这种变化也与平均化学差异相关，并且可能与功能差异有关。(C)2002爱思唯尔科技有限公司版权所有。
The mechanical behavior of dental enamel has been the subject of many investigations. Initial studies assumed that it was a more or less homogeneous material with uniform mechanical properties. Now it is generally recognized that the mechanical response of enamel depends upon location, chemical composition, and prism orientation. This study used nanoindentation to map out the properties of dental enamel over the axial cross-section of a maxillary second molar (M-2). Local variations in mechanical characteristics were correlated with changes in chemical content and microstructure across the entire depth and span of a sample. Microprobe techniques were used to examine changes in chemical composition and scanning electron microscopy was used to examine the microstructure. The range of hardness (H) and Young's modulus (E) observed over an individual tooth was found to be far greater than previously reported. At the enamel surface H > 6 GPa and E > 115 GPa, while at the enamel-dentine junction H < 3 GPa and E < 70 GPa. These variations corresponded to the changes in chemistry, microstructure, and prism alignment but showed the strongest correlations with changes in the average chemistry of enamel. For example, the concentrations of the constituents of hydroxyapatite (P2O5 and CaO) were highest at the hard occlusal surface and decreased on moving toward the softer enamel-dentine junction. Na2O and MgO showed the opposite trend. The mechanical properties of the enamel were also found to differ from the lingual to the buccal side of the molar. At the occlusal surface the enamel was harder and stiffer on the lingual side than on the buccal side. The interior enamel, however, was softer and more compliant on the lingual than on the buccal side, a variation that also correlated with differences in average chemistry and might be related to differences in function. (C) 2002 Elsevier Science Ltd. All rights reserved.