Bone and Joint Research Laboratory, Surgical Pathology, SA Pathology, Adelaide, Australia.
J Biomech. 2010 Dec 1;43(16):3144-9. doi: 10.1016/j.jbiomech.2010.07.038. Epub 2010 Aug 17.
In trabecular bone, each remodeling event results in the resorption and/or formation of discrete structural units called 'packets'. These remodeling packets represent a fundamental level of bone's structural hierarchy at which to investigate composition and mechanical behaviors. The objective of this study was to apply the complementary techniques of quantitative backscattered electron microscopy (qBSEM) and nanoindentation to investigate inter-relationships between packet mineralization, elastic modulus, contact hardness and plastic deformation resistance. Indentation arrays were performed across nine trabecular spicules from 3 human donors; these spicules were then imaged using qBSEM, and discretized into their composite remodeling packets (127 in total). Packets were classified spatially as peripheral or central, and mean contact hardness, plastic deformation resistance, elastic modulus and calcium content calculated for each. Inter-relationships between measured parameters were analysed using linear regression analyses, and dependence on location assessed using Student's t-tests. Significant positive correlations were found between all mechanical parameters and calcium content. Elastic modulus and contact hardness were significantly correlated, however elastic modulus and plastic deformation resistance were not. Calcium content, contact hardness and elastic modulus were all significantly higher for central packets than for peripheral, confirming that packet mineral content contributes to micromechanical heterogeneity within individual trabecular spicules. Plastic deformation resistance, however, showed no such regional dependence, indicating that the plastic deformation properties in particular, are determined not only by mineral content, but also by the organic matrix and interactions between these two components.
在小梁骨中,每个重塑事件都会导致离散结构单元的吸收和/或形成,这些结构单元称为“包”。这些重塑包代表了骨骼结构层次的基本水平,可以研究其组成和力学行为。本研究的目的是应用定量背散射电子显微镜(qBSEM)和纳米压痕技术来研究矿化、弹性模量、接触硬度和塑性变形阻力之间的相互关系。在来自 3 位供体的 9 个小梁刺中进行了压痕阵列;然后使用 qBSEM 对这些小梁刺进行成像,并将其离散化为复合重塑包(总共 127 个)。根据空间位置将包分类为周边或中央,并计算每个包的平均接触硬度、塑性变形阻力、弹性模量和钙含量。使用线性回归分析研究测量参数之间的相互关系,并使用学生 t 检验评估位置依赖性。发现所有力学参数与钙含量之间均存在显著正相关。弹性模量和接触硬度显著相关,但弹性模量和塑性变形阻力不相关。中央包的钙含量、接触硬度和弹性模量均显著高于周边包,这证实了包矿含量有助于单个小梁刺的微观力学异质性。然而,塑性变形阻力没有表现出这种区域依赖性,这表明塑性变形性能不仅取决于矿物质含量,还取决于有机基质以及这两个成分之间的相互作用。