Effect of Gradual Demineralization on the Mineral Fraction and Mechanical Properties of Cortical Bone
Effect of Gradual Demineralization on the Mineral Fraction and Mechanical Properties of Cortical Bone
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DOI：
10.1299/jbse.4.230
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发表时间：
2009
影响因子：
--
通讯作者：
M. Todoh;S. Tadano;B. Giri;M. Nishimoto
中科院分区：
文献类型：
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作者：
M. Todoh;S. Tadano;B. Giri;M. Nishimoto
骨通常被认为是由羟基磷灰石（HAp-like）矿物颗粒、有机基质（主要是I型胶原）和水相组成的复合材料。骨在宏观尺度上的力学性能取决于微观尺度上的结构组织和成分性质。为了了解微观成分对骨力学性能的影响，研究了完整或完全脱矿样品的力学性能与矿物质含量之间的关系。即使是矿物含量的轻微改变也会对机械性能产生重大影响。在这项工作中，脱矿程度对牛皮质骨的机械性能的影响，通过逐渐去除矿物质含量和测量成分，在每一个步骤，直到几乎没有微量的矿物质观察。将标本在10% EDTA二钠溶液中脱矿12、24、48、72小时和14天。根据其X射线吸收特性和定量透射X射线强度计算脱矿样品中各结构组分的体积分数。进行拉伸试验以测量脱矿质试样的弹性模量和极限强度。这项工作表明，弹性模量和极限强度的皮质骨的矿物含量作为微观成分的强烈依赖性。与矿物质损失的依赖程度已被证明是精确的，以提供矿物质含量的重要性及其对骨的机械功能的作用。
Bone is often regarded as a composite material consisting of hydroxyapatite (HAp-like) mineral particles, organic matrix (mostly Type I collagen) and water phases in microscopic scale. The mechanical properties of bone at macroscopic scale depend on the structural organization and properties of constituents in the microscopic scale. In the attempts of understanding the effect of microscopic constituent on the mechanical properties of bone, the relationship between mechanical properties and mineral content of intact or completely demineralized samples have been studied. Even a slight alteration in the mineral content would have significant effect on the mechanical properties. In this work, the effect of degree of demineralization to the mechanical properties of bovine cortical bone was examined by gradually removing the mineral content and measuring constituents at every step till almost no traces of minerals were observed. Specimens were demineralized in 10% disodium EDTA solutions for 12, 24, 48, 72 hours and 14 days. The volume fraction of each structural constituent in the demineralized specimens was calculated from their X-ray absorption characteristics and quantifying transmitted X-ray intensity. Tensile tests were performed to measure the elastic modulus and ultimate strength of the demineralized specimens. This work shows the strong dependence of elastic modulus and ultimate strength of cortical bone to the mineral content as microscopic constituent. The degree of dependence with mineral loss has been demonstrated precisely so to provide the importance of mineral content and its role on the mechanical functioning of bone.