Department of Functional Anatomy, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, Room 12N13, 1081 LA, Amsterdam, The Netherlands.
J Biomech. 2011 Feb 3;44(3):402-7. doi: 10.1016/j.jbiomech.2010.10.004. Epub 2010 Oct 30.
Knowledge of the influence of mineral variations (i.e., mineral heterogeneity) on biomechanical bone behavior at the trabecular level is limited. The aim of this study is to investigate how this material property affects the intratrabecular distributions of stress and strain in human adult trabecular bone. Two different sets of finite element (FE) models of trabecular samples were constructed; tissue stiffness was either scaled to the local degree of mineralization of bone as measured with microCT (heterogeneous) or tissue stiffness was assumed to be homogeneous. The influence of intratrabecular mineral heterogeneity was analyzed by comparing both models. Interesting effects were seen regarding intratrabecular stress and strain distributions. In the homogeneous model, the highest stresses were found at the surface with a significant decrease towards the core. Higher superficial stresses could indicate a higher predicted fracture risk in the trabeculae. In the heterogeneous model this pattern was different. A significant increase in stress with increasing distance from the trabecular surface was found followed by a significant decrease towards the core. This suggests trabecular bending during a compression. In both models a decrease in strain values from surface to core was predicted, which is consistent with trabecular bending. When mineral heterogeneity was taken into account, the predicted intratrabecular patterns of stress and strain are more consistent with the expected biomechanical behavior as based on mineral variations in trabeculae. Our findings indicate that mineral heterogeneity should not be neglected when performing biomechanical studies on topics such as the (long-term or dose dependent) effects of antiresorptive treatments.
对矿物质变化（即矿物质异质性）对小梁水平骨生物力学行为的影响知之甚少。本研究旨在探讨这种材料特性如何影响成人松质骨小梁内的应力和应变分布。构建了两组不同的小梁样本有限元（FE）模型；组织刚度要么按微 CT 测量的骨局部矿化程度进行缩放（异质），要么假设组织刚度是均匀的。通过比较这两种模型来分析骨内矿物质异质性的影响。关于骨内的应力和应变分布，观察到了有趣的效果。在均匀模型中，表面的应力最高，向核心显著降低。较高的表面应力可能表明小梁的预测骨折风险较高。在非均匀模型中，这种模式不同。发现随着距离小梁表面的增加，应力显著增加，然后向核心显著降低。这表明小梁在压缩过程中发生弯曲。在这两种模型中，从表面到核心的应变值均预测下降，这与小梁弯曲一致。当考虑矿物质异质性时，预测的小梁内应力和应变模式与基于小梁矿物质变化的预期生物力学行为更为一致。我们的研究结果表明，在进行抗吸收治疗的（长期或剂量依赖性）效果等生物力学研究时，不应忽视矿物质异质性。
