Preferential orientation of biological apatite crystallite in original,regenerated and diseased cortical bones

摘要

The bone mechanical function depends on both bone quantity and quality corresponding dominantly to bone mineral density(BMD:density of biological apatite)and other factors,respectively.BMD is correlated with bone strength but accounts for only 60-70% of the variance in the ultimate strength of bone tissue.Thus,new parameters representing bone quality have been investigated so far.Bone has a well-organized microstructure on the nano-scale level and is composed of mineral biological apatite(BAp)and collagen(Col)fibril,providing reinforcement and pliability,respectively.Because BAp crystallizes in an anisotropic hexagonal lattice,mechanical properties of a BAp crystallite should depend on the crystal orientation.Thus,preferential orientation of the BAp c-axis along the extended collagen fibrils in hard tissues must be closely related to the mechanical function of bone and is also utilized as a possible index for evaluating bone quality.In this study,BAp orientation was analyzed as a parameter of bone quality in hard tissues under various conditions such as original,regenerated and diseased bones.Finally,we can conclude that the degree of BAp orientation is a useful parameter to evaluate in vivo stress distribution,nano-scale microstructure and the related mechanical function,the regenerative process of the regenerated bone and to diagnose bone diseases such as osteoarthritis,etc.