Evaluation of mechanical property by preferential alignment of biological apatite in human mandible

生物磷灰石（BAp）晶体c轴排列被认为是骨力学功能的一个因素。本研究旨在阐明人类下颌骨皮质骨牙槽区和下颌骨基底区BAp晶体排列与杨氏模量的关系。微束x射线衍射系统用于测定BAp晶体沿中远端方向（纵轴）的排列。用纳米压痕法测量了相同位置的中远端杨氏模量，并研究了BAp晶体排列与杨氏模量的关系。本研究表明BAp晶体排列与杨氏模量之间存在密切关系，表明在评估骨强度时确定BAp晶体排列的重要性。测定人类下颌骨第一磨牙的BAp晶体排列也可用于检查咬合力的影响。

Biological apatite (BAp) crystallite c-axis alignment is known to be a factor in the mechanical function of bone. This study aimed to elucidate the relationship between BAp crystallite alignment and Young's modulus in the alveolar area and base of the mandible area in human mandible cortical bone. A microbeam X-ray diffraction system was used to determine BAp crystallite alignment along the mesiodistal direction (longitudinal axis). Young's modulus along the mesiodistal direction in the same sites was also measured with nanoindentation, and the relationship between BAp crystallite alignment and Young's modulus was examined.The present study suggests a close relationship between BAp crystallite alignment and Young's modulus, suggesting the importance of determining BAp crystallite alignment when evaluating bone strength. Determination of BAp crystallite alignment at first molar in the human mandible may also be useful in examining the effects of occlusal force.