X線回折による再石灰化骨の力学挙動計測

抄録

The demand of artificial bones as substitutes of natural bone for producing bone grafts is increasing and the ways to recalcify collagen are examined. One of the methods to do so is called PILP process. This mothed is different from previous ones and it was reported that this method could imitate the structure of natural bone. Previous researches have investigated ultra-scale bone structures by SEM, TEM and so on, but only few mechanical tests were conducted. The purpose of this study is to examine mechanical behaviors of recalcified bone through PILP process, by tensile test and X-ray diffraction. Specimens were cut from the cortical bone of the lateral aspect of the middle diaphysis of an adult right bovine femur. Specimens were fully decalcified by 10 % formic acid and then recalcified by recalcification solution. There were 4 conditions of specimens, intact specimens, decalcified specimens, 5 days recalcified specimen and 7 days recalcified specimen. The elastic modulus was determined by tensile test under optical microscope. The microscopic strain of HAp crystal was measured by X-ray diffraction. The elastic moduli of recalcified specimen were much lower than intact specimen. The reasons why that were thought to be that the time to recalcify specimens was too short and anisotropy of 7 days recalcified specimen decreased. The relationship between tissue strain and microscopic strain of HAp crystal at (211) crystal plane in intact specimen was positive. The relationship in recalcified specimen was a slightly positive. In recalcified specimens, because the amount of HAp crystals was small and the stress was concentrated on collagen, the lattice strain was small and correlation became weak. As the recalcification progressed, the anisotropy characteristic became decreased when comparing to natural bone. But, the mechanical behavior of recalcified specimen is similar to natural bone.