1995 Fiscal Year Final Research Report Summary

Do carious phenomenon affect on the lifetime of artificial root made of apatite.

Research Project

Project/Area Number	06671977
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	補綴理工系歯学
Research Institution	ASAHI UNIVERSITY
Principal Investigator	WAKAMATSU Nobukazu Asahi University, Department of Dental Materials and Technology, Assistant, 歯学部, 助手 (00158594)
Project Period (FY)	1994 – 1995
Keywords	Apatite / Fracture mechanics / Fatigue / Artificial bone
Research Abstract	The post-indentation method with a small specimen was to be a successful one to measure the fatigue parameter of the hydroxyapatite (HAP) polycrystals as a function of pH of acidic solutions, and to measure the crack extension behavior of a micro-cracks, which length was similar to that of fracture origin in ceramics. Although the measured fatigue parameter had dependence on the indent load, the value of the parameter was similar to those reported previously. The minimum of the stress intensity factor, K_<Ith>, was also measured by using the post-indentation method. The value of K_<Ith> ranged from 20% to 30% of the fracture toughness of the HAP ceramics. The hot-pressing was shown to be a successful method to obtain pore-free 70wt%HAP-30wt%poly-lactic acid (PLA) composites with the bulk density similar to that of bone. For the composites of HAP2 with 30wt%PLA,it was possible to align the HAP crystals perpendicular to the loading direction, and hence, to make the composites having the anisotropic microstructure.