1991 Fiscal Year Final Research Report Summary
Development of Toughened Porous Hydroxyapatite Sintered Body for Artificial Bone
| Project/Area Number |
01570848
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Kitasato University |
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Principal Investigator |
MATSUNO T. Kitasato University, School of Medicine, Associate Professor, 医学部, 助教授 (80104537)
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| Co-Investigator(Kenkyū-buntansha) |
SAKURAI K. Kitasato University, School of medicine, Assistant Professor, 医学部, 講師 (60050506)
KOISHI M. Science University of Tokyo, Faculty of Industrial Science and Technology, Profe, 基礎工学部, 教授 (70084423)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Hydroxyapatite / Sintered Body / Porous Sintered Body / Fracture Toughness / Artificial Bone |
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| Research Abstract |
1. The fine rod-like hydroxyapatite(HAP) crystals and spherical HAP particles were prepared with calcium nitrate tetrahydrate and diammonium hydrogenphosphate by the semibatchwise homogeneous reaction. The spherical particle's were obtained by addition of sodium citrate(1x10^<-3> mol/l) to the reaction system.
2. An investigation was undertaken to determine the effect of various conditions on preparation of HAP spherulite in agar-agar gel. It was revealed that the existence of small amounts of additives promote the formation of spherical HAP or amorphous calcium phosphate particles. The more detailed studies will be carried out for obtaining information on the mechanism of the spherical particle formation.
3. Chemical changes of HAP to other calcium phosphate compounds by the calcination and(or) the sintering process were investigated. In the case of Ca/P molar ratio of HAP was close to the theoretical value of 1.67, no change was occurred even when it was heated at 1000-1200ﾟC for 3 hou
… More
rs. In other cases (Ca/P molar ratio<1.67), it was recognized that HAP was changed to P-calcium phosphate by heating operation.
4. The interesting information, regarding the change of particle size distribution was obtained from a study of the calcination process of the precipitated HAP. The width of the distribution decreased witb decreasing calcination temperatures.
5. Internal homogeneity of the green compact body and the sintered body of HAP was widely studied by a CT-scanner. The sintered body was somewhat more heterogeneous than the corresponding green compact body.
6. The HAP sintered bodies having relative density of 49.4-85.5% were obtained by the compression molding and the heating operation of the particles with varying microstructures. Fracture toughness of these porous HAP sinipied bodi-es was evaluated by a SEVNB method. The values were 0.13-0.76 MPam^<1/2>. A linear relation between the relative density and fracture toughness was recognized ; the fracture toughness increased with an increase of the relative density. Less
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