1990 Fiscal Year Final Research Report Summary
Fundamental Study of Bioactivity of Inorganic Materials
| Project/Area Number |
01430014
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学
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| Research Institution | Kyoto University |
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Principal Investigator |
KOKUBO Tadashi Kyoto University, Institute for Chemical Research, Professor, 化学研究所, 教授 (30027049)
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| Co-Investigator(Kenkyū-buntansha) |
KIYAMA Masao Kyoto University, Institute for Chemical Research, Associate Professor, 化学研究所, 助教授 (10027047)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Ceramics / Glass / Glass-Ceramics / Bioactivity / Apatite / CaO-SiO_2-P_2O_5 / CaO-SiO_2-Al_2O_3 / Artificial Bone |
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| Research Abstract |
A few kind of inorganic materials spontaneously bond to living bone. They are called bioactive materials and already clinically used as some bone substitutes. Their bone-bonding mechanism is not, however, fully understood. In the present study, factors governing the bioactivity was studied. It was confirmed by in vitro as well as in vivo experiments that Ceravital^<<0!>>-type apatite-containing glass-ceramic also bond to living bone through a Ca, P-rich layer which is formed on its surface in the body, similar to Bioglass and glass-ceramic A-W. It was shown by X-ray microdiffraction that the Ca, P-rich layer formed at the interface between glass-ceramic A-W and the bone of a sheep is indeed an apatite layer as expected from in vitro experiments. Analysis of surface reaction of glass-ceramic A-W in a simulated body fluid showed that the apatite layer on the surface of the glass-ceramic is formed by a nucleation of the apatite which is induced by the reaction of Ca (II) and Si (IV) ions dissolved from the glass-ceramics with P (V) ion in the fluid, and growth of the apatite which is achieved by consuming Ca (II) and P (V) ions from the fluid. Analysis of surface reaction of CaO-SiO_2-P_2O_5 and CaO-SiO_2-Al_2O_3 glasses in a simulated body fluid showed that apatite formation on the surfaces of glasses is restricted to CaO, SiO_2-based compositional region, because the Ca (II) and Si (IV) ions dissolved from glasses play cooperative important role in forming the surface apatite. The Ca (II) ion increases the degree of the supersaturation of the surrounding fluid with respect to the apatite, whereas the Si (IV) ion induces apatite nucleation.
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