2004 Fiscal Year Final Research Report Summary
Development of new endodontic materials by changing microstructure of hydroxyapatite ceramics
| Project/Area Number |
14370619
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Conservative dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
KINOMOTO Yoshifumi Osaka University, Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (10252694)
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| Co-Investigator(Kenkyū-buntansha) |
IMAZATO Satoshi Osaka University, Graduate School of Dentistry, Associate Professor, 大学院・歯学研究科, 助教授 (80243244)
NAKANO Takayoshi Osaka University, Graduate School of Dentistry, Associate Professor, 大学院・工学研究科, 助教授 (30243182)
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| Project Period (FY) |
2002 – 2004
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| Keywords | hydroxyapatite / soluble calcium phosphate / solubility / endodontics / tissue engineering / α-TCP / tetracalcium phosphate / osteoblast |
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| Research Abstract |
Hydroxyapatite(HAp) and the related calcium phosphates have been of great interest as biological materials for regenerating hard tissues, but their solubility should be improved to fit the remolding cycle of hard tissues in vivo before their practical use for bone grafts. In this study, surface and boundary layers of HAp were modified by annealing at 1350℃ in a vacuum to produce calcium phosphate phases with high solubility, and HAp/soluble calcium phosphate(HAp/SCaP) composites were formed. The soluble surface and boundary layers were composed of tetracalcium phosphate(TetCP), α-tricalcium phosphate (α-TCP) and amorphous calcium oxide(CaO). Effects of TetCP and α-TCP on MC3T3-E1 proliferation, differentiation, and mineralization were examined by tissue culture system. Culture in the presence of TetCP or α-TCP showed no significant influence on cell proliferation. The alkaline phosphatase activities of the cells were enhanced by both calcium phosphates for 3 days and the expression of type I collagen was promoted at 12 hours and 1 day after incubation. Enhancement of bone-like tissue formation by the addition of TetCP or α-TCP at 10 μM was observed after 7 days incubation and thereafter. Significantly greater cells attachment were observed to HAp/SCaP composites annealed for 10 hours than those annealed for 1 hour or HAp. For examining the tissue responses to HAp/SCaP composites, incisors of beagle dogs were extracted, and the specimens were inserted into the sockets. Histopathological evaluation after 1 and 3 months demonstrated that bone regeneration was found on the surface and in the space after the dissolution of soluble components for HAp/SCaP composites, although HAp resulted in bone formation only along the material surface. In conclusion, HAp/SCaP composites were found to be promising biological materials for regenerating hard tissues.
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