2005 Fiscal Year Final Research Report Summary
Development and establishment of high performance functional monomers
| Project/Area Number |
16591914
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SHIRAI Kenichi Hiroshima University, Graduate School of Biomedical Sciences, research Associate, 大学院・医歯薬学総合研究科, 助手 (20325179)
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| Co-Investigator(Kenkyū-buntansha) |
ARAKAWA Makoto Hiroshima University, Hospital, research Associate, 病院・助手 (60379881)
YOSHIDA Yasuhiroi Okayama University, Graduate School of Biomaterials, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (90281162)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Functional monomer / Adhesion / XPS / TEM |
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| Research Abstract |
Mild self-etch adhesives only partially demineralize dentin, leaving hydroxyapatite around collagen within a submicron hybrid layer. This residual hydroxyapatite may serve as receptor for chemical interaction with the functional monomer and subsequently contribute to adhesive performance in addition to micro-mechanical hybridization. We therefore characterized the adhesive interaction of three functional monomers chemically with synthetic hydroxyapatite using X-ray Photoelectron Spectroscopy and Atomic Absorption Spectrophotometry, and ultra-morphologically with dentin using Transmission Electron Microscopy.
1.Comparing chemical bonding efficacy of the three functional monomers investigated, quantitative determination of carbon concentration on hydroxyapatite revealed that the bonding potential of 10-MDP to hydroxyapatite is significantly stronger than that of 4-MET, even after 30-min exposure. Moreover, the fact that even a short 30-s exposure of hydroxyapatite to 10-MDP produced a significant C 1s peak and that the peak intensity increased no further by extending the exposure time, strongly suggests that 10-MDP has a high chemical bonding potential to hydroxyapatite within a clinically reasonable application time.
2.TEM revealed that all three self-etch adhesives formed a shallow (0.5-1μm) hybrid layer. Unstained, non-demineralized sections revealed that all systems demineralized dentin only partially, leaving hydroxyapatite around collagen within the submicron hybrid layer. Staining disclosed a typical hybrid-layer ultra-structure with cross-banded collagen separated by electron lucent interfibrillar spaces. A typical ‘shag-carpet' often appeared at the hybrid-layer top. Stained, demineralized sections confirmed the acid-resistance of the hybrid layer.
3.The calcium salt of 10-MDP (10-MDPCa) was significantly the least soluble in water
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