| Project/Area Number |
08457503
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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 | Tokyo Medical and Dental University |
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Principal Investigator |
NAKABAYASHI Nobuo Tokyo Medical and Dental University, Institutefor Medical and Dental Engineering, Professor, 医用器材研究所, 教授 (30014020)
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| Co-Investigator(Kenkyū-buntansha) |
IWASAKI Yasuhiko Tokyo Medical and Dental University, Institutefor Medical and Dental Engineering, 医用器材研究所, 助教授 (90280990)
WATANABE Akihko Tokyo Medical and Dental University, Institutefor Medical and Dental Engineering, 医用器材研究所, 助手 (30126263)
ISHIHARA Kazuhiko The University of Tokyo, Department of Materials Science Graduate School of Engi, 大学院・工学系研究科, 助教授 (90193341)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1996: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Dental Materials / adhesive resin cements / Dentin / Tensile Test / Hybridized Dentin / Dumbbell-Shaped specimens / Adhesion / Medical Materials / 接着性レジン |
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| Research Abstract |
A reliable method for bonding resin to dentin was proposed. The procedure described hybridization of dentin substrates by impregnation and polymerization of adhesive monomers therein, creating a 'hybridized dentin' or 'hybrid layer. Often, applied adhesive monomers do not fully penetrate the acid-conditioned substrate, and a zone of demineralized dentin that is not resin-impregnated is left sandwiched between the hybridized dentin and the unaltered underlying mineralized dentin. An unfilled zone of the demineralized dentin causes defects in bonded dentin. It was very difficult to examine the presence of the defect at the base of the hybrid layer was not understood when the amount of [strength of unfilled zone] x [the area] was larger than the resin or bond strength. Thus, the results of conventional tensile bond strength measurement have often been misinterpreted. The defects in the bonded dentin were investigated by soaking the specimens in water to decrease the strength of collagen b
… More
y the hydrolysis. However, it takes a long time to ascertain whether the dentin bond is excellent or not. These results persuaded us to develop a method to measure tensile bond strength on specimens which have the same cross-section at the bonded area. Dumbbell-shaped dentin bonded specimens must be a good candidate as dumbbell specimens are generally used to measure tensile strength of materials.
It was reported that the defects in bonded bovine dentin were formed when the dentin was treated with an aqueous solution of 10% citric acid/3% ferric chloride for 10 sec. The defects were observed in using dumbbell specimens, but not in conversional specimens.
It was also clear that defective dentin bond is not so good even when cohesive failure in resin was observed by the conventional test. When adhesive monomers more fully impregnated the entire region of demineralized dentin, the quality of the dentin bond was excellent. We will continue to develop such bonding systems to provide stable adhesion without defects by using dumbbell specimens. Less
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