| Project/Area Number |
17591981
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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 | Hokkaido University |
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Principal Investigator |
NAKAOKI Yasuko Hokkaido University, Graduate School of Dental Medicine, Assistant Professor (50302881)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Hidehiko Hokkaido University, Graduate School of Dental Medicine, Professor (90205998)
INOUE Satoshi Hokkaido University, Hokkaido University Hospital, Lecturer (80184745)
NODA Mamoru Hokkaido University, Hokkaido University Hospital, Lecturer (10301889)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥300,000)
Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | dentin / adhesive interface / long-term durability / SEM observation / 経時的変化 / TEM観察 |
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| Research Abstract |
Tb evaluate the degradation of exposed collagen fibril of resin -dentin adhesive interface with MMP, the micro-tensile bond tests and the observation of the interface of adhesive samples was carried out.
The specimens, which bonded to moist-dentin and immersed in MMP for six months, exhibited lower bond strength than the specimens immersed for one day. The specimens bonded with pressure from the pulp chamber showed significant reduction in bond strength between one day and six months. 1b the contrary, the bond strengths of specimens bonded to dried dentin did not vary In the SEM images of fractured surfaces after tensile test, longer exposure of fibrils are observed in six months specimens than one day specimens than one day specimens in some adhesives. Especially, on the specimens with pressure from the pulp side, the alterations of length of exposed collagen fibrils are very obvious after six month. In dried specimens, the similar trend was observed as moist specimens groups. In the image of TEM, the tiny voids were observed in resin-dentin interface and it was speculated that these voids affect to the alteration of resin-dentin interface over time.
On the other hand, the reduction of MAP attack to the exposure of collagen fibrils may prevent the degradation of resin-dentin interface. The double coating of bonding resin increase the rate of polymerization and stiff polymerized resin would protect the collagen fibrils. The exposure of collagen fibrils decrease and the rate of degradation with MW will be slower. The results of some adhesives bonded with sound dentin showed increase of bond strength with double coating. From now on, the degradation of adhesive interface bonded with double- coated method must be detected over time.
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