| Project/Area Number |
61480405
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
補綴理工系歯学
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| Research Institution | Kyoto University |
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Principal Investigator |
TANI Yoshiaki Research Center For Medical Polymers and Biomaterials, Kyoto University, 医用高分子研究センター, 助教授 (90026881)
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| Co-Investigator(Kenkyū-buntansha) |
TOGAYA Toshihiro Research Center for Medical Polymers and Biomaterials, Kyoto University, 医用高分子研究センター, 助手 (50127106)
TSUTSUMI Sadami Research Center for Medical Polymers and Biomaterials, Kyoto University, 医用高分子研究センター, 助手 (00028739)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1987: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥4,600,000 (Direct Cost: ¥4,600,000)
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| Keywords | Dentin-pretreatment / Adhesion to tooth / Composite resin / Smear layer / 歯質表面処理 / コンポジットレジン / レーザー処理 |
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| Research Abstract |
Various adhesion promoters have been developed and are in wide use. However, the treatment of the dentin as an adherent is a more important issue. This study evaluated the effects of the pretreatment of the cavity on microleakage of the composite resin restorations with dentin margens. The labnial surfaces of bovine teeth were ground until the dentin was exposed. Two standardized round cavities were prepared side by side. Four kinds of cleaning agents; 3% aluminum lactate, 10% ascorbic acid, 10% citric acid and 10% phosphoric acid were applied for 60 seconds to one of the two cavities. The other was left without cleaning. After bonding, a composite resin was inserted into cavity. The restored teeth were thermocycled, prior to immersion in dye for 24 hours.
The dentin bonding agent singly could not prevent dye penetration at the cervicaal dentin margin, and prior to bonding the pretreatment of dentin with some cleaning agents was effective for decreasing microleakage.
We investigated the possibility of treating the smear layer by laser irradiation. The surface of the smear layer was irradiated with a laser, and the changes were observed under a scanning electron microscope. A Nd-YAG laser and CO_2 laser were used in defocus. The results showed that both lasers induced changes in the smear layer. Depending on the irradiation level, the smear layer on the intertubular dentin was satisfactorily treated, with the tubular orifices closed.
Next, we determined the penetration of 1% methylene blue form the dentin surface when irradiated by both lasers under various conditions. It was found that while the dye applied to a non-irradiated dentin surface penetrated deeply over the entire area, an irradiated surface blocked dye penetration. This finding was also observed at low energy densities of 25-50 J/cm^2,which is very interesting from the standpoint of preserving dental pulp.
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