| Project/Area Number |
08457505
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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 | Kagoshima University |
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Principal Investigator |
TORII Mitsuo Dental School, Kagoshima University, Professor, 歯学部, 教授 (30116066)
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| Co-Investigator(Kenkyū-buntansha) |
ITOTAGAWA Tokunori Osaka University, Dental School, Research Associate, 歯学部, 助手 (70232494)
IMAZATO Satoshi Osaka University, Dental School, Research Associate, 歯学部, 助手 (80243244)
SUWA Motoko Dental School, Kagoshima University, Research Associate, 歯学部, 助手 (80206599)
TSUKADA Gakuji Dental Hospital, Kagoshima University, Research Associate, 歯学部・附属病院, 助手 (70236850)
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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 |
¥7,300,000 (Direct Cost: ¥7,300,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | antibacterial resin / ion-exchange / reversibility / cationic antibacterial agent |
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| Research Abstract |
The aim of this investigation is to give the long lasting antibacterial activity of agent release type to tooth coating material for caries prevention.
Methactylic acid was added to triethylene glycol dimethacrylate as a cation-exchanger and photoactivated by camphorquinone and 2-dimethylaminoethyl methacrylate. A cationic antibacterial agent cetylpiridinium chloride (CPC) was dissolved to this test resin. The resin was photopolymerized to make disc shaped specimens (10 mm in diameter and 2 mm in thickness).
The resin discs released CPC in buffers whose pHs were under 6.0, however, no release of CPC was observed in the pH over 6.5. The amount of CPC released increased as the pH of buffer decreased.
The resin discs also released CPC when they were soaked in pH 7.0 phosphate buffer and sodium chloride was added to increase the ionic strength. The higher the ionic strength went up, the more the amount of CPC was released. When the resin, which finished to release CPC, was soaked in aqueous s
… More
olution of CPC, it recovered the ability of releasing CPC in acidic buffers. These results suggest that this resin works as a cation-exchange resin and retains CPC reversibly by ionic bond.
The antibacterial activity of this resin was investigated in vitro and in vivo. At first S.mutans MT8148 was cultured in Brain Heart Infusion broth placed on the disc shaped specimen, but no viable cells were recovered. Next, the discs were suspended in sucrose containing HI broth inoculated with S.muttons MT8148 and cultured. After 24 hr culture, the bacterial cells adhered on the disc specimen were observed by SEM and the amount of collected cells were determined spectrophotomechally. Significantly less bacterial cells (1.7% of control resin specimen containing no CPC) were recovered and the anti-plaque activity was not influenced by saliva treatment. Finally, the antibacterial and anti-plaque activity was confirmed in vivo by using beagle dogs. The number of bacterial cells accumulated on the test resin was o.7% of that on control resin.
The test resin reversibly retains CPC by ionic bond and releases CPC when the circumstance pH inclines to acidic. This mechanisms could provide dental resin with long lasting antibacterial activity of agent release type. The unique action of this test resin, releasing CPC only under acidic condition, would be ideal drug delivery system from the view point of caries etiology. Less
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