| Project/Area Number |
09672022
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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 |
補綴理工系歯学
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| Research Institution | ASAHI UNIVERSITY |
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Principal Investigator |
KAMEMIZU Hideo ASAHI UNIVERSITY, SCHOOL OF DENTISTRY, ASSISTANT, 歯学部, 助手 (00152877)
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| Co-Investigator(Kenkyū-buntansha) |
ADACHI Masanori ASAHI UNIVERSITY, SCHOOL OF DENTISTRY, LECTURER, 歯学部, 講師 (60076057)
DOI Yutaka ASAHI UNIVERSITY, SCHOOL OF DENTISTRY, ASSOCIATE PROFESSOR, 歯学部, 助教授 (40116067)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | ESR / Light-cured composite resein / Unreacted double bond / Free radical / Polymer radical / Radical concentration / 未反応二重結合 / 未反応モノマー / 光重合型コンポジットレジン / ラジカル |
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| Research Abstract |
It is evident that free radicals produced in visible light-cured resins play an important role in polymerization. With the techniques used so far, however, it is practically impossible to directly investigate the free radicals in specimens. In this study, electron spin resonance (ESR) spectroscopy was applied to analysis unreacred double bond and measure kind and amount of free radical produced in the visible light-cured composite resin after light irradiation. In the ESR measurement, it is difficult to directly measure the unreacted double bond amount in specimens. However, the determination of unreacted double bond amount is possible by measuring the amount of radicals regenerated by prolonged irradiation for 10 min at 3 min after first irradiation. In this measurement, it was expected that the unreacted double bond amount would increase and unreacted monomer probably increase with decreasing the irradiation time.
The kind of radical from monomer for dental use showed that form methacrylate group and did not influenced by the monomer kind. The radical concentration/amount in propagation increased rapidly during irradiation and approached a plateau at a certain time. The polymer radical regenerated from unreacted double bond and/or unreacred monomer decreased with an increase in irradiation time. The amount of regenerated radical in specimens could afford to elucidate the unreacted double bond amount. This result indicates that ESR can give useful information to elucidate the unreacted double bond amount and the dynamic behavior of radicals in composite resin.
In other experiment, the effect of elapsed time on post-polymerization is also examined by measuring the radical amount variation after irradiation.
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