| Project/Area Number |
12671874
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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 | Tokyo Medical and Dental University |
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Principal Investigator |
KADOMA Yoshinori Tokyo Medical and Dental University, institute of Biomaterials and Bioengineering, Associate Professor, 生体材料工学研究所, 助教授 (00092403)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Mitsuro Iwate Medical University School of Dentistry, Professor, 歯学部, 教授 (10143596)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥3,200,000 (Direct Cost: ¥3,200,000)
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| Keywords | Bisphenol A / Dental resin / Radical |
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| Research Abstract |
The amount of bisphenol A can be dynamically changed by the reaction with radicals and by the hydrolysis of leachable compounds. The purposes of this study is to provide a clear instruction of possible leaching of bisphenol A from dental resins by an analysis of leaching phenomena of bisphenol A, taking into consideration of the dynamic change in the amount.
1. Radical polymerization in the presence of bisphenol A
In order to clarify the effect of bisphenol A on radical polymerization, bisphenol A was added to polymerization mixture of methyl methacrylate(MMA) and the reaction was precisely examined. It was concluded that bisphenol A is unable to exist in the polymerization mixture after the polymerization of resin, since bisphenol A acted typically as an inhibitor and a minor amount of the compound in dental resins would be used up during polymerization.
2. Clarification of radical-scavenging mechanism by comparing bisphenol A with its related compounds
To elucidate the radical-scavenging mechanism of bisphenol A, its radical-scavenging phenomenon in the polymerization of MMA was compared with those of its related compounds, and the result was examined. The stoichiometric factor (n) of bisphenol A was revealed to be 1.8. It was indicated that bisphenol A with a high inhibitive activity is oxidized as a result of the radical interaction.
3. Dynamic leaching phenomenon of bisphenol A and production of bisphenol A from leachable compounds
It was demonstrated that benzoyl peroxide(BPO) is unreactive to bisphenol A coexisting in dental resins, since no reaction product of bisphenol A was newly found even after 549 hr of reaction with BPO. On the other hand, several tens ppm of bisphenol A in visible light-curing resin was consumed during the cure of resins. Therefore, it was concluded that leaching of bisphenol A out of cured resins or production of bisphenol A as a result of hydrolysis does not practically occur, when its amount in dental resins is 10 ppm or less.
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