| Project/Area Number |
10671821
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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 Mitsuo Tokyo Medical and Dental University, Faculty of Dentistry Lecturer, 歯学部, 講師 (10143596)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Bisphenol A / Dental material / Analysis |
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| Research Abstract |
The purposes of this study is to establish the method for microanalysis of bisphenol A contained in dental resins and then to ascertain whether bisphenol A is produced from unpolymerized monomers by decomposition reactions, etc. The evaluation of the possible reduction in bisphenol A amounts during polymerization was also chosen as the subject of the study.
1. Microanalysis of bisphenol A amounts
Quartz containers were used for microanalysis of bisphenol A amounts in order to eliminate the contamination with alkali metal ions as effectively as possible. A ratio of methanol/water=80/20 is most suitable for mobile phase of methanol-water mixture and a ratio of acetonitrile/water=60/40 for that of acetonitrile-water mixture. Microanalytical methods with the optimal design were established according to the properties of various test specimens.
2. Bisphenol A release from bisphenol A related compounds caused by their decomposition
Bis-DMA was quite easily decomposed into bisphenol A under the a
… More
cidic or basic environment. On the other hand, the formation of bisphenol A from BHP was not observed, although Bis-GMA was decomposed into BHP which is an intermediate formed during hydrolysis. From the facts described above, it was concluded that there is little possibility of the production of bisphenol A from Bis-GMA, since BHP intermediate in hydrolysis is extremely stable.
3. Interaction of bisphenol A with radicals formed during the cure of resins
Induction period increased with an increase in additional amounts of bisphenol A when 2,2'-azobis(isobutyronitrile) was used as an initiator. This revealed that bisphenol A is a typical polymerization inhibitor. Bisphenol A produced longer induction periods than hydroquinone in the polymerization initiated by benzoyl peroxide (BPO), which indicated that the former acts as an inhibitor more effectively than the latter in the presence of BPO. It was supposed that bisphenol A is no longer present in dental resins at the start of their curing, since bisphenol A contained in resins as an impurity is consumed by the reaction with initiator radicals. Less
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