| Project/Area Number |
62870080
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 | Meikai University |
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Principal Investigator |
HASHIMOTO Hirokazu Meikai Uni/Sch Dentistry, Professor Chairman, 歯学部, 教授 (00049347)
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| Co-Investigator(Kenkyū-buntansha) |
森岡 茂夫 佐藤製薬株式会社, 研究開発部, 部長
NAKAJIMA Hiroshi Meikai Uni/Sch Dentistry, Instructor, 歯学部, 助手 (80188961)
NAGAYAMA Katsuya Meikai Uni/Sch Dentistry, Assistant Professor, 歯学部, 講師 (40105630)
YAMAGA Taniichiro Meikai Uni/Sch Dentistry, Instructor, 歯学部, 助手 (90049403)
ARAI Kouichi Meikai Uni/Sch Dentistry, Associate Professor, 歯学部, 助教授 (90049396)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥7,400,000 (Direct Cost: ¥7,400,000)
Fiscal Year 1989: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1987: ¥4,000,000 (Direct Cost: ¥4,000,000)
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| Keywords | Caries preventive / Preventive materials / Fluoride / LD50 / Toxicity / Enamel surface / エナメル質脱灰形態 |
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| Research Abstract |
In the previous research project (58420047), an indium fluoride solution was found to provide approximately twice and more than 3 times as much as the acid-resistance to human enamel when compared to a stannous fluoride and a sodium fluoride which have been frequently used for carious preventive agents, respectively. The pharmacological evaluation of the fluoride solutions, the morphological evaluation of decalcified human enamel surface treated with the fluoride solutions and mechanical and physical properties of dental cements containing the fluorides were investigated in the present research project (62870080).
1) Pharmacological evaluation ; (1) the indium fluoride showed antimicrobial action against obligate anaerobe periodontopathic bacteria such as B.gingivalis and B.intermedius ; (2) the indium fluoride revealed no noticeable metagenicity ; and (3) the LD_<50> value of acute toxicity for indum fluoride(522.3mg/kg) was higher than that for sodium fluoride(237.2mg/kg) or stannous
… More
fluoride(416.0mg/kg). This implies that the indium fluoride showed the least acute toxicity as compared to other fluorides tested.
2) Morphological evaluation : The enamel surfaces treated with the indium fluoride solution or the experimental paste containing indium fluoride were decalcified(etched) using an acetic, a citric or a lactic buffered solution of pH 4.0, and then observed using a scanning electron microscope. Although the surfaces decalcified using each acidic bufferd solution did not reveal the identical molphologies, the indium fluoride treatment was effective to provide the acid-resistance to human enamel at the early stage of decalcification.
3) mechanical and physical properties of dental cements containing the indium fluoride : The mechanical and physical properties of zinc phosphate, polycarboxylate or glass ionomer cement admixed with the indium fluoride powder in the cement powder or the indium fluoride solution in the cement liquid were determined according to the American Dental Association Specification(ADAS). The compressive strength and the solubility and disintegration of each cement containing the indium fluoride solution in the cement liquid satisfied the ADAS and the incorporation of indium fluoride to the cement liquid decreased the solubility and disintegration of the cements tested.
The results obtained suggest the potential of development in new dental material to prevent the secondary caries. Less
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