| Project/Area Number |
04555187
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学・無機材料工学
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| Research Institution | Okayama University |
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Principal Investigator |
MIURA Yoshinari Okayama Univ., Faculty of Eng., Prof., 工学部, 教授 (80032952)
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| Co-Investigator(Kenkyū-buntansha) |
ASADA Masayuki Kuraray Medical Lab., Researcher, メディカル研究開発室, 研究員
NANBA Tokuro Okayama Univ., Faculty of Eng., Lecturer, 工学部, 講師 (80218073)
OSAKA Akiyoshi Okayama Univ., Faculty of Eng., Assoc.Prof., 工学部, 助教授 (20033409)
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| Project Period (FY) |
1992 – 1993
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| Project Status |
Completed (Fiscal Year 1993)
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| Budget Amount *help |
¥10,900,000 (Direct Cost: ¥10,900,000)
Fiscal Year 1993: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1992: ¥8,600,000 (Direct Cost: ¥8,600,000)
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| Keywords | glass filler / dental resin / release of fluoride ions / controlled releasing rate |
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| Research Abstract |
Composite resins composed of PMMA as matrix and glass powders as fillers for restoration of decayd or injured teeth have been researched extensively, which are believed to be effective in cohesiveness with tooth enamel. However, the chemical durability, hardness, transparency of the fillers are to be improved. Furthermore, the dental materials having further functions such as controlled release of ions are greatly desired. This research is to develop glass fillers having F^- and Sr^<2+> releasing characteristic in order to fluorizate natural teeth for preventing tooth decaying. The optimization of required other physical and chemical properties of the glass fillers is also investigated.
The selected glass systems were SiO_2-B_2O_3-BaO-SrO-AlF_3, SiO_2-B_2O_3-Al_2O_3-BaO-SrF_2, SiO_2-B_2O_3-Al_2O_3-BaF_2-SrF_2 and SiO_2-B_2O_3-SrO-AlF_3-BaF_2. The dependences of various properties including extraction rates of ions on their compositions were researched. The summarized results are as foll
… More
ows :
1. The extraction of ions from glasses was diffusion controlled after a reaction process of extraction at the initial stage.
2. Aluminum element in glass playd a role of reducing the total extraction of ions. It was explained that the formation of protective films being rich in Al^<3+> ions prevented further extraction of ions besides 4-coordinaded Al^<3+> ions improved the glass structure.
3. Adding of boron element increased the total extraction of ions. Besides it was due to the poor durability of B-O-B structure unit in water, the dissolvability of B_2O_3 rich phases in phase separated glasses was another reason because increased tendency of phase separation was observed due to increasing of B_2O_3.
From the above results, it is concluded that the extraction of ions from glass are controllable by using the effect of Al^<3+> ions and selecting glass composition, and glasses with controlled releasing ability of ions can also be prepared by useful application of phase separation characteristic of glass. Less
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