| Project/Area Number |
04454470
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Osaka University |
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Principal Investigator |
TORII Mitsuo Osaka Univ.Fac.Dentistry Assoc Prof., 歯学部, 助教授 (30116066)
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| Co-Investigator(Kenkyū-buntansha) |
YOKOTA Wakao Osaka Univ.Fac.Dentistry Instructor, 歯学部, 助手 (00230649)
TAKESHIGE Fumio Hospital attached to the Fac.Dentistry Instructor, 歯学部・附属病院, 助手 (60206969)
TSUCHITANI Yasuhiko Osaka Univ.Fac.Dentistry Prof., 歯学部, 教授 (40028709)
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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 |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1992: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Keywords | Composite resin / Fiber reinforcement / Elastic filler / Milled fiber / 不連続繊維分散強化 |
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| Research Abstract |
Composite resins have improved their mechanical properties by increasing the filler contenst. Consequently filler content exceeds 85 wt% and the mechanical properties of composite resins almost equal to that of amalgam. On the other hand, the brittleness of composite resins becomes very high. For that reason, the problems such as marginal fracture and wear remain unsolved. The purpose of this study is to make composite resin tough by adding elastic fillers. We used milled E-glass fiber for the elastic filler. Control composite resin contained 80 wt% of silica filler. From 0 to 65 wt% of silica filler was changed with milled fiber. The compressive strength decreased as milled fiber content increased. However, flexural strength, elastic modulus and fracture toughness increased as milled fiber content increased. The more the aspect ratio of millled fiber was, the more notable the increase in these three properties was. Especially, the fracture toughness became 1.7 times bigger than control resin when 65 wt% of milled fiber, whose aspect ratio was 25, was added. Resistance to marginal fracture also increased as milled fiber content increased. However, this resistance became minimum when 50 wt% of milled fiber was added and more addition of milled fiber caused decreased of resistance to marginal fracture. The surface roughness of milled fiber containing composite resins after polishing or wear test agaist bovine enamel was not significantly different from a comercial posterior composite resin.
These results suggest that addition of milled fiber is very effective on toughening of composite resins and causes the increase in resistance to marginal fracture.
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