| Project/Area Number |
04671170
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Conservative dentistry
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| Research Institution | Nihon University School of Dentistry |
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Principal Investigator |
KURODA Takashi Nihon Univ.DENT.Associate Professor, 歯学部, 助教授 (80059790)
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| Co-Investigator(Kenkyū-buntansha) |
ONOSE Hideo Nihon Univ.DENT.Professor, 歯学部, 教授 (70059426)
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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 |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1992: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Resin cements / Dual-cured type / Pre-mix activation |
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| Research Abstract |
IT has been reported that the bond strength of dual-cured resin cements is influenced by the light energy through the resin materials. The purpose of this study was to examine the relationship between the order in which a dual-cured resin cement is light activated and the bond strength of the reshin cement. Also, the setting time and film thickness with various irradiation procedures were evaluated from the clinical perspective.
Three experiments were designed to study the influence of the following factors : (1) pre-mix activation (activation of only the liquid prior to mixing), (2) post-mix activation according to the manufacturer's instructions, (3) no-light activation.
The setting time of cement mix with pre-mix activation was shorter than that with no activation. No difference was observed between the specimen with pre-mix activation and that with no activation regarding the film thickness of the cement mix. The compressive strength and flexural strength were influenced by irradiation sequences. The Knoop Hardness Number on the longitudinally sectioned surface increased with the pre-mix activation. The pre-mix irradiation to the liquid before cement mixing is effective even without irradiation to the cement after placement. Camphoroquinone in the liquid is placed in a reactive condition by activation. This condition apparently generates free radicals and continues during handling time. This active condition makes the pre-mixed bond strength without irradiation after placement.
Further studies are needed to define the kinetics and mechanisms of the camphoroquinone curing system.
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