| Project/Area Number |
13671996
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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 |
Conservative dentistry
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
YOSHIKAWA Takako Tokyo Medical and Dental University, Dept. of Restorative Sciences, Instructor, 大学院・医歯学総合研究科, 助手 (00182733)
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| Co-Investigator(Kenkyū-buntansha) |
TAKADA Tsunehiko Tokyo Medical and Dental University, Dept. of Restrative Sciences, Instructor, 大学院・医歯学総合研究科, 助手 (70282762)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | polymerization contraction stress / resin composite / light curing method / slow-start curing method / stepped curing method / ramped curing method / marginal leakage / cavity wall adaptation / Slow-start curing 法 / フロアブルレジン / 辺縁封鎖性 / Ramp射照法 / 辺縁封鎖法 / 曲げ強さ |
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| Research Abstract |
Light-cured resin-based composites are widely used in clinical practice because of the esthetic advantages, ease of use, excellent bonding to tooth structure, and improved mechanical properties.' However, the polymerization reaction of light-cured resin composites is faster than that of self-cured composites, which creates more gaps between the resin and cavity wall/floor than self-cured resin composites.
This projects was to evaluate the effect of light curing methods on the marginal sealing and cavity wall adaptation of resin composite restorations, and on the hardness at the top and bottom surfaces of a body of resin composite; Cylindrical cavities were prepared on flat bovine dentin surfaces. The teeth were restored with adhesive systems followed by light-cured composite. The resins were cured with NEW LIGHT VL-ll (VL-ll, GO), Co-bee (CBS GO) and experimental light curing unit (EP, GO); Group 1: VL-ll 700 mW/cm^2 s; Group 2: OB (Ramped curing) 210 mW/cm^2 to 700 mW/cm^2 5 s + 700 mW/cm^2 s; Group 3: EP (Stepped curing) 270 mW/cm^2 s + 5 s (interval) + 600 mW/cm^2 50 s. After thermocycling for 500 cycles between 500 and 5500 with a dwell time' 30 second, dye penetration tests around the cavity margin and cavity wall adaptation on cut surface were carried out. Dye penetration length was calculated as a percentage of the total cavity wall length.
The ramped and stepped curing significantly improved marginal sealing and resin composite adaptation to the cavity wall. These slow-start curing methods caused accelerating the hardening at the bottom surfaces of the resin composite.
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