2002 Fiscal Year Final Research Report Summary
Effect of Polymerization Shrinkage on Resin Composite Restorations and Effective Countermeasures against it
| Project/Area Number |
12307043
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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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 | The Nippon Dental University (2001-2002)
Tokyo Medical and Dental University (2000) |
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Principal Investigator |
SHINKAI Koichi The Nippon Dental University, School of Dentistry at Niigata, Associate, 歯学部, 助教授 (90147843)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Masashi Nihon University, School of Dentistry, Assistant Professor, 歯学部, 講師 (70239391)
UNO Shigeru Hokkaido University, Graduate School of Dental Medicine, Assistant Professor, 歯学部附属病院, 講師 (00168733)
YOSIKAWA Takako Tokyo Medical and Dental University, Graduate School, Instructor, 大学院・医歯学総合研究科, 助手 (00182733)
KUBO Shisei Nagasaki University, Graduate School of Biomedical Sciences, Associate, 歯学部附属病院, 助教授 (80145268)
IKEMI Takuji Nihon University, School of Dentistry at Matsudo, Professor, 松戸歯学部, 教授 (80102565)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Resin composite / Polymerization shrinkage / Irradiation method / Contraction stress / Enamel cracks / low-viscosity resin / Contraction gap / Marginal sealing |
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| Research Abstract |
Shinkai K revealed that composite restorations cured with low light intensities exhibited better cavity adaptation than those cured with high light intensities. Inai N reported that there was no significant differences among the the volume of polymerization shrinkage of the resin composite cured with various light irradiation units, if the degree of conversion of the resin composite was equivalent. Yoshikawa T reported that slow-start curing method showed better marginal sealing and cavity wall adaptation than the conventional curing method. Uno S proved the efficacy of the slow-curing method combined with an interval between the two irradiation applications, one with low intensity and one with high intensity. Ikeda T revealed that the bonding system employed showed lower microtensile bond strength to enamel surfaces that were stressed perpendicular to the prism long axis compared to those stressed parallel to the prism long axis. Ikemi T reported that the elastic modulus of restorativ
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e materials had an effect on polymerization shrinkage stress, and low viscosity resins exhibited lower shrinkage stress than hybrid resin. Miyazaki M reported that shorter irradiation time with the use of high intensity light might not be enough for curing light -cured resin composites. Kubo S revealed that the use of a low-viscosity resin-based composite liner relieved polymerization shrinkage stress on the adhesive interfaces generated by thermal and mechanical stress. Fujitani M revealed that the subsurface layer of lased dentin was mechanically weakened due to the formation of structural defects and a heat-denatured layer, leading to considerably lower adhesive properties of resin bonding systems. Ishizaki Y and Fukushima M reported that there was no significant difference in the development of marginal enamel cracks among the composite restorations cured with a slow-start curing unit, a high intensity curing unit and a conventional curing unit. Matsui O reported that degrees of composite restoration strain led to polymerization shrinkage which increased in the following order ; curing with an LED lamp, halogen lamp and xenon lamp. Matsuzawa N developed a newly designed method for measuring polymerization linear shrinkage of light-cured flowable resin composites. Tamura N investigated the microleakage of tunnel-shaped cavity composite restorations restored by various filling techniques, and the results showed that incremental filling for cervical and occlusal portions exhibited the best marginal sealing. Less
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