| Project/Area Number |
10671793
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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 | Nagasaki University |
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Principal Investigator |
KUBO Shisei Nagasaki University, Hospital attached to School of Dentistry, Assistant Professor, 歯学部・附属病院, 講師 (80145268)
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| Co-Investigator(Kenkyū-buntansha) |
TAJIMA Kiyoshi Kyushu Dental College, Assistant Professor, 歯学部, 講師 (60155075)
YOKOTA Hiroaki Nagasaki University, School of Dentstry, Instructor, 歯学部, 助手 (90301366)
KAWAGUCHI Masahiro Nagasaki University, School of Dentstry, Instructor, 歯学部, 助手 (40084248)
CHEN Ker-kong Kyushu Dental College, Instructor, 歯学部, 助手 (20207327)
渡邊 太平 長崎大学, 歯学部・附属病院, 助手 (10220899)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Cervical lesions / Bruxism / Microleakage / Finite element method / Stress distribution / Cavity forms / Flexural load cycling / Self-etching primer system |
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| Research Abstract |
1. Shallow wedge-shaped and U-shaped cavities were prepared at cervical region on labial surfaces of bovine teeth and restored with self-etching primer adhesive systems which showed similar bond strength to enamel and dentin. Microleakage of these cavities were investigated under flexural loading which simulate bruxism (eccentric occlusal force). In the case of the Shallow wedge-shaped cavities, microleakage occurred only at the incisal walls, while in the U-shaped cavities, it occurred mainly at the apical walls.
2. The strain, which were generated both at the incisal and apical walls by the same load as in the microleakage test, were determined using strain gauges. In the case of the Shallow wedge-shaped cavity, the incisal wall had a markedly greater strain than the apical wall. In the case of the U-shaped cavity, there was no significant difference in the magnitude of strain between the incisal and apical walls.
3. Strain and stress distribution (around the cervical cavities) on the same conditions as microleakage test were mathematically analyzed by two-dimensional finite element method. The obtained data was compared with the strain gauge data. The results corroborated that our analytical models were useful to study stress distribution within the restored teeth. In the case of the Shallow wedge-shaped cavity, the incisal wall had significantly greater normal stress than the apical wall. In the case of the U-shaped cavity, the incisal wall had less normal stress than the apical wall. We plan to make three-dimensional models to investigate stress distribution as accurately as possible.
4. The overall findings suggest that stress distribution induce by occlusal forces has an effect on the microleakage patterns of cervical resin composite restorations.
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