| Project/Area Number |
14370618
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Osaka University |
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Principal Investigator |
TAKESHIGE Fumio Osaka University, Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (60206969)
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| Co-Investigator(Kenkyū-buntansha) |
KINOMOTO Yoshifumi Osaka University, Dental Hospital, Assistant Professor, 歯学部附属病院, 講師 (10252694)
HAYASHI Mikako Osaka University, Graduate School of Dentistry, Instructor, 大学院・歯学研究科, 助手 (40271027)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥11,700,000 (Direct Cost: ¥11,700,000)
Fiscal Year 2004: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2003: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2002: ¥5,800,000 (Direct Cost: ¥5,800,000)
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| Keywords | Fatigue crack propagation test / Tooth-colored inlay / Ceramic inlay / Marginal deterioration / Fractography / Cement line / セラミッックインレー |
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| Research Abstract |
We investigated quantitatively and morphologically analyzed and clarified the marginal changes of ceramic inlays and determined the mechanism for those changes. Marginal disintegration at the functional cusp area was significantly greater than at the non-functional cusp area (Wilcoxon signed-ranks test, p<0.05). Quantitative measurement and fractographic examination identified a sequential three-stage pattern of marginal deterioration ; initial rapid progress of wear of resin composite cement in the first stage, followed by a second stage without any remarkable visible change, then rapid progression of microfractures of ceramics and/or enamel in the third stage. Boundaries between the first and second stage were found in the six and 21-month period, and those between the second and third stage at 72 months. It was concluded that longitudinal marginal deterioration of ceramic inlays progressed in a sequential three-stage pattern.
We established an in vitro acceleration test of the margin
… More
al deterioration of ceramic inlays reproducing in vivo deterioration and to investigate the influence of the cement thickness on the marginal deterioration. It was confirmed that the in vitro acceleration test, which was a total of 1,600 cyclic wear loadings, successfully reproduced the in vivo three-sequential marginal deterioration quantitatively and morphologically. Significantly less marginal deterioration was observed in a specimen with the cement width of 100 μm (ANOVA and Scheffe's F test, p<0.05). It was suggested that cement width should be less than 100 μm to minimize the marginal deterioration of ceramic inlays.
A significant correlation was found to exist between explorer tip diameter and the Alfa/Bravo boundary for horizontal gaps, but not for vertical steps. It was suggested that visual inspection aided and unaided with loupes had no significant effect on the evaluation of simulated marginal discrepancies. The findings highlight the importance of the traditional dental explorer - in the absence of a more discriminatory device, in the assessment of marginal discrepancies in restorations. Less
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