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Document Type |
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Article In Journal |
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Document Title |
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Effects of Tooth Preparation Burs and Luting Cement Types on the Marginal Fit of Extracoronal Restorations Effects of Tooth Preparation Burs and Luting Cement Types on the Marginal Fit of Extracoronal Restorations |
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Document Language |
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English |
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Abstract |
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Purpose: Although surface roughness of axial walls could contribute to precision of a
cast restoration, it is unclear how the roughness of tooth preparation affects marginal
fit of the restoration in clinical practice. The purpose of this study was to describe
the morphologic features of dentin surfaces prepared by common rotary instruments
of similar shapes and to determine their effects on the marginal fit for complete cast
crowns.
Materials and Methods: Ninety crowns were cast for standardized complete crown
tooth preparations. Diamond, tungsten carbide finishing, and crosscut carbide burs of
similar shape were used (N = 30). The crowns in each group were subdivided into
three groups (n = 10) for use with different luting cements: zinc phosphate cement
(Fleck's), glass ionomer cement (Ketac-Cern), and adhesive resin cement (Panavia
21). Marginal fit was measured with a light microscope in a plane parallel to the tooth
surface before and after cementation between four pairs of index indentations placed at
equal distances around the circumference of each specimen. Difference among groups
was tested for statistical significance with analysis of variance (ANOVA) followed by
Ryan-Einot-Gabriel-Welsch Multiple Range Test (a = 0.05).
Results: Analysis of measurements disclosed a statistically significant difference for
burs used to finish tooth preparations (p < 0.001); however, luting cement measurements
were not significantly different (p = 0.152). Also, the interaction effect was not
significantly different (p = 0.685). For zinc phosphate cement, the highest marginal
discrepancy value (100 ± 106 J-Lm) was for tooth preparations refined with carbide
burs, and the lowest discrepancy value (36 ± 30 J-Lm) was for tooth preparations refined
with finishing burs. For glass ionomer cement, the highest marginal discrepancy value
(61 ± 47 J-Lm) was for tooth preparations refined with carbide burs, and the lowest
discrepancy value (33 ± 40 J-Lm) was for tooth preparations refined with finishing
burs. For adhesive resin cement, the highest marginal discrepancy value (88 ± 81 J-Lm)
was for tooth preparations refined with carbide burs, and the lowest discrepancy value
(19 ± 17 J-Lm) was for tooth preparations refined with finishing burs.
Conclusions: Marginal fit of complete cast crowns is influenced by tooth preparation
surface characteristics, regardless of the type of luting agent used for cementation.
Tooth preparations refined with finishing burs may favor the placement of restorations
with the smallest marginal discrepancies, regardless of the type of cement used. |
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ISSN |
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101111 |
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Journal Name |
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The American College of Prosthodontists |
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Volume |
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18 |
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Issue Number |
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1 |
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Publishing Year |
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2005 AH
2005 AD |
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Article Type |
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Article |
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Added Date |
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Saturday, November 7, 2009 |
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Researchers
| محمد عياد | Ayad, Mohamed | Investigator | Doctorate | |
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