In vitro marginal fit of the computer-aided milled cercon crowns
장재윤, 양재호, 이재봉, 한중석,
소속 상세정보
장재윤 ( Chang Jae-Yoon ) - 서울대학교 치과대학 치과보철학교실
양재호 ( Yang Jae-Ho ) - 서울대학교 치과대학 치과보철학교실
이재봉 ( Lee Jai-Bong ) - 서울대학교 치과대학 치과보철학교실
한중석 ( Han Jung-Suk ) - 서울대학교 치과대학 치과보철학교실
KMID : 0362420050430030306
Abstract
Statement of problem: There have been many studies about marginal discrepancy of single restorations made by various systems and materials. But most of statistical inferences are not definite because of sample size, measurement number, measuring instruments, etc. And there have been few studies about the marginal fit of Computer-aided Cercon crowns.
Purpose: The purpose of this study was to compare the marginal fit of the anterior single restorations made using computer-aided milled Cercon crowns with metal-ceramic restorations and to obtain more accurate information by using a large enough sample size and by making sufficient measurements per specimen.
Materials & Methods: The in vitro marginal discrepancies of computer-aided milled Cercon crowns and control groups (metal ceramic crowns) were evaluated and compared. The crowns were made from one extracted maxillary central incisor prepared by milling machine. 30 crowns per each system were fabricated. Measurements of a crown were recorded at 50 points that were randomly selected for marginal gap evaluation. Parametric statistical analysis was performed for the results.
Results: The means and standard deviations of the marginal fit were 85+/-22micrometer for the control group and 91+/-15micrometer for the Cercon crowns. The t-test of the marginal discrepancies between Cercon crowns and metal-ceramic crowns were performed. Significant differences were not found between groups (P=0.230>.05). Based on the criterion of 120micrometer as the limit of clinical acceptability, the mean marginal fits of Cercon crowns and metal-ceramic crowns were acceptable.
Conclusion: Within the limitations of this in vitro study, the following conclusions were drawn: 1. Mean gap dimensions and standard deviations at the marginal opening for maxillary incisal crowns were 85+/-22micrometer for the control (metal-ceramic crowns), 91+/-15micrometer for Cercon crowns. 2. The Cercon crowns showed slightly larger marginal gap discrepancy than the control but marginal gap between Computer-aided milled Cercon crowns and metal ceramic crowns did not showed significant difference (P>.05). 3. The Cercon crowns and metal ceramic crowns showed clinically acceptable marginal discrepancy.
키워드
marginal fit;cercon crown;Computer-aided milling system;Metal-ceramic crown
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