Marginal fit of the digident CAD/CAM zirconia ceramic crowns

Kim, Yong Sun; Yang, Jae Ho

Abstract

Statement of problem. There have been many studies about marginal discrepancy of single restorations made by various systems and materials. However most of the 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 the Digident CAD/CAM zirconia ceramic crowns. Purpose. The purpose of this study was to compare the marginal fit of the anterior single restorations made by using the Digident CAD/CAM zirconia ceramic 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. Material and Methods. The crowns were made from one extracted maxillary central incisor prepared with a 1mm shoulder margin and 6.taper walls by milling machine. The in vitro marginal discrepancies of the digident CAD/CAM zirconia ceramic crowns and control groups(metal ceramic crowns) were evaluated and compared. Twenty 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.
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 88+/-10microm for the control (metal-ceramic crowns), 92+/-4microm for Digident CAD/CAM zirconia ceramic crowns. 2. Marginal gap between Digident CAD/CAM zirconia ceramic crowns and metal ceramic crowns did not show significant difference (P>.05). 3. The Digident CAD/CAM zirconia ceramic crowns and metal ceramic crowns showed clinically acceptable marginal discrepancy.