Evaluation of Effect of Fabrication Steps on Marginal Adaptation of CAD/CAM Zirconia-based Crowns in Comparison to Sintered PFM Crowns: An in Vitro Study

Abstract

Aims: This study aimed to compare and evaluate the effect of fabrication steps on marginal adaptation of CAD/CAM zirconia-based crowns in comparison to sintered PFM crowns. Materials and methods: Forty typhodont mandibular molar teeth were collected, a standardized protocol was followed for tooth preparation, after the tooth preparation 40 typhodont mandibular molar teeth were divided into two groups. Group I—20 CAD/CAM zirconia crowns and group II—20 sintered PFM restorations. Both the groups of crowns were analyzed for marginal fit during each step of fabrication, i.e., coping, after veneering, after cementation, and after thermomechanical loading. Each specimen was photographed using a stereomicroscope at 40× magnification to measure and evaluate the marginal discrepancy (MD). The results of a vertical MD of all tested fabrication stages were statistically analyzed using one-way analysis of variance (ANOVA), independent sample T-test. Results: In this study, the marginal gap was increased after every tested stage for both the groups. The mean marginal adaptation values were least in each stage of fabrication for CAD/CAM zirconia-based crowns (coping—104.98 μm, veneering—108.46 μm, after cementation—110.11 μm, thermomechanical loading—116.41 μm) compared to sintered PFM crowns (coping—128.87 μm, veneering—132.41 μm, after cementation—135.51 μm, thermomechanical loading—136.9 μm). Conclusion: The mean marginal adaptation values observed were all within the clinically acceptable range for both groups. Marginal adaptation of CAD/CAM zirconia-based crowns was better than sintered PFM crowns within each stage of fabrication.