Comparison of the marginal gap of zirconia-fabricated copings generated by CAD/CAM and Copy-Milling methods

Introduction: This study was conducted to compare the marginal fit of single-tooth zirconia-based copings fabricated by CAD/CAM process (Cercon; Degudent) and Copy Milling (Dentium). Materials and Methods: One in vitro prepared abutment from one mandibular molar model served as a template for replication of 40 epoxy resin (highly filled) dies, which had been taken by polyvinyl siloxane impression material. Copings were manufactured on epoxy replicas by two processes: the CAD/CAM (Cercon; Degudent) (n = 20) and the Copy-Milling (Dentium) (n = 20) processes. Four measurements were performed for each surface coping (Buccal, Lingual, Mesial, and Distal). Data were analyzed by SPSS 16 statistical software using independent t-test. Results: There was a significant difference in the marginal gap values between CAD/CAM and Copy-Milling groups (P < 0.001). The mean value of the marginal gap (SD) for CAD/CAM Copings (56.87 μm) was significantly less than that of Copy-Milling (136.12 μm) (P < 0.001). Conclusion: The marginal fit of CAD/CAM copings was better than that of Copy-Milling copings.