Evaluation of the Internal and Marginal Discrepancies of Co-Cr Metal Copings Prepared via CAD/CAM and Conventional Casting

Abstract

The aim of this study was to assess the internal and marginal discrepancies of chromium-cobalt (Co/Cr) copings fabricated using different techniques. A typodont molar tooth was prepared and replicated in die stone and scanned. Forty Co-Cr alloy copings were produced using four different production techniques: conventional casting (C-group), direct metal laser sintering (DMLS-group), micro-stereolithography/casting combination (mu SLA-group), and computer-aided milling (M-group) (n = 10). The internal and marginal discrepancies at various reference points were determined via digital microscopy. Analysis of variance (ANOVA) and Tukey's multiple comparisons tests were used for statistical analysis (p=0.05). The marginal and cervical discrepancies of the C-group were similar to those of the M-group (p>0.05) and better than those of the mu SLA-group (p<0.05). The marginal and internal discrepancies of all groups were within clinically acceptable limits, but further improvements in the mu SLA and DMLS techniques may be required prior to clinical implementation.