Evaluation of the Marginal and Internal Fit of Implant-Supported Metal Copings Fabricated with 3 Different Techniques: An In Vitro Study.

Abstract

To compare the marginal and internal fit of cobalt-chromium (Co-Cr) alloy copings fabricated by with lost wax technique (LW), computer-aided design and computer-aided manufacturing (CAD/CAM), and direct metal laser sintering (DMLS). Thirty-six tissue level, straight titanium abutments were screwed onto implant replicas. All specimens were embedded in acrylic resin and randomly divided into 3 subgroups according to the fabrication of metal coping: LW, CAD/CAM, and DMLS. In total, 36 (n = 12/group) Co-Cr implant-supported metal copings were prepared. Marginal, intermarginal, axial, and occlusal fits of each coping were measured using the silicone replica technique. The data were evaluated statistically using one-way ANOVA and Bonferioni post-hoc test (α = 0.05). The CAD/CAM group showed significantly lower marginal fit than the LW group and DMLS groups (p < 0.001). The marginal fit of the LW group was not significantly different from the DMLS group (p = 0.721). No significant difference found among the fabrication methods in terms of intermarginal fit (p = 0.913). The CAD/CAM group showed lower axial fit than the LW group (p = 0.026), but there was no statistical difference between the DMLS group and the LW (p = 0.999) and CAD/CAM groups (p = 0.247). No significant differences found among the fabrication methods in terms of occlusal fit (p = 0.158). The LW and DMLS groups showed better marginal fit compared to the CAD/CAM group; however, the CAD/CAM group was better than the LW group in terms of axial fit. All fabrication methods demonstrated similar intermarginal and occlusal fit.