This study compared the internal and marginal gap between CAD/CAM copings to determine the clinical acceptability. Hundred dental stone duplications of a metal major maxillary molar die were fabricated and separated into five. All copings were produced by milling and laser sintering method in the form of twenty groups. At x 180 magnification, marginal and internal gaps of each coping were measured at 75 points, and a total of 7500 measurements were performed for six regions on digital photographs taken with video microscope. Data were analyzed using one-way analysis of variance (ANOVA) and post hoc test (Tukey and Bonferroni). The internal and marginal gaps of the milling group were significantly larger than the laser sintering group (P < 0.05). The results of this in vitro study show that CAD/CAM milled Co-Cr copings exhibit larger marginal and internal gap values than copings by laser sintering method. All copings were presented clinically acceptable marginal and internal accuracy. Milling and laser sintering systems are suitable for manufacturing of copings.

computer-aided design, dental marginal adaptation, dental crown