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Purpose An in vitro study to compare the marginal fit of cobalt‐chromium (Co‐Cr) metal copings fabricated with selective laser melting (SLM), computer‐aided design and computer‐aided manufacturing (CAD/CAM) milling, and lost‐wax (LW) techniques, on abutments with two different antirotational features. Materials and Methods A total of 60 stainless steel abutments with the same length and convergence angles were fabricated using a numerical control machining. Half of the abutments had one flat plane, while the other half had three grooves as an antirotation feature. Thirty abutments of each kind were then divided into three subgroups, and metal copings were fabricated with SLM, CAD/CAM milling, or the LW technique (n = 10). The metal copings were cemented with polycarboxylate cement. Marginal gap measurements were performed using a stereomicroscope at a magnification of × 45 and data were analyzed with two‐way analysis of variance (ANOVA) tests. Results The LW (p = 0.002) and CAD/CAM (p < 0.001) techniques exhibited increased marginal gaps on the abutments with a three groove antirotational feature; however, no significant difference was detected with the SLM technique (p = 0.259). The copings fabricated with the SLM technique demonstrated significantly lower gap values in both abutment types (p < 0.001). Conclusion While all marginal gap values were within the clinically acceptable range (<120 µm), abutments with more antirotational grooves exhibited wider marginal gaps with the LW and CAD/CAM techniques.

SummaryBackground/Aim: The purpose of this study was to evaluate compatibility between visual and digital color measurement methods.Material and Methods: The color measurement components of intact natural maxillary right central incisor and left canine teeth of eighty patients were measured with visually shade guide and, digitally, with digital device. The color matchings were performed for each teeth on labial surfaces divided into three regions: cervical, middle and incisal. Ligthness, MLR (M: means middle hue, L designates greener, R designates redder) and chroma levels were assessed for each tooth on divided regions respectively. Measurements were performed by the same and experinced dentist with healthy eyes. The data were analyzed with Kappa and weighted Kappa coefficient (p< 0.05).Results: The compatibility between visual and digital methods did not exist for MLR and chroma. The compatibility between both methods were determined only for ligthness of maxillary central and canine teeth at all regions of labial surfaces.Conclusions: There was compatibility only for ligthness of intact natural teeth at all regions with both methods.

Background and Aim Methods and Materials