CAD-CAM and heat-press: Comparison of internal and marginal fit of lithium disilicate copings

The aim of this in vitro study is to compare the performance of digital and conventional methods in the manufacture of single copings in terms of the internal and marginal fit. Twenty-four prefabricated titanium Cone Morse Exact abutments of the lateral anatomical type were used to manufacture 24 lithium disilicate copings in the CAD-CAM Ceramill (n = 12) and heat-press (n = 12) systems. The copings were cemented using a self-adhesive resin cement (RelyX U-200; 3M ESPE) and then cut vertically. The cement line was photographed using an optical microscope at ×100 and ×200 magnification and then the internal and marginal regions were measured. The mean values of fits, for the CAD-CAM and heat-press techniques, respectively, were (μm): angular regions, 81.8 and 75.3; linear regions, 63.1 and 60.1; incisal regions, 171.1 and 114.7; marginal discrepancy, 74.1 and 75.2; and absolute marginal discrepancy, 99.5 and 96.2. MANOVA test showed that there is an effect of the techniques on the regions (p < .05). The effects of laboratories and the interaction between laboratories and techniques on the regions were not statistically significant (p > .05). The techniques evaluated presented clinically acceptable results for the marginal fit. However, the conventional method performed better for the internal fit. RESEARCH HIGHLIGHTS: Scientific evidence regarding the methods of making prosthesis can help the dental professional in decision-making. Digital and conventional methods is both good in the manufacture of single copings in terms of the internal and marginal fit.