A comparative study of two CEREC software systems in evaluating manufacturing time and accuracy of restorations.

This study compared the manufacturing times and the accuracy of proximal and occlusal contacts on restorations produced by two different versions of CEREC 3 software, COS and 3D. Fourteen casts containing pre-existing inlay and onlay preparations of premolars and molars were mounted on articulators. A bite registration was made in maximum intercuspation. Optical impressions of the preparation and the bite registration were made. The Wilcoxon signed rank test was applied for a statistical analysis of time expended in the different design and manufacturing steps of both software versions. The chi-square test was applied for the statistical analysis of proximal and occlusal contacts.