FRACTURE STRENGTH OF FULL-CONTOURED CERAMIC CROWNS AND PORCELAIN-VENEERED CROWNS OF CERAMIC COPINGS

This in vitro study compared the fracture strength of Dicor ceramic crowns with a 1 mm axial wall thickness and a 2 mm occlusal thickness with Dicor copings veneered with Vitadur-N or Dicor-Plus porcelain to create similar contours. Tooth preparations for complete crowns were made on human molars with a 10-degree total convergence and a 1 mm shoulder. The artificial crowns were internally etched, given an application of silane, and cemented with a dual-cured resinous cement. After thermocycling, each sample was loaded to failure with a vertical load on the occlusal surf ace. There were no significant differences in fracture strength between full-contour Dicor crowns and crowns of copings veneered with either Vitadur-N or Dicor-Plus porcelain.