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 cr owns with a 1 mm axial wall thickness and a 2 mm occlusal thickness wi th Dicor copings veneered with Vitadur-N or Dicor-Plus porcelain to cr eate similar contours. Tooth preparations for complete crowns were mad e on human molars with a 10-degree total convergence and a 1 mm should er. The artificial crowns were internally etched, given an application of silane, and cemented with a dual-cured resinous cement. After ther mocycling, each sample was loaded to failure with a vertical load on t he occlusal surf ace. There were no significant differences in fractur e strength between full-contour Dicor crowns and crowns of copings ven eered with either Vitadur-N or Dicor-Plus porcelain.