Clinical Evaluation of Two All-ceramic Crown Systems Luted with Different Luting Agents

Objectives: The aim of this study was to evaluate the clinical performance of two different all-ceramic crown systems luted with two different luting agents up to 5.5 years after placement. Methods: 98 patients, who needed full-crowns in the posterior teeth, were randomly supplied with leucite-reinforced glass-ceramic crowns (Empress (E)) or with alumina reinforced all-ceramic crowns (In-Ceram (I)), either luted with zinc phosphate cement (Tenet (T)) or with dual-curing composite (Variolink (V)). 70 out of these 98 patients were examined according to modified USPHS criteria up to 5.5 years after placement. Kaplan-Meier survival estimates were generated for each treatment group (95% level of confidence). Differences in survival were evaluated with the log-rank chi-square test (alpha=.05). Results: 52 of 70 all-ceramic crowns were rated Alpha or Bravo. Worst ratings (Charlie or Delta) of further 18 restorations are displayed in Tab. 1. The 5-year survival rates estimated by Kaplan-Meier method were 85% in group E/T, 100% in group E/V, 100% in group I/T and 93% in group I/V, respectively, regarding the ceramic cracking or chipping. There was no significant difference in survival among the 4 treatment categories (P>0.05). Conclusions: Empress as well as In-Ceram crowns, either luted with zinc phosphate cement or with dual-curing resin composite are clinically acceptable restorations in posterior teeth.