48 Month Clinical Evaluation of Cercon Zirconia All Ceramic Restorations

Objectives: The purpose of this study was to evaluate Cercon zirconia all-ceramic restorations (Dentsply Prosthetics) luted with Dyract Cem Plus self-adhesive compomer cement. (Dentsply Prosthetics). Methods: 78 posterior and anterior ceramic crowns and 23 all-ceramic fixed partial dentures were inserted in 55 patients. Standard ceramic crown preparations were performed followed by conventional impressions with polyvinyl siloxane. Restorations were cemented in accordance with manufacturer's instructions. Restorations were evaluated at baseline, 6, 12, 24 and 48 months using a modified Ryge criteria. Results: The single crowns and fixed partial dentures showed very little change in all evaluation parameters during the course of the study except for several failed crowns. One patient reported transitory post-operative sensitivity which did not require additional therapy. Conclusions: The data supports that there were sufficient shades to obtain desired esthetic results, with 100% of restorations being rated alfa for shade match to Vita (Vident) shade guide. 99% of the 71 crowns recalled and 100% of the 34 fixed partial denture abutments were clinically acceptable after 12 months. Another crown failed due to bulk fracture of the veneering porcelain. At 24 months, 3 more crowns had failed with one crown fracturing and the other 2 crowns fracturing the porcelain off the zirconia substructure. At 48 months, 5 more crowns had failed; two crowns had porcelain fracture during access for endodontic therapy and another failed because the supporting core dislodged. The other two crowns exhibited porcelain fractures. All of the fixed partial denture abutment crowns were clinically acceptable at 48 months. This study was supported by Dentsply Prosthetics (York, Pa.).