Implant-Supported Extra-Orally Cemented Monolithic Zirconia Crowns: A Prospective Controlled Clinical Study up to 18 Months in Function.

This study evaluated the clinical performance of implant supported, extra-orally cemented, monolithic zirconia crowns after a follow-up to 18 months. Thirty-one patients with 50 posterior dental implants were consecutively selected for this study. A total of 50 crowns were cemented onto titanium abutments extra-orally and then screwed to the implants with the required torque intra-orally. The patients were followed at 12 months and 18 months after placement of restorations. During the follow-up period, all restorations were evaluated according to following technical parameters: implant failure, crown fracture, screw loosening, loss of retention due to decementation, fracture of antagonist tooth or restoration. Data were analyzed using Kaplan Meier method. One implant and its corresponding crown was lost during the follow-up period, yielding a 18 months survival rate of 98%. During the study, 2 complication events were observed, including one screw loosening and one veneering porcelain chipping in an antagonist bilayered zirconia restoration. The overall success rate of the observed prosthesis was 96%. According to the results of this study, the extra-orally cemented, monolithic zirconia crowns resulted in a favorable short-term outcome for posterior implant supported restorations within this short observation time.