Survival Rates of Zirconia Crowns in a Specialist Private Practice

Purpose: The aim of this study was to evaluate the survival rates of zirconia crowns performed in a specialist private practice, as well as to determine the risk factors for failure of these zirconia restorations. Materials and Methods: 112 patients who were treated with low-fusing porcelain-veneered zirconia restorations (single crowns, fixed partial dentures and implants) were included in this study. A total of 762 restorations were evaluated during follow-up visits from July 2008 to February 2011. Evaluation criteria included anatomic form, colour, surface integrity and marginal fit. Results: 69% of the zirconia restorations were single crowns and fixed partial dentures. 31% were implant restorations. 37% of them were placed in the anterior teeth, 29% were premolars and 33% were molars. 15 (1.97%) cases of failures in 8 patients were recorded, which included 9 (1.18%) cases of fracture of veneering porcelain, 1 (0.13%) case of a veneering porcelain crack line, 3 (0.39%) cases of zirconia core fracture, 1 (0.13%) case of crown dislodgement and 1 (0.13%) case of implant loosening. Conclusions: Low-fusing porcelain-veneered zirconia restorations showed excellent clinical outcome with a survival rate of 98.03% over a cumulative follow-up period of 31 months. There was no observed pattern of failure of the prostheses in terms of location. The range of failures occurred within a time frame of 2-18 months post-cementation with a mean of 8.67 months. Majority of failures occurred in complex restorative cases involving more than 10 units.