Zirconia single crowns and multiple-unit FDPs-An up to 8 -year retrospective clinical study.

OBJECTIVE: The aim of this retrospective clinical study was to evaluate the survival and the occurrence of technical and biological complications of zirconia crowns and fixed dental prostheses made in the student clinic of Turku University, Finland, between April 2009 and September 2017. MATERIALS AND METHODS: Twenty-seven patients (19 female, 8 male), with zirconia crowns or FDPs, participated in the follow-up investigation. The mean age of patients was 64.6 years. Of the 40 restorations, 17 were single crowns and 23 FDPs. Twenty-seven restorations were anterior and 13 posterior. Restorations were investigated according to modified USPHS criteria. RESULTS: The survival rate of zirconia restorations after 2-8 years (average 5.7 years) of clinical use was 95%. Survival rate of single crowns was 94.2% and of FDPs 95.7%, respectively. The overall complication rate was 26% for FDPs and 5.8% for crowns. One posterior crown was lost due to a vertical root fracture and one FDP showed a framework fracture. Veneering ceramic fractures were detected in 12% of all cases (0% for crowns and 22% for FDPs). Bleeding on probing was present in 38.1% of restored teeth and 13.9% of control teeth. Embrasure space was insufficient in 52% of zirconia FDPs and 81% of these restorations showed elevated BOP values. CONCLUSIONS: Zirconia crowns and FDPs survived well in this retrospective follow-up study. Chipping of veneering ceramic and bleeding on probing were the most common complications. Thick connector areas made according to material demands resulted in insufficient embrasure spaces and inflammation of marginal gingiva.