Clinical Evaluation of Zirconia-based Single Crowns: Three Years Follow Up

Objectives: The rapidly growing use of zirconia in dentistry needs more research on survival of this type of dental material. The aim of current clinical study was to evaluate clinical survival of Zirconia-core crowns during three years in a prospective manner.
Methods: This study followed-up 89 patients (36 men and 53 women aging 21-65 years) who received 118 (71 implant-supported and 47 tooth-supported) feldspathic porcelain Zirconia-based (NobelRondo™ Zirconia, Nobel Biocare®) single crowns during November 2010 and October 2011 in Prosthodontics Clinic of Mashhad University of Medical Sciences. Crowns were evaluated by a prosthodontist 6, 12, 24, and 36 months after cementation using California Dental Association (CDA) criteria. Data were reported descriptively.
Results: Total of 81 patients with number of 106 zirconia-based single crowns successfully completed the three year period follow-up. In total 15(14%) crowns/abutments experienced some kind of complication. One tooth because of root fracture and one because of endodontic failure were extracted. Nine (8.4%) crowns faced fracture of the veneering porcelain while 5(4.7%) of them were rebuilt because of retention loss and secondary caries. Among the crowns, 91(85.8%) had no or slight alteration in their prosthesis due to CDA evaluation criteria which considered successful.

Conclusions: Porcelain-veneered Zirconia crowns revealed good clinical performance and patients were satisfied with their aesthetic features. In longer follow-up periods more investigations are encouraged to compare FDPs and single zirconia-based crowns.