Prospective study of zirconia-based restorations: 3-year clinical results

Objectives: To evaluate fixed dental prostheses (FDPs) and single crowns made of zirconia substructures veneered with new fluorapatite veneering porcelain. Method and Materials: Thirty-eight patients received 18 FDPs and 50 single crowns. Zirconia substructures were fabricated by a CAD/CAM system and veneered using the powder buildup technique. All restorations were cemented with glass ionomer. Baseline evaluation was performed 2 weeks after cementation with recall examinations at 12, 24, and 36 months by calibrated investigators. SEM was performed on replicas of all restorations. Survival probabilities according to Kaplan-Meier were calculated. Results: The mean service time was 35 (± 14) months. After 3 years of clinical service, three biologic and five technical failures were recorded. All failures occurred in the FDP group. One FDP was removed after biologic failure of one abutment tooth. The Kaplan-Meier survival probability was 88.2% after 35 months for all types of failures and 98.5% concerning restorations in service. The type of restoration showed significant influence on the survival probability (P .001, log-rank test). No influence on gingival parameters from the restorations was observed compared to control teeth. Conclusions: Zirconia substructures veneered with fluorapatite veneering porcelain seem to be a reliable treatment option. More research has to be conducted to investigate differences between single crowns and FDPs. Keywords: CAD/CAM, fixed dental prosthesis, fluorapatite veneering porcelain, porcelain chipping, single crown, zirconia