Ten-year survival and chipping rates and clinical quality grading of zirconia-based fixed dental prostheses

Objectives To prospectively evaluate the clinical long-term outcome of 3- to 6-unit fixed dental prostheses (FDPs) made of hot isostatic pressed (HIP) zirconia frameworks, veneered with a synthetic sintering glass-ceramic. Materials and methods A total of 27 different restorations were cemented in 21 patients. FDPs were examined with regard to biological and technical complications/failures. Additionally, clinical quality was assessed based on (i) the California Dental Association (CDA) criteria, (ii) the patient's viewpoint according to Hickel, and (iii) periodontal parameters. Descriptive statistics were computed. The Kaplan-Meier estimator was used for the survival and chipping-free rates. Wilcoxon signed ranks test (ordinal/continuous data) or the McNemar test (binary data) was used to describe the periodontal outcome of abutment teeth versus that of the respective control teeth. Results After a mean observation period of 10.0 +/- 2.1 years, the dataset comprised 15 patients with 20 (mainly posterior) FDPs. The 10-year survival rate and 10-year chipping-free rate were 95.0% (CI 86.0-100%) and 78.8% (CI 62.2-99.7%), respectively. Evaluation based on the CDA criteria yielded satisfactory (excellent or acceptable) results for all categories. This was also confirmed by the high level of patient satisfaction. The periodontal health of tissues adjacent to the study teeth was clinically acceptable, but inferior to the ones of control teeth. Conclusions FDPs made from CAD/CAM-fabricated HIP zirconia ceramic frameworks have a favorable survival rate. However, because damage to the surface texture showed a disproportionate increase after long-term usage, additional long-term studies are required.