Clinical prospective evaluation of zirconia-based three-unit posterior fixed dental prostheses: Up-to ten-year results.

OBJECTIVES: Only a few studies exist, which assess the clinical long-term behavior of all-ceramic FDPs in the posterior region. The aim of the present prospective clinical study was to evaluate the clinical performance of posterior three-unit FDPs manufactured from Y-TZP after a service period up to 10 years. METHODS: 55 patients received 59 three-unit FDPs in the posterior region of the maxilla or mandible. Abutment teeth were prepared and full-arch impressions were taken. Definitive casts were fabricated and optically scanned. Frameworks were fabricated with computer-aided design (CAD) and manufacturing (CAM) technology. Y-TZP frameworks were veneered and adhesively luted to the abutment teeth. Baseline and follow-up examinations (service time: >/= 48 months) were recorded by applying modified United States Public Health Services (USPHS) rating criteria. Cumulative survival rate was analyzed with Kaplan-Meier. Percentage of biological and technical complication was calculated. RESULTS: Fifty-three patients with 57 FDPs attended the last follow-up visit and a mean observation period of the remaining was 6.3 +/- 1.9 years was calculated. Biological complications occurred in 17.5%, technical complications in 28% of the FDPs. The 10-year cumulative survival rate amounted 85.0%. Three FDPs failed to survive, two due to a root fracture of the abutment tooth and one due to secondary caries. CONCLUSIONS: Three-unit FDPs made from Y-TZP, veneered with ceramic offer a treatment option with a high rate of chipping. However, the manufacturing processes nowadays are modified in order to avoid this complication. CLINICAL SIGNIFICANCE: The results of the present investigation suggest that three-unit Y-TZP posterior FDPs may are a possible treatment option. However, a high rate of chipping can be expected.