Technical Outcome of All-ceramic CAD-CAM Restorations: 10-year Follow-up Study

Objectives: There are hardly any independent studies documenting the technical outcome of Cad-Cam generated restorations as manufactured by out-lab industrial centres. New technologies inherently restrict reporting to small numbers and short follow-up times. Aim of this paper is to report on the technical outcome of a large series of Cad-Cam generated full ceramic restorations for single teeth and fixed partial dental prostheses (FPDP). Materials & Methods: 29.775 Cad-Cam generated single full-ceramic copings and 705 FPDP of one particular brand (Procera™, Göteborg, Sweden) scanned and veneered at one dental lab (TTL Sips Oosterhout, The Netherlands) over a 10 year period were included. Coping data were collected at lab intake and when the veneered restorations were delivered and followed-up at the dental office. A follow-up of up to 10 years for any event that needed any intervention by the lab was performed. Estimation and comparison of failure probabilities was performed within a competing risks framework. α was set at 5%. Results: Of the 29.775 single copings, 1.84% were rated a failure before delivery to the dentist. The cumulative fracture failure rate of single Al2O3- vs. (n=21.777) ZrO2-restorations (n=6.576) at year 6 amounted to 2.66 and 5.01% respectively (p=0.003). Of the 705 full ceramic FPDP frames, 8.23% were rated a failure before delivery to the dentist. The cumulative fracture failure rate of 3- and 4-unit porcelain veneered ZrO2 FPDPs (n=449) at year 4 amounted to 0.76% and 0% respectively (p=0.1). When combining single restorations with those of FPDPs the cumulative porcelain veneering fracture rates of Al2O3 (21.797) vs. ZrO2-restorations (n=8.678) at year 6 was 0.24 and 0.49% respectively (p=0.00003). Conclusions: Current evidence suggests that all-ceramic cad-cam generated restorations have an acceptable clinical longevity that accompanies their long-lasting aesthetic advantages. Nevertheless, chipping of the veneering ceramic on zirconia restorations was doubled compared to alumina.