Outcome of zirconia partial fixed dental prostheses made by predoctoral dental students: A clinical retrospective study after 3 to 7 years of clinical service

Statement of problem. Zirconia has an established role in fixed prosthodontics, especially for single crowns. Whether it is durable enough for fixed dental prostheses (FDPs) in the long term is yet unclear. Purpose. The purpose of this retrospective study was to evaluate the outcome of FDPs made by predoctoral students after 3 to 7 years of clinical service. Material and methods. A total of 102 patients received 120 zirconia FDPs (range, 3-12 units; mean, 4.5 units) between 2007 and 2010. Materials used were Zirkonzahn Zirconia (Zirkonzahn), Nobel-Procera Zirconia (Nobel Biocare), and Prettau Zirconia (Zirkonzahn). Veneering porcelain was hand layered on Zirkonzahn Zirconia (GC Initial Zr; GC Europe) and Nobel Procera Zirconia (VITA VM 9; VITA Zahnfabrik). Prettau Zirconia was monolithic and had no veneering porcelain. Success and survival rates were calculated using Kaplan-Meier survival analysis. Ethics approval was obtained from the Ethical Committee of the Northern Ostrobothnia Hospital District (100/2013). Results. The 76 participants examined (75%) had received 88 zirconia FDPs. The mean follow-up period was 4.9 years (range, 3-7 years). The most common complication was chipping of the veneering porcelain in 13 of 88 FDPs (14.7%). The success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%. Conclusions. The success rate of the zirconia-based partial FDPs after 4.9 years was 89%, and the survival rate was 100%.