Ten-year survival and complication rates of lithium-disilicate (Empress 2) tooth-supported crowns, implant-supported crowns, and fixed dental prostheses

Objectives: To prospectively evaluate the clinical long-term outcome of tooth-supported crowns (SCs), implant-supported crowns (ISCs), and fixed dental prostheses (FDPs) made of a lithium-disilicate glass ceramic framework material (IPS Empress 2). Materials and methods: Between 1997 and 1999, a total of 184 restorations (106 SCs, 32 ISCs, 33 FDPs, and 13 diverse restorations) were placed in 73 patients. Kaplan-Meier estimation was applied for survival and chipping-free rates. Inter-group comparison of both rates was realized by a log rank test and a 2 x 2 contingency table. Also, SCs and FDPs were compared regarding adhesive vs. conventional cementation, and anterior vs. posterior positioning, for impact on survival. Results: Due to 14 dropouts (34 restorations) and reasonable exclusion of 19 other restorations, the final dataset included: i) 87 SCs [37 patients, mean observation time 11.4 (+/- 3.8) years]; ii) 17 ISCs [12 patients, mean observation time 13.3 (+/- 2.3) years; and iii) 27 FDPs [19 patients, mean observation time 8.9 (+/- 5.4) years]. The 10-year survival rate/chipping-free rate for SCs were 86.1%/83.4%, for ISCs 93.8%/94.1%, and for FDPs were 51.9%/90.8%. Both ISCs and SCs had a significantly higher survival than FDPs (ISCs vs. FDPs: both tests p = 0.001; SCs vs. FDPs: p = 0.001 and p = 0.005). Differences in the chipping-free rates did not reach significance. Also, neither the cementation mode nor positioning of the restoration had an impact on survival. Conclusions: SCs had a slightly lower outcome than can generally be expected from single crowns. In contrast, ICSs had a favorable outcome and the FDPs predominantly failed. Clinical significance: The practitioner's choice of dental materials is based (at best) on long-term experience. The present 10-year results are based on comprehensive data analyses and show the high potential of lithium-disilicate as a reliable material, especially for single-unit restoration. (C) 2016 Elsevier Ltd. All rights reserved.