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

ObjectivesTo 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 methodsBetween 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 × 2 contingency table. Also, SCs and FDPs were compared regarding adhesive vs. conventional cementation, and anterior vs. posterior positioning, for impact on survival.ResultsDue 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.ConclusionsSCs 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 significanceThe 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.