Five-Year Clinical Evaluation of Empress 2 Restorations

Objectives: The purpose of this prospective study was to evaluate the clinical performance of a lithium-disilicate substructure glass-ceramic (IPS Empress 2 (E2), IvoclarVivadent (IV)) for crowns and bridges. Methods: Patients with severe parafunction, periodontitis or poor oral hygiene were excluded from the study. From December 1997 to June 1999, a total of 204 E2- restorations (155 crowns and 49 bridges) have been placed in 72 patients. Clinical treatment was performed by five trained clinicians following a fixed protocol. All substructures were fabricated and veneered by the corresponding fluor-apatite glass-ceramic. For placement either a dual-curing resin (Syntac/Variolink II, IV) or a glass-ionomer (Ketac Cem Maxicap, 3M ESPE) cement was used. To date (7/2005) 137 crowns and 46 bridges were evaluated. Adhesive placement was employed for 100 and conventional cementation for 81 restorations. The mean observation period was 60 months (± 21.5). Results: 19 absolute failures were recorded, the majority (13) as fractures in the bridge group. Ten of the fractured bridges were placed in a location, excluded by manufacturer`s guidelines. Eight absolute failures were not caused by insufficient framework strength. Relative failures occurred mainly as minor and extended chippings of the veneering material (18). Conclusions: Five-year clinical evaluation demonstrated, that the clinical and technical guidelines for E2 must be strictly followed to achieve acceptable clinical performance. Further research has to be undertaken to analyse factors causing chippings with the first generation of E2 veneering material. This study was supported by Ivoclar Vivadent AG, Liechtenstein.