The popularity of tooth-colored posterior restorations has increased during the last years because of a growing demand for esthetics and concern about the biocompatibility of amalgam . Applying the adhesive bonding concept, several dental ceramic systems have been used during the last decades for veneer, inlay and onlay restorations . Most ceramic materials can be bonded to the underlying conditioned tooth surface after etching with hydrofluoric acid or ammonium bifluorid, mediated by use of an enamel/dentin bonding system and a resin composite luting material. Acid etching increase surface roughness and wetting of enamel, dentin and ceramic surfaces, which promote mechanical interlocking of resin bonding systems.
Bulk fracture and loss of restoration have been reported as the main reasons of failure in short-term evaluations of inlays and onlays . Leucite-reinforced glass–ceramic inlays showed improved clinical durability compared to fired ceramics ,  and . The advantage of bonded ceramics can be expected in the extremely non-retentive coverage situation , ,  and . Traditional crown preparation techniques will in these cases occasionally result in extensive preparation and/or endodontic treatment in combination with a post and core placement in order to obtain retention. The minimal preparation for the bonded ceramic is less traumatic for the tooth, and pulp vitality can be preserved . There are few preparation design standards for the ideal dentin–enamel-bonded crowns, and Burke  showed in vitro no differences between varying degrees of tooth preparation to enhance protection to fracture. The durability of the bonded ceramic will depend on the strength of the bond between tooth, luting system and ceramic and on the inherent strength of the ceramic. The use of chemically cured resin composite cements have been suggested to obtain optimal conversion and decreased stress formation during polymerization  and .
Few studies report the longevity of dentin–enamel-bonded all-ceramic crowns also defined as “partial or full coverage restorations in which an all-ceramic is bonded to the underlying dentin and any available enamel using a resin luting material” , , ,  and . In a systematic review assessing the 5-year survival rates of single crowns, densily sintered aluminum crowns and reinforced glass–ceramic crowns (Empress) showed survival rates comparable to those seen for porcelain-fused-to-metal (PFM) crowns . The short-term results of the extensive adhesively luted coverages are promising but clinical long-term data are not available . The aim of this study was to investigate the long-term durability of these extensive dentin–enamel-bonded posterior ceramic coverages. In addition the effect of luting cement, bonding system and preparation type was studied. The hypothesis tested was that there was (1) no difference in durability for the ceramic coverage placed with different luting agents and different bonding agents, and (2) no difference in durability between vital and endodontic treated teeth.
2010. Vol. 26, no 9, 929-939 p.