The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic repairs depends on the quality and durability of the bond between the resin and ceramic. The quality of this bond will depend on the bonding mechanisms that are controlled, in part, by the surface treatment that promotes micromechanical and chemical bonding to the substrate. The objective of this work was to examine the correlation of interfacial toughness (K(A)) with fracture surface morphological parameters of the resin-ceramic systems as a function of ceramic surface treatment. This analysis was designed to identify mechanisms that promoted adhesion of these resin-ceramic systems and an appropriate bond test method to yield relevant adhesion performance data. The rationale used in this work indicates that the quality of the bond should not be assessed based on bond strength data alone. In addition, the mode of failure and fractographic analyses should be used to provide important information leading to predictions of clinical performance limits, which is the ultimate test for any adhesive system. (C) Koninklijke Brill NV, Leiden, 2009