Bond strength evaluation of composite resin bonded to glass ionomer cements after different periods of setting

This study investigated the time elapsed after setting of glass ionomer cements on the bond strength to composite resin restorations. Bovine incisors received cavity preparations on the buccal surface (6 mm×6 mm×2 mm) and the specimens were tested according to cement type (conventional and resin-modified) and time elapsed before performing the restorations: GC10m: conventional glass ionomer cement and 10 min time elapsed after setting; GC24h: conventional cement and 24 h after setting; GC7d: conventional cement and 7 days after setting; GRM10m: resin-modified glass ionomer cement and 10 min after setting; GRM24h: resin-modified cement and 24 h after setting; and GRM7d: resin-modified cement and 7 days after setting. Specimens were subjected to micro-shear testing and the data were analyzed by Analysis of Variance and Tukey′s test (p=0.05). Bond strength of restorations performed on conventional cement after 10 min of time elapsed presented the lowest mean values and differed statistically from values at 24 h and 7 days. Resin-modified cement after 24 h presented the highest mean values and differed statistically from values at 10 min and 7 days. The time elapsed after setting of glass ionomer cement may interfere in the bond strength to composite restorations.