Bonding of a composite restorative material to etched glass ionomer cement*

The tensile bond strengths of a composite restorative material to phosphoric acid etched restorative glass ionomer cement were examined as a function of cement brand, time after mixing at which etching was performed, thickness of film on enamel and dentine and extent of exposure to water during cement maturation. Optimum bond strengths were obtained with mature cements isolated from water during maturation. Bond strengths were similar to or greater than tensile strengths of cements and many currently available dentine bonding agents for composites. Bonding to etched cement occurs by micromechanical interlocking and the zone of bond failure in tension was in the surface layer of the cement.