SHEAR BOND STRENGTH OF CHEMICAL AND LIGHT-CURED GLASS-IONOMER CEMENTSBONDED TO RESIN COMPOSITES

A bond between glass ionomer cements (GIC) and resin composites is des irable for the success of the 'sandwich' restoration. Chemically cured glass ionomer cements have been the traditional materials used in thi s technique since its development, but etching the GIC was necessary t o obtain a bond to the composite facing. Producing a very smooth GIC s urface has aided in better determining the magnitude of the chemical b ond between glass ionomers and resin composites. Shear testing of bond ed specimens has revealed that chemical bonding is minimal (0.21 MPa) in conventional glass ionomers, but does exist (4.92 MPa) between GIC and resin composite regardless of the filler content (microfilled vs h ybrid) of the composite. Thermal stressing affects the bond to resin-m odified glass ionomers, but has no significant effect on self-cured ce ments. Of all combinations tested, Vitremer/Scotchbond/Silux Plus show ed the highest mean shear bond strength. Based on the clinical need fo r an adhesive bond between GIC liner/base and resin composite, the res in-modified glass ionomer would appear to be the material of choice.