Shear bond strength of chemical and light-cured glass ionomer cements bonded to resin composites.

A bond between glass ionomer cements (GIC) and resin composites is desirable for the success of the 'sandwich' restoration. Chemically cured glass ionomer cements have been the traditional materials used in this technique since its development, but etching the GIC was necessary to obtain a bond to the composite facing. Producing a very smooth GIC surface has aided in better determining the magnitude of the chemical bond between glass ionomers and resin composites. Shear testing of bonded 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 hybrid) of the composite. Thermal stressing affects the bond to resin-modified glass ionomers, but has no significant effect on self-cured cements. Of all combinations tested. Vitremer/Scotchbond/Silux Plus showed the highest mean shear bond strength. Based on the clinical need for an adhesive bond between GIC liner/base and resin composite, the resin-modified glass ionomer would appear to be the material of choice.