Bond strengths of resin-modified glass ionomers and polyacid-modified resin composites to dentin.

PURPOSE

To measure the shear bond strength of two resin-modified glass ionomers (Vitremer and Fuji II LC) and two polyacid-modified resin composites (Compoglass and Dyract) when applied to dry dentin, dentin supplied with water pressure from the pulp, and after thermocycling.

MATERIALS AND METHODS

Ninety six extracted third molars were used. The root portion was removed just below the cemento-enamel junction and the occlusal enamel was removed from the crown segment. An artificial root portion was made in Plexiglas, cemented to the crown segment and connected to a 36 cm. height water column. The tested materials were applied to the surface of dry dentin, dentin supplied with water pressure from the pulp, and after thermocycling. Shear bond strength was measured for the bonded specimens using an Instron at a crosshead speed of 0.5 mm/minute.

RESULTS

There were no significant differences in bond strengths between Fuji II LC, Compoglass, and Dyract, which were significantly greater than that of Vitremer. The bond strengths of all materials were slightly increased or not affected by the presence of water pressure from the pulp. After thermocycling, the bond strengths of Fuji II LC, Compoglass, and Dyract were not significantly affected whereas those of Vitremer were significantly decreased.