Shear bond strength of four core materials to dentin bonded with light-cured or dual-cured adhesive

To measure and compare the shear bond strength of four core materials to dentin bonded with one adhesive (Prime and Bond NT) that was either light-cured or dual-cured.

The dentin of 80 freshly extracted molars was exposed using a series of abrasive disks. The teeth were divided into eight equal groups, etched with phosphoric acid for 15 seconds and rinsed. Dentin was dried to a moist surface. On 40 teeth, Prime and Bond NT was applied and light-cured for 30 seconds. On 40 teeth, Prime and Bond NT was mixed with the self-cure additive, which was applied to the dentin, and light-cured for 20 seconds. The core materials were then placed following manufacturers' directions onto the cured adhesive. The core material was light-cured, when it was necessary, for 60 seconds and stored for 24 hours in water at room temperature. The specimens were loaded in shear in the Instron until failure at a 5 mm/minute crosshead speed. Data were compared using two factor ANOVA and Tukey's HSD test (P = .05).

Both curing mode and core material showed a significant difference. A significant difference between mean shear bond strength for dual and light cured was observed only in CompCore (P = 0.0002). There was no statistical difference when Prime and Bond NT dual-cured was used with chemical- or dual-cured materials.