Shear bond strength and failure modes of composite to dentin under different light-curing conditions

Abstract

This study aimed to examine the effects of different light-curing modes on the immediate shear bond strength (SBS) of different composite resin types to dentin using universal adhesive. Human teeth were extracted and sectioned to obtain flat dentin slices. The universal adhesive was applied in total-etch mode. Conventional and bulkfill composites were used to create cylindric build-ups. Full power and Ramp mode were used to light-cure the adhesive and composite resin. SBS test was performed in a universal testing machine, and failure modes were determined via scanning electron microscopy (SEM). Two-way ANOVA and Student t-test were used to analyze statistical data. Significantly higher SBS was obtained when bulkfill composite was used compared to the conventional one ( p < .001). The difference between Full power and Ramp curing mode was insignificant ( p = .4). Mixed failure was the predominant type. Low SBS resulted in adhesive failure, while high SBS resulted in cohesive failure. Shear bond strength was not curing-dependent but rather material-dependent. Ramped curing does not contribute to higher bond strength. Bulkfill composite seems to be more favourable in terms of bond strength.