Universal adhesive application to contaminated/non-contaminated dentin with three different protocols: An in vitro shear bond strength and SEM analysis.

This study aimed to comparatively evaluate the shear bond strength (SBS) of a universal adhesive to contaminated/non-contaminated dentin when applied with three different protocols. One-hundred-eighty dentin samples were divided randomly into 12 groups (n=15). The groups were created by combining four dentin contamination conditions (non-contaminated or contaminated with blood, hemostatic, or blood+hemostatic) with three application protocols for Single Bond Universal (no-preconditioning or preconditioning with the 35% phosphoric or 1% gallic acid). Following thermal cycling, the SBS test was performed. Data were analyzed using two-way-ANOVA and Tukey's HSD (p<0.05). Dentin surfaces subjected to phosphoric acid, gallic acid, or hemostatic were examined using scanning electron microscope (SEM) analysis. SBS results were influenced by both the dentin contamination (p<0.001) and application protocol (p<0.001). A significant interaction was found between the two factors (p=0.005). The highest bonding performance to contaminated dentin -at all contamination conditions- was achieved with the gallic acid preconditioning.