This study investigated the effect of antimicrobial agents on the antibacterial potential of a one-step dental adhesive. Zinc silicate microparticles (ZnSi), silver microparticles (Ag), or essential oil of tea tree (terpinen-4-ol, Tr) were added at 0.5 wt% or 1 wt%. Additional analysis included pH, degree of C=C conversion (DC), translucency parameter (TP), water sorption/solubility (WSR/SL), morphology of bonded interfaces, and dentin microtensile bond strengths (µTBS) after 24 h or 6 months. Antibacterial potential was assessed using a microcosm biofilm model. Data were statistically analyzed at α=0.05. DC, WSR/SL, and bonding morphology were not affected by antimicrobial incorporation. ZnSi and Ag increased pH and improved immediate µTBS, generating more stable dentin bonds after 6 months. Tr showed the poorest results for µTBS. Ag 1% was the adhesive with lower TP. In general the best antibiofouling results were observed for Ag 0.5 wt%, although all antibacterial agents showed some antibiofouling effect.
