Objectives : The purpose of this study was to investigate the effect of wet bonding and colloidal platinum nanoparticles (CPN, Apt, LTD) on the dentin bond strength of one-step bonding systems under four different bonding strategy groups: control, wet, etch-wet, etch-CPN-wet.
Materials and methods : Three one-step bonding systems used in this study were: Easy One (EO; 3 M, US), Bond Force (BF; Tokuyama, Japan), Beauti Bond (BB; Shofu, Japan). Twenty-four human molars were used in this study. The flat ground surfaces of dentin were polished with 600-grit silicon carbide paper under running water. Group1 (control): the dentin surfaces were bonded according to the manufacturers’ instructions of each one-step bonding system. Group2 (wet): the dentin surfaces were bonded under visible wet condition. Group3 (etch-wet): the dentin surfaces were treated with 35% phosphoric acid for 15 s, followed by rinsing with water for 5 s and bonded under visible wet condition. Group4 (etch-CPN-wet): the dentin surfaces were treated with 35% phosphoric acid for 15 s, followed by rinsing with water for 5 s. After air drying, they were treated with 10% CPN for 30 s which followed by rinsing with water for 20 s. Resin composite was built up to approximately 5 mm height on flat surfaces of dentin. They were sectioned into beam specimens (cross-sectional area 1 mm 2 ) after storage in 37 °C water for 24 h. The specimens were subjected to MTBS test and the resin dentin interfaces were observed by SEM (Hitachi S-4000). The Games-Howell test was used for the statistical analysis of the MTBS ( p < 0.05; n = 15).