Surface free-energy measurements as indicators of the bonding characteristics of single-step self-etching adhesives

This study examined the surface free-energy of dentin treated with the single-step self-etching adhesives Bond Force, Clearfil tri-S Bond, and G-Bond Plus. The labial dentin surfaces of bovine mandibular incisors were wet ground with #180-, #600-, and #2,000-grit silicon carbide paper. The adhesives were applied to the ground dentin, and then rinsed with acetone and distilled water. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the adhesive-treated dentin. The surface free-energies of the samples treated with the G-Bond Plus and Clearfil tri-S Bond adhesives increased as the surface roughness decreased. No significant differences in the surface free-energy were found for the samples treated with the Bond Force adhesive, regardless of the surface roughness. These results indicated that dentin surfaces treated with adhesives did not promote a higher surface-energy state, and that differences in the components of surface energy were apparent for the adhesives tested.