Solvent type influences bond strength to air or blot-dried dentin

BACKGROUND: Air-drying of etched and rinsed dentin surface may force the exposed collagen fibrils to collapse. Blot-drying is an alternative method to wipe the excess water from the dentin surface without compromising the monomer penetration. Contemporary total etch adhesives contain ethanol/water or acetone as solvent in which resin monomers are dissolved. Solvent type of the adhesive system has an important role in bonding to dentin. An adhesive containing tertiary butanol as an alternative solvent has been in the market. Purpose of this study is to determine the shear bond strengths of three total-etch adhesives with different solvents (acetone, ethanol or tertiary butanol) applied to air or blot dried moist dentin. METHODS: Sixty extracted non-carious human third molars were divided into three main groups according to solvent content of the adhesives [acetone based - One Step (OS, Bisco, IL, USA); ethanol/water based - Optibond Solo Plus (OB, Kerr, CA, USA); and tertiary butanol based - XP Bond (XP, Caulk/Dentsply, DE, USA)]. Each main group was divided into two groups according to drying methods (blot or air) (n = 10). Shear bond strengths (SBS) were measured. Data were analyzed by Student’s t test and Tukey HSD test (p < 0,05). RESULTS: XP showed highest SBS values in both drying methods applied (p < 0.05). Drying method did not influence the SBS in OS and OB (p > 0.05). XP-blot produced significantly higher SBS than XP-air (p < 0.05). CONCLUSIONS: Tertiary butanol based adhesive showed higher bond strength values than ethanol or acetone based adhesives. Blot drying of dentin improved the bond strength values of tertiary butanol based adhesive. Further research is necessary to determine in vivo and in vitro performance of tertiary butanol based adhesives.