Abstract
Purpose: To evaluate the effects of oxygen inhibition of universal adhesive on dentin bond durability and interfacial characteristics. Methods: The three universal adhesives used were Scotchbond Universal Adhesive, Prime & Bond Elect, and G-Premio Bond. Shear bond strength (SBS) and shear fatigue strength (SFS) of resin composite bonded to adhesive with and without an oxygen inhibited layer (OIL) on dentin using total-etch and self-etch modes were determined. Surface free energy (SFE) and SFE parameters of cured adhesive with and without an OIL on dentin using total-etch and self-etch modes were also measured by the sessile drop method. Results: The presence of an OIL in universal adhesives promoted higher SBS and SFS regardless of etching mode. In addition, regardless of adhesive type and etching modes, the specimens with an OIL showed a higher ratio of SFS/SBS than those without an OIL. Further, the SFEs, especially total SFE, polarity force and hydrogen bonding force, of cured adhesives with an OIL were significantly higher than those without an OIL.