Abstract
The present study investigated the effect of treating dentin with 2-hydroxyethyl methacrylate(HEMA)prior to application of a photocure bonding agent.The photocure bonding agent was composed of 0.5% camphorquinone(CQ)as a photosensitizer, 0.5% N-phenyl-glycine(NPG)as a reducing agent, 5.0% 2-methacryroyloxyethyl phenyl hydrogen phosphate(Phenyl-P)as an adhesion promoting monomer and 94.0% triethyleneglycol dimethacrylate(TEGDMA)as a base monomer.Bovine dentin samples were ground with 600-grid Carbimet paper discs(Buehler, USA), and demineralized with either aqueous solutions of 1, 5, 10, 20, 40 or 65% phosphoric acid.Improvement of bond strength depended on whether dentin treated with HEMA was rinsed.Without rinsing, improvement of bond strength was achieved even during contact of collagen with HEMA for 1min only.The effect of the 1min-HEMA treatment disappeared with rinsing on the tensile bond test.But even when rinsed, with HEMA treatment for 60min, improved bond strengths were achieved.When HEMA application followed phosphoric acid etching, a hybrid layer was demonstrated on SEM, and the bond strength increased to 6-7MPa.
