Combination of EDTA conditioner and Phenyl-P/HEMA self-etching primer for bonding to dentin

Objectives: The purpose of this study was to examine a new bonding system, combining an ethylenediaminetetraacetic acid (EDTA) conditioner and the 2-methacryloyloxyethyl phenyl phosphoric acid (Phenyl-P)/2-hydroxyethyl methacrylate (HEMA) self-etching primer with a dumbbell-shaped specimen for tensile test. Methods: Bovine dentin was prepared with a 180-grit paper, conditioned with EDTA, primed with Phenyl-P/HEMA and applied with a light-cured bonding agent, then trimmed to the dumbbell-shaped specimen. After storage in water at 37°C for one day, the tensile bond strength was measured and the hybridization was evaluated by scanning electron microscopy (SEM). Results: When the demineralized dentin with EDTA was primed with 1 wt% Phenyl-P in 30 wt% aqueous HEMA for 10 s, the highest tensile bond strength (22 MPa) was obtained. The SEM views showed that the fractured surface after the tensile test was due to cohesive failure in the cured resin and the 1 μm-hybridized dentin was identified. When the concentration of Phenyl-P and the priming period were increased, tensile bond strength significantly decreased and adhesive failure appeared on the fractured surface. Significance: Combining the EDTA conditioner and Phenyl-P/HEMA primer afforded high-quality hybridization and good bond strength. This bonding system was promising for bonding resin to human dentin.