Effect of the self etching dentin primers on the bonding efficacy of a dentin adhesive

The efficacy of marketed and experimental self etching dentin primers which contained dicarboxylic acids or their esterified salts diluted in 35% hydroxyethylmethacrylate (HEMA) solution were studied by measuring the wall-to-wall polymerization contraction of the light curing composite in the cylindrical dentin cavity and the tensile bond strength to the flat dentin surface. In both of the measurements, a marketed dentin bonding agent and resin monomer was applied after the treatment with experimental primers and a marketed primer, respectively. It was revealed that two experimental primers composed of the methacryloxyethyl-succinate or methacryloxyethyl-phthalate and HEMA, exhibited a remarkable effect on the bonding efficacy of a dentin adhesive employed in this study. A marketed primer which contained maleic acid and HEMA could not improve the bonding between the resin and dentin cavity wall although a significantly high bonding strength (11.9 +/- 5.7 MPa) was obtained after 24 hours.