Marginal adaptation of nine commercial intermediate resins

The bonding efficacy of nine commercially available intermediate resins was examined by measuring the maximum contraction gap of a light-activated composite in a cylindrical cavity of human dentin. With only one exception, the marginal adaptation of the composite improved significantly when the intermediate resins were combined with an experimental dentin cleaning system of the neutralized 0.5 mol/L EDTA and a dentin primer composed of a 35% aqueous solution of either hydroxyethyl methacrylate (HEMA) or glyceryl methacrylate (GM). Complete marginal adaptation was obtained with four tested materials when dentin was pre-treated with EDTA and GM.