six systems ( one polycarboxylate , one polymethyl methacrylate , one unfilled bis-gma resin , two combinations of methyl cyanoacrylate and polymethyl methacrylate , and one combination of unfilled bis-gma and filled composite resin ) were evaluated for in vitro retention to acid-etched human enamel .
C0053749
bis-gma
C0009570
composite