COMPARATIVE SHEAR BOND STRENGTH OF SOME ORTHODONTIC BONDING RESINS TOENAMEL

The aim of this study was to compare the in vitro bond strength, to bo vine enamel measured in shear, of the orthodontic adhesives Lee Insta- bond (LiB), Rely-a-Bond (RaB), Right-on (Re), Concise precoating metho d (Cc), Concise mixed method (Cab), Super-C (Sc), and Orthon (Or), and of the glass ionomer cement Ketac-Cem (KC). The fracture surfaces aft er debonding were also examined in order to determine the sites of fai lure. The results indicate that there is a significant difference betw een the shear bond strength obtained with the different adhesives so t hat the mean shear bond strength decreases in the order {Ro similar to Cab similar to Sc} > {LiB similar to RaB similar to Cc} > Or > KC. Mo reover, for Cab and Sc it was found that the shear bond strength varie s depending on the location on the bovine tooth. The failure site was essentially at the resin-bracket interface, except for Concise, where only 50 per cent of the cases failed at the resin-bracket interface.