BOND STRENGTH, INTERFACIAL CHARACTERIZATION, AND FRACTURE SURFACE-ANALYSIS FOR A NEW STRESS-BREAKING BONDING AGENT

Three commercial dentin bonding systems were analyzed by tensile bond testing, area analysis of fractured surfaces, and SEM analysis of the tooth-resin interfaces. Tensile bond strengths in megapascals(SD) were Tenure-Marathon V ([T-M]; 8.86[3.02]), new system with low-viscosity resin ([K-LVR-P]; 6.50[2.011]), and new system without low-viscosity r esin ([K-P] = 7.28[1.75]), which were significantly greater than Scotc h-bond 2-P50 ([SB-P50]; 3.96[1.02]). Gaps that ranged up to 5.6 mu m ( mean for the group) were observed around most of the restorations at d entin surfaces and less so at enamel surfaces, where some of the resto rations remained free of gaps. The gaps near the dentin margin were si gnificantly smaller for K-LVR-P than for SB-P50. The tensile test reve aled mixed failure modes in all systems, and in the cross sections of class V restorations, the gaps were confined to the dentin-resin junct ion.