comparative evaluation of microtensile bond strength of three adhesive systems

Objectives: the aim of this study was to assess the microtensile bond strength of three universal adhesives to dentin and enamel. materials and methods: sixty extracted human third molar teeth were chosen and divided into six groups regarding the adhesive (g-premio bond, clearfil s3 bond or single bond) and tooth surface. all the applied bonding agents were universal adhesives. the teeth were polished and the adhesives were applied; then the teeth were restored with composite resin. the samples were mounted in acrylic resin and sectioned. the specimens were subjected to a universal testing machine and the microtensile bond strength was measured. the failure mode of each specimen was determined under a stereomicroscope. data were analyzed using two-way anova (α=0.05). results: the microtensile bond strength of g-premio bond to enamel and dentin was 11.79±8.27 and 17.55±9.47 mpa, respectively which was not significantly different from the values in single bond group (15.59±10.66 and 17.19±10.09 mpa to enamel and dentin, respectively; p>0.05). however, the values for clearfil s3 bond were 7.11±4.23 and 7.88±8.83 mpa to enamel and dentin, respectively, which were significantly lower than the values for g-premio bond (p<0.05). scanning electron microscopic (sem) images showed that the adhesive failure was dominant in both enamel and dentin groups and in all adhesive systems. conclusion: g-premio bond and single bond provided higher microtensile bond strength compared with clearfil s3 bond. universal adhesives with their acceptable performance can be applied in self-etch mode on both enamel and dentin.