effect of water storage on the micro-shear bond strength of two self-etch adhesives to enamel and dentin

objective: this study evaluated the influence of storage time on micro-shear bond strength of two self-etching materials to enamel and dentin. materials and methods: human third molar teeth were sectioned to 1.5 mm thick beams and randomly divided into 2 groups. in group i, se bond and in group ii, tri-s bond was used to bond a composite rod (ap-x) to each treated surface. specimens were prepared according to manufacturer instructions. each group was further divided into three subgroups according to water storage time; 1 day, 6 and 12 months. micro-shear bond strengths were determined under a crosshead speed of 1mm/min using a universal testing machine and expressed in mpa. data was statistically analyzed by anova and dunnett post hoc test. results: micro-shear bond strength of two adhesives to enamel and dentin showed a slight but not significant decrease over time (p>0.5). after one day, the mean bond strength of enamel in groups i and ii were 39.47 and 34.65 mpa and in dentin were 45.20 and 36.0 mpa respectively. there was no statistically significant difference between two materials (p=0.190, p=0.082). after six months the bond strength in group i and ii was 35.93 and 35.18 mpa for enamel, and 38.27and 35.19 mpa for dentin respectively, these differences was not statistically significant (p=0.520, p=0.179). after one year, the bond strength of enamel in groups i and ii, were 34.47and 29.91 mpa, and in dentin were 33.86 and 32.53 mpa respectively which was not statistically significant (p=0.609, p=0.991). conclusion : the micro-shear bond strength of both adhesives to enamel and dentin decreased slightly over time; however these decreases were not statistically significant.