effect of salivary contamination during different bonding stages on shear dentin bond strength of one-step self-etch and total etch adhesive

objective: this study evaluated the effect of saliva contamination during bonding procedures without removing saliva on shear dentin bond strength of three adhesive generations when rubber dam isolation is not feasible. materials and methods: flat superficial dentin surfaces of seventy-two extracted human molars were randomly divided into three groups (a: scotch bond mp plus (sbmp), b: single bond (sb), c: prompt l-pop) according to the applied adhesives and twelve subgroups (n=6) according to the following saliva contamination applied in different bonding steps. the specimens were contaminated with saliva after etching (a1 and b1), after primer application (a2), after adhesive application before polymerization (a3, b2 and c1), and after adhesive polymerization (a4, b3 and c2). three subgroups were not contaminated as controls (a5, b4 and c3). resin composite was placed on dentin subsequently followed by thermocycling. shear test was performed by universal testing machine at 0.5 mm/min crosshead speed. the collected data were statically analyzed using one and two-way anova and tukey hsd. results: in contrast to sbmp and sb, the mean shear bond strength of promote l-pop was not significantly different between contaminated and uncontaminated subgroups. mean shear bond strengths of sbmp subgroups contaminated after adhesive polymerization or uncontaminated were significantly higher compared to the other two groups (p<0.05). conclusion: unlike promote l-pop, saliva contamination could reduce shear bond strength of the total-etch adhesives. furthermore, the step of bonding procedures and the type of adhesive seems to be effective on the bond strength of adhesive contaminated with saliva.