Effect of saliva decontamination protocol on the adhesion to dentin with a universal adhesive

Objective: To evaluate the influence and effectiveness of the salivary decontamination protocol after polymerization of a universal adhesive on dentin adhesive strength, after 24 hours and 6 months of ageing. Methods: Fifty intact molars were sectioned in order to obtain two slices of dentin from each tooth. In all specimens except the control group (C - no contamination), after applying and light-curing the adhesive system (Scotchbond Universal), the adhesion surface was contaminated with human saliva, and was then subjected to a decontamination method that differed between groups (W - decontamination with water; W+A - decontamination with water and reapplication of adhesive; E - decontamination with ethanol; E+A - decontamination with ethanol and reapplication of adhesive). Shear bond strength was tested at 24 hours and 6 months of aging, until fracture, and the failure mode was observed. Data were statistically analyzed using non-parametric Mann-Whitney and Kruskal-Wallis tests (α=0.05). Results: At 24 hours of aging, the decontaminant (p=0.289) and the reapplication of the adhesive (p=0.072) did not influence the adhesive strength values, and all contaminated groups obtained significantly (p<0.05) lower adhesive strength values than the control group. At 6 months, the reapplication of the adhesive (W+A and E+A) provided increased adhesion values (p=0.001), but no differences were observed between the decontaminants (p=0.314). Only the W+A group yielded a statistically (p=0.376) similar value to the control group. Conclusion: When there is salivary contamination of the adhesion area after polymerization of the universal adhesive tested, water decontamination should be performed followed by a reapplication of the adhesive.