Method: Chlorhexidine diacetate (99.9%, Sigma) was added to an adhesives system (Ambar, FGM) in the following concentrations: 0.0% (control); 0.01%; 0.05%; 0.1%; and 0.2%. The adhesive was applied according to manufacturer's instructions on a flat occlusal demineralized dentin of 25 human molars (n = 5 for experimental condition). Composite build-ups were constructed incrementally and specimens (0.8 mm2) were prepared.. Half of sticks were immediately tested and another half were stored in distilled water (37oC) for 6-month. For NL, 2 bonded sticks from each tooth in each time were coated with nail varnish, placed in the silver nitrate, polished down with SiC papers and analyzed by EDX-SEM. The rest of the sticks were tested on microtensile BS testing at 0.5 mm/min in both time. The data were submitted to a two-way ANOVA and Tukey's test (α = 0.05).
Result:
No significant degradation was found for BS values when different concentrations of chlorhexidine were added to adhesive system, as well as, the control group (p > 0.05). Regarding to NL, in all groups a significant increasing of silver nitrate was observed (p < 0.05), however, the highest value was found in the control group (p < 0.05).
Conclusion: The addition of chlorhexidine in simplified adhesive system preserves the degradation of Resin-dentin Bonds in all concentration tested.