Purpose: To evaluate the influence of a 2% chlorhexidine solution (CHX) on the bond strength and nanoleakage of two self-etching adhesive systems on demineralized dentin over a 12-month period. Materials and Methods: The middle dentin from sound third molars was exposed and demineralized in vitro. Twelve groups were formed using different adhesive systems (Clearfil Protect Bond [PB], Clearfil SE Bond [SE]) dentin treatment (with or without CHX application), and water-storage times (24 h, 6 and 12 months). Composite resin cylinders were bonded to the prepared dentin, and these specimens underwent microshear bond strength (mu SBS) testing and nanoleakage evaluation. mu SBS data were submitted to a three-way ANOVA and Tukey's test. The failure mode and nanoleakage were analyzed descriptively by score. Results: There was a statistically significant interaction only between the adhesive system and CHX, and adhesive system and water-storage times. SE showed the lowest mu SBS just at 24 h water-storage time regardless of CHX. A significant decrease in mu SBS values after 6 months of water storage occurred in all of the groups and was maintained until 12 months. Adhesive failure increased with storage time. All groups showed nanoleakage at the resin/dentin interfaces and an increased silver deposition was noticed after 6 and 12 months of water storage. The highest percentages of nanoleakage were found in CHX groups. Conclusion: CHX did not interfere with mu SBS values for either self-etching adhesive system, but water storage did. Bond strength decreased for both adhesive systems after 6 and 12 months, regardless of CHX application. Nano leakage increased with water-storage time and with CHX application.14657558
