Effect of the association of different substances at the physical and antimicrobial properties of the EDTA
Palavras-chave:benzalkonium chloride; EDTA; Enterococcus faecalis.
We aimed to assess the physical, chelating, antibacterial properties and cytotoxicity of EDTA used with and without antibacterial additives. Material and methods: Solutions of 17% EDTA with or without additives together with 2.5% sodium hypochlorite and saline control were tested. The antibacterial properties of the solutions were assessed using a biofilm which was inoculated in human dentine either before exposure to irrigating solution or after. The smear layer removal capacity was tested by using scanning electron microscopy (SEM). The irrigants were also evaluated for dentine wettability by the sessile drop method, and the surface tension of solutions was verified by the pendent drop test. The effect of irrigating solutions on fibroblast cell viability was assessed by reducing MTT assay. Results: The addition of antibacterial substances to EDTA resulted in improving its antibacterial action against Enterococcus faecalis biofilm, without compromising the EDTA chelating action or elevating its cytotoxicity. Lower surface tension and better wettability of the irrigants was obtained by sodium hypochlorite or by adding benzalkonium chloride or N-acetylcysteine to EDTA. Conclusion: EDTA-benzalkonium chloride showed effectiveness not only preventing the formation of biofilm and root canal re-infection, but also against Enterococcus faecalis biofilm itself. It also lowered EDTA surface tension and allowed better dentine wettability, being outstanding compared with the other chelator solutions. Therefore, the use of this association as a final rinse in endodontic treatment should be further studied.