Bactericidal Effect of Strong Acid Electrolyzed Water against Flow Enterococcus faecalis Biofilms

• Both flow and static Enterococcus faecalis biofilms were developed.
• The bactericidal effect of strong acid electrolyzed water (SAEW) on E. faecalis biofilms was tested.
• SAEW showed a bactericidal effect similar to that of 5.25% NaOCl on E. faecalis biofilms.
• SAEW showed the potential to be a root canal irrigant for root canal disinfection.

IntroductionThis study evaluated the bactericidal effect of strong acid electrolyzed water (SAEW) against flow Enterococcus faecalis biofilm and its potential application as a root canal irrigant.MethodsFlow E. faecalis biofilms were generated under a constant shear flow in a microfluidic system. For comparison, static E. faecalis biofilms were generated under a static condition on coverslip surfaces. Both the flow and static E. faecalis biofilms were treated with SAEW. Sodium hypochlorite (NaOCl, 5.25%) and normal saline (0.9%) were included as the controls. Bacterial reductions were evaluated using confocal laser scanning microscopy and the cell count method. Morphological changes of bacterial cells were observed using scanning electron microscopy.ResultsThe confocal laser scanning microscopic and cell count results showed that SAEW had a bactericidal effect similar to that of 5.25% NaOCl against both the flow and static E. faecalis biofilms. The scanning electron microscopic results showed that smooth, consecutive, and bright bacteria surfaces became rough, shrunken, and even lysed after treated with SAEW, similar to those in the NaOCl group.ConclusionsSAEW had an effective bactericidal effect against both the flow and static E. faecalis biofilms, and it might be qualified as a root canal irrigant for effective root canal disinfection.