# Effect of ethylenediaminetetraacetic, etidronic, and peracetic acids with different concentrations on the removal of Enterococcus faecalis biofilms from root canal walls: an in vitro study

## TL;DR

This study tests how well different concentrations of acids remove E. faecalis biofilms from root canals, comparing their effectiveness alone and with sodium hypochlorite.

## Contribution

The study introduces new insights into lower concentrations of PAA and HEBP for biofilm removal with reduced harmful effects.

## Key findings

- HEBP with NaOCl reduced E. faecalis viability more than HEBP alone.
- Lower concentrations of PAA and HEBP were as effective as higher ones when used alone or with NaOCl.
- 2% PAA alone was more effective than 9% and 18% HEBP in eliminating biofilms.

## Abstract

E. faecalis is one of the most important microbiological factors responsible for the failures after root canal treatment. The knowledge about the efficacy of HEBP and PAA with different concentrations, when they are used alone or associated with NaOCl on E. faecalis biofilms is limited. In the present study, the efficacy of 17% ethylenediaminetetraacetic acid (EDTA), 9% and 18% etidronic acid (HEBP), and 1% and 2% peracetic acid (PAA), used alone or in combination with sodium hypochlorite (NaOCl), was evaluated on dentine discs experimentally infected with Enterococcus faecalis biofilms using a laser scanning confocal microscope. Irrigation of the samples using HEBP solutions in combination with NaOCl decreased the viability of E.faecalis more effectively compared with the sole use of 9% HEBP and 18% HEBP solutions. The use of two different concentrations of peracetic acid (1–2%) and etidronic acid (9–18%) resulted in similar biofilm elimination when these chelators were used alone or in combination with NaOCl. The sole use of 2% peracetic acid in the experimentally infected samples eliminated more biofilm than the use of 9% and 18% HEBP. Lower concentrations of peracetic acid and etidronic acid can be recommended to remove the E.faecalis biofilms from root canals to decrease the irrigation solutions’ potential harmful effects.