Antimicrobial and biocompatible potential of a peracetic acid-based disinfectant as a novel root canal irrigant

Sodium hypochlorite (NaClO) is widely used as a root canal irrigant because it is an effective antimicrobial agent; however, cytotoxicity to periapical tissues remains a clinical concern. Peracetic acid (PAA) is a well-established disinfectant, but its oral biocompatibility, particularly at low concentrations, and commercially formulated preparations have not been fully evaluated.

The antimicrobial efficacy and biocompatibility of a low-concentration PAA-based commercial disinfectant (Actril) were tested against representative oral pathogenic bacteria. Minimum inhibitory, bactericidal, and biofilm inhibitory concentrations were determined, and cytotoxicity toward gingival epithelial cells and periodontal ligament fibroblasts was assessed. Bactericidal activity against Enterococcus faecalis biofilms were evaluated using live/dead staining. Irrigation efficacy was further examined in E. faecalis-infected extracted human teeth using scanning electron microscopy and quantitative polymerase chain reaction.

Actril exhibited antimicrobial activity at PAA-equivalent concentrations markedly lower than those required for NaClO, with reduced cytotoxicity toward periodontal tissue-related cells. Live/dead staining demonstrated bactericidal effects within E. faecalis biofilms, although variability was observed at threshold concentrations. In extracted tooth models, Actril facilitated biofilm disruption and exposure of dentinal tubules within a clinically relevant irrigation time. Quantitative analyses confirmed significant reduction of bacteria compared with non-irrigated controls, comparable to the effects of NaClO.

Although PAA itself is not a novel antimicrobial agent, a low-concentration, commercially formulated PAA-based disinfectant demonstrated a favorable balance between antimicrobial efficacy and biocompatibility in oral biofilm models. These findings support the potential application of PAA as a low-toxicity antimicrobial strategy in endodontic environments.