# A Comparison of Disinfecting Ability of Peracetic Acid, Glutaraldehyde and Autoclaving on Endodontic K-files Tested Against Enterococcus faecalis: An In-Vitro Study

## TL;DR

This study compared three disinfection methods for endodontic files contaminated with a resilient bacteria and found all equally effective in a lab setting.

## Contribution

Demonstrated equal disinfecting efficacy of PAA, glutaraldehyde, and autoclaving against E. faecalis on K-files in vitro.

## Key findings

- All three methods achieved complete microbial eradication with no bacterial presence detected.
- No statistical differences were observed between the disinfection methods in this in-vitro study.
- Further in vivo studies are needed to validate these findings and assess instrument longevity.

## Abstract

Aim

This in-vitro study aimed to compare the disinfecting efficacy of peracetic acid (PAA), glutaraldehyde, and autoclaving on endodontic K-files contaminated with Enterococcus faecalis (E. faecalis), a resilient pathogen frequently present in persistent root canal infections.

Materials and methods

Twenty-four pre-sterilized nickel-titanium (NiTi) K-files (Mani, Inc., Japan) #10 (25 mm) were infected with a standard strain of E. faecalis and randomly divided into three groups (n=8). Group I was treated with 50% PAA (Microgen Hygiene Pvt. Ltd, India) Group II with 2% Glutaraldehyde (3M, India)for 4 hours, and Group III was subjected to autoclaving (Runyes Medical Instrument Co., Ltd., Ningbo, China) at 121°C at 15 lbs of pressure for 15 minutes. Disinfection efficacy was assessed via turbidity testing in peptone water, blood agar plate streaking, and Gram-stain microscopy to detect bacterial presence.

Results

All three disinfecting methods achieved complete microbial eradication. There was no turbidity observed in peptone water, no bacterial colonies on blood agar plates, and no Gram-positive cocci were observed under microscopic examination in any group. As all treatment modalities demonstrated full efficacy, statistical comparison was deemed unnecessary.

Conclusion

PAA, glutaraldehyde, and autoclaving demonstrated equal efficacy in disinfecting E. faecalis-contaminated K-files under in-vitro conditions. Given their comparable performance, the choice of sterilization method may be guided by clinical feasibility, cost, and impact on instrument longevity. Further in vivo studies are needed to validate these findings and assess the long-term effects on instrument integrity.