Final Endodontic Irrigation with 2% Peracetic Acid: Antimicrobial Activity and Cytotoxicity

Area of Science:

• Biomaterials Science
• Microbiology
• Cell Biology

Background:

• Dental infections often involve biofilms, necessitating effective antimicrobial agents.
• Sodium hypochlorite (NaOCl) and chlorhexidine (CHX) are common endodontic irrigants with known efficacy and cytotoxicity.
• Peracetic acid (PAA) is an alternative disinfectant with potential antimicrobial and cytotoxic properties.

Purpose of the Study:

• To compare the cytotoxicity and antimicrobial efficacy of 2% peracetic acid (PAA) against 5.25% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX).

Main Methods:

• Cytotoxicity was assessed using the MTT assay on ECV 304 endothelial cells exposed to serial dilutions of NaOCl, CHX, and PAA.
• Antimicrobial efficacy was evaluated against Enterococcus faecalis biofilms grown on dentin blocks.
• Colony forming units (CFU) were counted after treatment with NaOCl, CHX, or PAA.

Main Results:

• PAA exhibited significantly higher cell viability compared to NaOCl and CHX.
• NaOCl and CHX demonstrated statistically significant antimicrobial effects against the bacterial suspension (p < 0.001).
• PAA showed a reduction in CFU growth but lacked superior in vitro antimicrobial activity against mature Enterococcus faecalis biofilms.

Conclusions:

• PAA presents a favorable cytotoxicity profile compared to NaOCl and CHX.
• Despite its lower cytotoxicity, PAA did not prove more effective than NaOCl or CHX against established Enterococcus faecalis biofilms in vitro.