Antimicrobial substantivity of chlorhexidine-treated bovine root dentin

Area of Science:

• Endodontics
• Microbiology
• Biomaterials

Background:

• Antimicrobial substantivity of root canal irrigants is crucial for sustained disinfection.
• Previous research indicated chlorhexidine (CHX) provided antimicrobial effects for up to 7 days.
• The long-term efficacy of CHX in dentinal tubules requires further investigation.

Purpose of the Study:

• To evaluate the antimicrobial substantivity of chlorhexidine-treated bovine root dentin over 21 days.
• To compare the efficacy of chlorhexidine against Enterococcus faecalis with saline and sodium hypochlorite (NaOCl).
• To determine the optimal application duration for chlorhexidine's antimicrobial effect.

Main Methods:

• Sixty bovine root sections were irrigated with saline, 2.5% NaOCl, or 0.2% CHX for 5 minutes or 7 days.
• Specimens were incubated in Enterococcus faecalis broth for 21 days with daily re-inoculation.
• Dentin shavings were collected and cultured to assess bacterial colonization in dentinal tubules.

Main Results:

• CHX treatment for 7 days significantly reduced E. faecalis colonization compared to saline and NaOCl groups.
• Shorter CHX application (5 minutes) showed less sustained antimicrobial activity.
• The 7-day CHX group exhibited the lowest bacterial counts in dentinal tubules over the 21-day period.

Conclusions:

• Chlorhexidine demonstrates significant antimicrobial substantivity in root canal dentin when applied for at least 7 days.
• A 7-day application of CHX shows potential as an effective intracanal medicament for prolonged antimicrobial action.
• Further clinical studies are warranted to validate these findings in endodontic treatment.