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Updated: May 2, 2026
Concurrent Quantification of Cellular and Extracellular Components of Biofilms
Published on: December 10, 2013
Effect of Root Canal Irrigants on the Microbial Viability and Matrix Composition of Young and Mature Polymicrobial
Vijetha Vishwanath1, Akhila Pudipeddi2, Prasanna Neelakantan3
1Faculty of Medicine and Dentistry, Mike Petryk School of Dentistry, University of Alberta, Edmonton, Canada; Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, PR China.
Introduction:
Disinfection is critical for regenerative endodontic procedures, yet the antibiofilm activity of root canal irrigants remains poorly characterized. This study investigated the effects of sodium hypochlorite (NaOCl) (1, 3, and 6%) and chlorhexidine (CHX) (2%) on biofilm viability and extracellular matrix composition.
Methods:
Multispecies biofilms were developed for 7 or 21 days and treated with CHX or NaOCl. Untreated biofilms served as controls. Biofilms were subject to multimodal assessment including (1) quantification of bacterial viability, (2) characterization of three-dimensional architecture, and (3) quantification of extracellular matrix composition using a selective fluorescence-binding assay and confocal microscopy. Data were statistically analyzed by 2-way analysis of variance (ANOVA) and Tukey multiple comparisons test, with significance set at P < .05.
Results:
Both NaOCl and CHX significantly reduced biofilm bacterial viability compared to the untreated control in 7-day old biofilms (P < .05), with no significant difference between any NaOCl concentration and CHX (P > .05). However, against 21-day biofilms, all NaOCl concentrations killed significantly more bacteria than CHX (P < .05). All NaOCl concentrations significantly reduced biovolume compared to 2% CHX in young biofilms (P < .05), whereas only 3% and 6% NaOCl achieved greater reductions than CHX in mature biofilms (P < .05). All NaOCl concentrations significantly outperformed CHX in reducing eDNA and exopolysaccharide levels at both timepoints (P < .05).
Conclusion:
CHX exhibited limited antibiofilm activity against mature biofilms, while 3 and 6% NaOCl achieved superior bacterial killing and matrix disruption compared to 1% NaOCl and CHX both in mature biofilms.
