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 NaOCl (1, 3 and 6%) and 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 (i) quantification of bacterial viability, (ii) characterization of three-dimensional architecture and (iii) quantification of extracellular matrix composition using a selective fluorescence-binding assay and confocal microscopy. Data were statistically analyzed by two-way ANOVA and Tukey multiple comparisons test, with significance set at P 0.05). However, against 21-day biofilms, all NaOCl concentrations killed significantly more bacteria than CHX (P < 0.05). All NaOCl concentrations significantly reduced biovolume compared to 2% CHX in young biofilms (P < 0.05), whereas only 3% and 6% NaOCl achieved greater reductions than CHX in mature biofilms (P < 0.05). All NaOCl concentrations significantly outperformed CHX in reducing eDNA and exopolysaccharide levels at both timepoints (P < 0.05). CONCLUSION: CHX exhibited limited antibiofilm activity against mature biofilms, while 3 and 6% NaOCl achieved superior bacterial killing and matrix disruption compared to both 1% NaOCl and CHX in mature biofilms.
Vishwanath et al. (Tue,) studied this question.