Comparative evaluation of antibiofilm efficacy of chitosan nanoparticle- and zinc oxide nanoparticle-incorporated calcium hydroxide-based sealer: An In vitro study

Aim: This study evaluated the antibiofilm efficacy of calcium hydroxide-based sealer incorporated with chitosan nanoparticles (CS-NPs) and zinc oxide nanoparticles (ZnO-NPs) against two strains of Enterococcus faecalis (ATCC 29212, OG1RF). Materials and Methods: The materials tested were Apexit Plus sealer in the commercial unmodified form and two modified forms with CS-NP and ZNO-NP, respectively. Crystal violet assay and confocal laser scanning microscopy (CLSM) study were used to assess the bacterial viability of biofilms grown in wells of microtiter plate and glass slides, respectively. Two E. faecalis strains (ATCC 29212, OG1RF) were used for the study. Results: The crystal violet assay done on E. faecalis strain ATCC 29212 showed a significant decrease in the optical density (OD) value with ZNO-NP-incorporated calcium hydroxide sealer when compared with CS-NP. In the case of E. faecalis strain OG1RF, only ZNO-NP-incorporated calcium hydroxide-based sealer showed reduction in the OD value. In CLSM study done on E. faecalis strain ATCC 29212, only ZNO-NP-incorporated calcium hydroxide-based sealer showed reduction in the thickness of biofilm. No groups of OG1RF strain showed reduction in the thickness of biofilm. Conclusion: The incorporation of nanoparticles (ZnO and CS) into calcium hydroxide-based sealers significantly enhances the antibiofilm efficiency against E. faecalis strain ATCC 29212 but has questionable effectiveness against E. faecalis strain OG1RF. The present study demonstrates that ZNO-NP shows better antibiofilm efficacy than CS-NP against both strains of E. faecalis.