Antibacterial Activity of Epoxy Incorporated Amine Nanoparticles on Enterococcus Faecalis Biofilm

Objectives: Root canal (endodontic) treatment failure can result from reinfection of the root canal by residual bacterial biofilm. The aim of the present study was to test the in vitro antibacterial effect of epoxy incorporated amine nanoparticles against existing biofilm of the test bacteria Enterococcus faecalis.
Methods: Enterococcus Faecalis (51299 ATCC) biofilms were grown in a 96 well microplate for 48 hours at 37^oC under aerobic conditions. Following incubation, the growth medium in each well was discarded and replaced by 100 mL saline. Six mm diameter epoxy discs (3mm thickness), incorporated with various concentrations of immobilized amine particles (0.4, 0.8, 1.6, 3.3% w/v) or without any addition (as control), were placed on top of the grown biofilm in direct contact for one hour at 37^oC under aerobic conditions. Following the second incubation, the tested discs were removed and biofilms were disrupted and stained using Bacteria Live/Dead assay (PromoKine). The Live/Dead bacterial ratio was determined using fluorescence microscopy by analyzing digital images of six random fields of the slides prepared from each biofilm.
Results: Whereas some reduction occurred in biofilm vitality at the lower amine particles concentrations (i.e. 0.4 and 0.8% w/v) as compared to the no-addition control, these were not statistically significant (p=0.456 and p=0.371, respectively). However, significant reductions in biofilm viability were observed in the higher concentrations of 1.6 and 3.3% w/v (p<0.001 for both).
Conclusions: The results suggest that epoxy incorporated with 1.6% w/v and above of amine nanoparticles, may be effective against residual bacterial biofilm in treated root canals.