IN-VITRO ANTIBACTERIAL EFFICIENCY OF IRRIGATION REGIMENS AGAINST BIOFILM OF ENTEROCOCCUS FAECALIS

Objectives: the aim of this study was to compare the antibacterial efficiency of 2.25% sodium hypochlorite (naocl), 2% chlorhexidine (chx), and gaseous ozone to biofilm of enterococcus faecalis (e. faecalis) generated on cellulose nitrate membrane filters. materials and methods: after an overnight culture of e. faecalis grown in tryptic soy (tyc) broth, an aliquot of 100μl of microorganisms was seeded onto 13.0-mm diameter cellulose nitrate membrane filters (sartorius®, uk) and incubated for 48 to 72 h at 37ºc in an aerobic atmosphere. twenty membranes were used for each test agent. then, biofilm formation test agents, gaseous ozone, and 0.9% nacl (positive control) were applied at time intervals. application periods for naocl and chx were 5 to 10 minutes, whereas ozone application with ozonytronx (bizonix, gmbh, germany) was 80 to 120 seconds. next, from each of the samples, 100μl aliquots were put onto the tyc agar plates. incubation colonies were calculated as colony forming units (cfu/ml) per membrane and observed by scanning electron microscopy (sem). data were analyzed using the wilcoxon test, kruskal-wallis test, and mann-whitney u-test at p<0.05. results: all of the irrigation regimens disgregated and removed the biofilm compared to the positive control (p<0.05).however, both 2.25% naocl and 2% chx caused a significantly higher degree of biofilm disgregation than ozone application (p<0.05). conclusions: the irrigation regimen of 2.25% naocl and 2% chx was more effective in eliminating biofilm formation of e. faecalis. however, the long-term irrigation regimen of ozone was found to be a successful alternative for endodontic treatment.