Effect of electric currents on antibacterial effect of chlorhexidine against Entrococcus faecalis biofilm : An in vitro study

This in vitro study was mainly aimed to evaluate the effect of high-frequency alternating currents (AC) applied by an electronic apex locator (EAL) on the antibacterial properties of chlorhexidine (CHX) on E. faecalis biofilm. The root canals of 120 extracted human single-rooted teeth were prepared using Gates-Glidden drills and hand K-files. After contaminating the root canals with E. faecalis, they were incubated for 60 days. Then, the teeth were randomly divided into six experimental groups (n=20). Group 1, 2% CHX; group 2, normal saline (NS) with direct current (DC); group 3, normal saline (NS) with high-frequency alternating current (AC); group 4, 2% CHX with DC; group 5, 2% CHX with AC; group 6, control (normal saline). The samples were collected from the root canal walls of 16 teeth in each group and 1:10 serial dilutions were prepared and added to Muller-Hinton agar (MHA) plates and incubated at 37°C for 48 h. The longitudinal sections of the other 4 teeth used to observe under a scanning electron microscope (SEM). A classic colony counting technique was used for counting the vital E. faecalis bacteria in MHA. Two-way ANOVA was used for statistical analysis of the data. The level of significance was set at P<0.05. The electric current significantly changed the colony-forming units (CFU) values (P<0.001). According to pair-wise comparisons, the highest CFU difference was observed between the AC group and the group without electric current (P<0.001); furthermore, the difference between the DC group and the group without electric current was not significant (P=0.823). The highest bioelectric effect occurred with the use of high-frequency alternating electric current in the form of an apex locator with CHX as a canal irrigant

Antimicrobial efficacy of different concentration of sodium hypochlorite on the biofilm of Enterococcus faecalis at different stages of development

Persistent infection of the root canal due to the presence of resistance bacterial species, such as Enterococcus faecalis, has always been one of the most important reasons for endodontic treatment failure. This study investigated the antimicrobial efficacy of 1%, 2.5 % and 5% sodium hypochlorite in eliminating E. faecalis biofilms at different stages of development. In this study 4-, 6- and 10-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS) or 1%, 2.5% and 5% NaOCl. Dentin chip suspensions were used for colony forming unit (CFU) counting to estimate remaining E. faecalis counts. Statistical comparison of the means was carried out with Kruskal-Wallis test, and pair-wise comparisons were made by Mann-Whitney U test, at a significance level of P<0.05. The results showed that 2.5% and 5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 85.73%, 81.88% and 78.62% decreases in bacterial counts in 4-, 6- and 10-week-old biofilms, respectively, which was significantly more than those with PBS (p<0.05). The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival rate and residual bacteria increased with biofilm aging

Comparative antibacterial effects of ginger and marjoram extract versus conventional irrigants on mature Enterococcus faecalis biofilms : an in vitro study

This study evaluated antibacterial effects of Ginger and Marjoram extract compared with Routine Intracanal Irrigants on Mature Enterococcus faecalis Biofilms. Sixty-six extracted human teeth, were randomly assigned to four groups 5.25% sodium hypochlori

J Clin Exp Dent-AHEAD OF PRINT Antimicrobial efficacy of different concentration of sodium hypochlorite on the biofilm of Enterococcus faecalis at different stages of development

Abstract Background: Persistent infection of the root canal due to the presence of resistance bacterial species, such as Enterococcus faecalis, has always been one of the most important reasons for endodontic treatment failure. This study investigated the antimicrobial efficacy of 1%,2.5 % and 5% sodium hypochlorite in eliminating E. faecalis biofilms at different stages of development. Material and Methods: In this study 4-, 6-and 10-week-old E. faecalis biofilms were subjected to one of the following approaches: phosphate-buffered saline solution (PBS) or 1%, 2.5% and 5% NaOCl. Dentin chip suspensions were used for colony forming unit (CFU) counting to estimate remaining E. faecalis counts. Statistical comparison of the means was carried out with Kruskal-Wallis test, and pair-wise comparisons were made by MannWhitney U test, at a significance level of P&lt;0.05. Results: The results showed that 2.5% and 5% NaOCl completely eliminated E. faecalis biofilms in three stages of biofilm development, whereas 1% NaOCl resulted in 85.73%, 81.88% and 78.62% decreases in bacterial counts in 4-, 6-and 10-week-old biofilms, respectively, which was significantly more than those with PBS (p&lt;0.05). Conclusions: The bacteria in mature and old biofilms were more resistant to 1% NaOCl than were the bacteria in young biofilms. Overall survival rate and residual bacteria increased with biofilm aging