An in vitro and ex vivo study on two antibiotic-based endodontic irrigants: a challenge to sodium hypochlorite.

Amongst the bacterial species which most often cause endodontic failures, Enterococcus faecalis is the most important. This study compared the effectiveness of sodium hypochlorite and two new generation antibiotic-based endodontic irrigants, Tetraclean and MTAD. By means of an in vitro agar dilution assay, we show that both Tetraclean and MTAD are 100% effective against 54 clinical isolates at dilutions up to 1:256 and 1:1048, respectively, whereas sodium hypochlorite completely loses its effectiveness when diluted more than 32 times. The bactericidal effect of both Tetraclean and MTAD can be ascribed not just to their antibiotic component per se, but also to a synergistic effect among the several ingredients included in the formulations. Moreover, by an ex vivo model of teeth extracted and experimentally infected with E. faecalis ATCC 29212, we show that both the antibiotic-based endodontic irrigants are effective in eliminating bacterial cells in 93 to 100% of the test samples. The results of these pre-clinical studies strongly support a wider use of this new group of endodontic irrigants in daily clinical practice.

Comparative in vitro and ex vivo studies on the bactericidal activity of Tetraclean, a new generation endodontic irrigant, and sodium hypochlorite.

The aim of this study was to compare the efficacy of a new generation endodontic irrigant, Tetraclean, to the widely used sodium hypochlorite. Tetraclean combines a powerful detergent effect with a strong antimicrobial efficacy, whereas sodium hypochlorite has several drawbacks and is sometimes ineffective in preventing microbial-mediated endodontic failure. The bactericidal activity of both irrigants against Enterococcus faecalis, the most commonly isolated species from root canals of teeth with post-treatment disease, was assessed i) in vitro, according to the European Standard lines for the evaluation of the bactericidal activity of chemical disinfectants, and ii) with an ex vivo model of extracted and decoronated human teeth, infected with E. faecalis and subsequently irrigated with either of the irrigants. Both irrigants display very similar bactericidal activity against E. faecalis in vitro. However, the ex vivo model shows that only in the teeth irrigated with Tetraclean did the bacterial burden gradually drop until no bacteria were detectable a few days post-irrigation. Vice versa, in the teeth irrigated with sodium hypochlorite, the drop in the bacterial burden was rapid but temporary and most of the teeth were colonized again by 48 hours post-irrigation.