In vitro antibacterial activity of different endodontic irrigants.

AIM: The objective of this study was to compare in vitro the antibacterial activity of Tetraclean (mixture of doxycycline, citric acid and polypropylene glycol), Niclor 5 (5.25% sodium hypochlorite solution), Cloreximid (0.2% chlorhexidine and 0.2% cetrimide solution) and hydrogen peroxide 12 volumes on three endodontic pathogens associated with primary endodontic infections. Enterococcus faecalis, Streptococcus mutans and Staphylococcus aureus strains were selected to evaluate the antibacterial activity of endodontic irrigants by the agar disc-diffusion test. MATERIAL AND METHODS: Paper discs were saturated with each one of the test solutions (at room temperature and preheating at 50°C) and placed onto culture agar-plates preadsorbed with bacterial cells and further incubated for 24 h at 37°C. The growth inhibition zones around each irrigant were recorded and compared for each bacterial strain. Kruskal-Wallis and Mann-Whitney tests were applied to compare the various groups. RESULTS: At room temperature, Tetraclean showed significantly higher inhibition of bacteria growth than all other irrigants tested. Preheating at 50°C significantly increased growth inhibition for all the groups tested. At 50°C, hydrogen peroxide 12 volumes and Tetraclean showed significantly higher efficacy than all other irrigants tested. CONCLUSIONS: 50°C-preheated hydrogen peroxide 12 volumes and Tetraclean showed highest inhibition of the bacterial growth.

Antimicrobial activity of sodium hypochlorite-based irrigating solutions.

PURPOSE: The objective of the present study was the in vitro evaluation of the antimicrobial activity of three different NaOCl-based endodontic irrigating solutions: a 5.25% conventional sodium hypochlorite solution; and two new irrigating solutions, a 5.25% sodium hypochlorite solution with the addition of a proteolytic enzyme and a surfactant; and a 5.25% sodium hypochlorite gel with inorganic silicate. METHODS: Enterococcus faecalis, Staphylococcus aureus and Streptococcus mutans strains were selected to evaluate the antimicrobial activity of the endodontic irrigating solutions by the agar disc diffusion test. Paper disks were saturated with each one of the tested solutions (at room temperature and pre-warmed at 45°C) and placed onto culture agar-plates pre-adsorbed with bacterial cells and further incubated for 24 h at 37°C. The growth inhibition zones around each irrigating solution were recorded and compared for each bacterial strain. RESULTS: The results were significantly different among the tested irrigating solutions: 5.25% sodium hypochlorite solution produced the highest inhibition areas; 5.25% sodium hypochlorite solution with a proteolytic enzyme and a surfactant, and 5.25% sodium hypochlorite gel with inorganic silicate showed the lowest zones of inhibition. CONCLUSIONS: Even if all tested irrigating solution possessed antibacterial activity versus all tested bacterial strains, 5.25% sodium hypochlorite solution with a proteolytic enzyme and a surfactant, and 5.25% sodium hypochlorite gel with inorganic silicate showed lower in vitro efficacy than 5.25% conventional sodium hypochlorite solution.