A comparative in-vitro study of the bactericidal efficacy of sodium hypochlorite and chlorhexidine gluconate plus cetrimide on root canal anaerobic bacterial flora

INTRODUCTION: The permanence of necrotic tissues and/or bacteria may be responsible for persistent root canal infection. Root canal irrigation plays an important role in the success of endodontic treatment given that, on the one hand, it encourages the progressive elimination of the smear layer and, on the other, it neutralises microbic flora within the canal. The aim of this study was to test root canal irrigants from a microbiological point of view: sodium hypochlorite 5% (Niclor Ogna, Milan) and a new generation irrigant based on chlorhexidine gluconate and cetrimide (Cetrexidine VEBAS S. Giuliano Milanese-MI). METHODS: The experiments were performed on a series of obligatory anaerobic bacteria which are most frequently found in the endodontium, all belonging to the international collection "American Type Culture Collection" (ATCC) and supplied by Dasit SpA, Cornaredo (MI). The following bacterial strains were used in the experiment: Actinimyces odontolyticus ATCC 17929, Fusobacterium nucleatum ATCC 25586, Prevotella melanginogenica ATCC 25845, Porphyromonas gingivalis ATCC 33277. The working concentration (CFU/ml) was defined as 0.5 McFarland which corresponds to a concentration of microorganisms equivalent to approx. 1.5 x 10(3) bacteria. Each irrigant was kept in contact with the bacterial species used for this experiment for 10', 20', 30'. RESULTS: The results obtained confirm the bactericidal efficacy of both irrigants used, even after a short contact time. CONCLUSIONS: This does not mean that all irrigants are the same and/or promise the same results. This was a microbiological study, but in practice it is important to bear in mind other variables, such as contact time. Moreover, in order to increase the probability of endodontic treatment, root canal irrigants are also required to satisfy other criteria: biocompatibility, scarce toxicity, high proteolytic power.