Antimicrobial effectiveness of different preparations of calcium hydroxide

Background: Intracanal medicaments have an antibacterial effect on the root canal flora. The effectiveness of such vehicles has to be tested and substantiated against the normal bacterial flora. The various vehicles that were tested for their effectiveness were commercially prepared calcium hydroxide (Metapex), saline, glycerine, CMCP, and Rexidine-M gel. The bacterial cultures tested for sensitivity were aerobes (Staphylococcus aureus, Streptococcus viridans, Streptococcus pyogens, Enterococcus faecalis), anaerobes (Lactobacillus, Bacteroides melaninogenicus) and a commonly found fungus (Candida albicans). One hundred and twenty-five samples were divided into five experimental groups consisting of 21 samples each and one control group of the same size. Aim: The aim of this study was to investigate in vitro the influence of four different vehicles on the effectiveness of calcium hydroxide against the commonly found aerobic and anaerobic bacteria in endodontic infections. Materials and Methods: The samples were taken and transported using standardized techniques and pure growth of each bacterium was isolated. Petri dishes were prepared for the various calcium hydroxide combinations for each bacterium and incubated. The inhibition zone was recorded at three intervals of 24, 96and 168 hours. Results were tabulated and sent for statistical analysis. Results and Conclusions: It was seen that calcium hydroxide and CMCP combination showed the maximum zone of inhibition, and maximum inhibitory effect was seen at 24 hours. The bacteria most susceptible was found to be S. aureus and the least susceptible was E. faecalis. Further clinical studies are required to substantiate these results.