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 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. The samples were taken and transported using standardized techniques and pure growth of each bacterium was isolated. The inhibition zone was recorded at three intervals of 24, 96 and 168 hours....