In Vitro And Animal Study On Antimicrobial Activity Of Calcium Hydroxide

Root canal therapy is a method of treating pulp necrosis and periapical diseases with the help of periapical tissues which are characterized by abundant blood flow and strong ability of repair and regeneration. The stimulation from root can be eliminated through following steps: preparation, disinfection and obturation of the root canal. Main purpose of the treatment is to cure the teeth with pulp necrosis or periapical diseases. The function of root canal disinfection is to control or kill the remaining bacteria in the root canal, relieve pain, control exudation and induce apical part of a root to complete development.Many studies at home and abroad have focused on the antimicrobial activity of calcium hydroxide in recent years. However, most of the studies evaluate the antimicrobial activity of calcium hydroxide on the culture plate. Thus, the purpose of this study is to evaluate the antimicrobial activity of calcium hydroxide on the extracted human teeth and the canine teeth. The experiment was divided into twoparts:1. In vitro study on antimicrobial activity of four intracanal medicineTo compare the antimicrobial activity of Ca(OH)₂ Iodoform, FC and Vitapex against the bacteria in the root canal of human extracted teeth in vitro. Freshly extracted fifty single-rooted human teeth were selected for this experiment and cut at the amelocemental junction. All roots were randomly divided into five groups of 10 roots each. After simply removing pulp tissues, the bacteria were incubated into each canal. The bacteria in each canal were sampled and counted under light microscope before and after preparing the root canals and then four kinds of intercanal medicine were sealed in. The bacteria sampled and counted again after 7 days .The results showed that the bacteria in root canals of each group reduced significantly after root canal preparation (P<0.05) . However the antimicrobial activity of four intercanal medicine was not significant (P>0.05) .2. The research of antimicrobial activity of four intracanal medicine on bacteria from canine root canalThe single-canal teeth of four health adult canine were selected for the experiment. The animal model of periapical disease was established after removing the pulp of the teeth and feeding for three months. The bacteria in each canal were sampled and counted under light microscope before and after preparing the root canals and then four kinds of intercanal medicine sealed. The bacteria sampled and counted again after 7 days.The results showed that the bacteria in root canals of each group reduced significantly after root canal preparation (P<0.05) . However...