Evaluation of antimicrobial effects of different calcium hydroxide preparation methods with direct exposure test

Calcium hydroxide has a pronounced antimicrobial activity against most of the bacterial species found in the root canal and now is widely used as an intracanal medicament in endodontic therapy. The aim of this study was to evaluate the antimicrobial effect of different calcium hydroxide preparations with Normal saline, Lidocaine 2%, Chlorhexedin 2% and 0/2%, Iodine Potassium Iodide 2% and Glycerin on Entrococcus faecalis with direct exposure method. For conducting this experimental in-vitro study 375 sterile paper points were contaminated with the microbial suspension of Entrococcus faecalis. The samples were placed in sterile dishes and covered with creamy mixture of six different calcium hydroxide preparations. After 1, 3, and 7 days the paper points were immersed in test tubes containing BHI. Microbial growth was evaluated by turbidity in culture mediums. Data obtained showed that all of tested materials had perfect antimicrobial action but only in calcium hydroxide with Chlorhexidine 2% and 0.2% groups perfect antimicrobial action and no microbial growth was observed after 24 hours. Regarding the results of this study it is concluded that the vehicle of calcium hydroxide has not any significant effect on its antimicrobial activity, however, more studies on the effect of vehicles of chemical properties of calcium hydroxide such as its diffusion in similar conditions of root canal system, are needed.