Abstract
The aim of this study was to evaluate the in vivo efficiency of endodontic treatment with calcium hydroxide in chronic apical periodontitis by determining the microbial load from the endodontic space in different stages of treatment. The microbiological determinations that have been made have led to the conclusion that calcium hydroxide possesses a redoubltable antimicrobial activity, but only with the condition of long-lasting contact with the root canals. Another important result is the essential role of the rigorous biomechanical treatment of the root canals, intracanal medication with calcium hydroxide is addresses mostly to microorganisms located in root canal ramifications.