This book is relevant as it states the first randomized controlled trial to compare the effect of two medicaments (Calcipex and Metapex). It has higher relevance as compared to the in-vitro studies, which does not show the full clinical potential of an intracanal medicament and omits the effects of clinician's skills, intra oral factors and other related limitations. The evaluation was done using bacterial culture CFU/ml which is considered as the gold standard method. Conditions were standardized and appropriate disinfection protocol was followed.