All endodontic instruments create dentinal debris and a smear layer as a corollary of their action on root canal walls. Canal enlargement aims at allowing ample space to act as a reservoir for irrigation, removing the superficial layer of infected dentine and producing a shape that facilitates canal obturation. Thorough instrumentation of the apical region has long been considered to be an essential component in the cleaning and shaping process.The apical portion of the root canal system can retain microorganisms that could potentially cause periradicular inflammation, therefore treatment interventions that exploit removal of pathogens should be indicated in the treatment of infected root canal systems. Endodontic instruments have been undergoing modifications over time, in both their design and composition. A vital advancement in endodontics was the introduction of instruments made from the NiTi alloy. This book highlights the efficacy of newer rotary instruments: Protaper,Mtwo and Hero shaper in the apical third of root canal.