2012 год. LAP Lambert Academic Publishing Biomechanical preparation, disinfection and obturation all together constitute equally important phases of endodontic treatment. Chemomechanical preparation of the root canal through a combination of mechanical instrumentation and antibacterial irrigation is the critical stage in canal disinfection. During the last decade, several new nickel titanium instruments for manual root canal preparation as well as for use in a rotary endodontic handpiece have been developed in order to facilitate the difficult and time consuming process of cleaning and shaping the root canal system and to improve the final quality of root canal preparation. The comparative evaluation of the new instruments to remove smear layer material produced during endodontic preparation is unknown. Aim of this study is to assess smear layer formation following canal preparation using Endowave, K3 and ProTaper using Scanning Electron Microscope.