Introduction Root canal therapy has been a primary modality to treat the teeth with infected root canals. The treatment is carried out with the primary aim to remove the infected tissue and at the same time maintain the root canal anatomy 1. Endodontic treatment used to be a tedious procedure in the past requiring multiple visits for completion of procedure 2. The latest developments in the equipment used for endodontics such as magnifying devices, electronic apex locators, engine driven rotary nickel titanium files etc. have not only enhanced the success rates of these procedures but have also substantially decreased the time and visits needed for treatment completion. These contemporary devices can help the clinician complete the endodontic treatment in a single visit. Practice of nickel titanium (NiTi) rotary file is becoming ubiquitous because it has shape memory and better flexibility compared to stainless steel files. Niti instruments are anticipated to perform better by remaining centred in the canal during root canal instrumentation because of their increased flexibility. These are employed for mechanical preparation of root canals during endodontic treatment or removal of gutta percha points if needed. It has been in use since 1991, and endo motors are used to prepare the canals. These properties make them better than conventional stainless-steel files. These files maintain the canal morphology thus minimizing the procedural errors like canal transportation, apical debris extrusion, perforation and change in canal centrality etc. 2,24,25 . A comprehensive knowledge regarding the root canal morphology is important to perform adequate treatment. The dental pulp is the living and soft tissue part of the tooth enclosed in its root canals and pulp chamber. It resides in the internal spaces of the tooth. The outer border of pulp cavity imitates the shape of the tooth. Recent literature reveals that root canal system is not a solitary canal extending unvaryingly from the orifice to the apex, rather it is intricate because of division and fusion of canals as they progress to the root apex. The root canal begins from the orifice located in the pulp chamber and runs through the roots to open into the periodontium via the apical foramen 3. These varied configurations can be classified so that their shape is easy to identify, communicate and for adequate treatment planning based on the shape of the canal. An ideal classification system for the root canals should define the number of roots, the canals present within these roots and their configuration running from the orifice to the apex 4. As the endodontic treatment showed advances and new sources of technical applications in clinical practice, it became easier to identify the diagnosis and quality of treatment given. One of these very important advances is the computed tomography which helps in the planning, therapy, diagnosis and prognosis of various diseases. The use of CBCT is becoming widespread in dentistry and is applicable both in research and clinical dentistry’s provides a more accurate diagnosis of the endodontic problems which is immensely important for the successful treatment. CBCT can expose additional canals, fractures, extent of canal and any other abnormalities that the 2D radiograph fails to show. The map reading approach can allow the clinicians to easily reduce image evaluation problems as compared to the conventional radiograph diagnosis 5. Since it has obvious advantages over the conventional 2D radiographs interpretation of which can cause errors 5,23. CBCT is a non-destructive technology and renders approvingly accurate, great resolution, cross-sectional and 3D images that are fully computable and consistent. Therefore, Cone beam computed tomography (CBCT) has been advocated for pre- and post-instrumentation evaluation of centring ability of rotary files in root canals 6,7,8. This study was carried out to compare the centring ability of three NiTi rotary file systems. The null hypothesis tested was that there would be no inconsistency among the three-single file NiTi rotary systems considering the investigated parameters. The rotary files picked to carry out the study were HyFlex EDM, Xp Endo Shaper and Wave-one Gold. The canals were prepared according to the manufacturers specifications and then CBCT images were taken at 3mm,6mm and 9mm from the apex to measure the centring ability of the file systems.