Introduction
pulpitis, perforations, fatigue
PULPITIS, BEND, PULP NECROSIS
Root canal treatment is indicated for primary teeth displaying signs of irreversible pulpitis or pulp necrosis. Biological and mechanical preparation of the root canal is an important step in the removal of microbes and debris from the root canal in primary teeth, like in permanent ones, to provide a pathway for irrigating solutions to reach the apical third of the root canal, which is referred to as chemomechanical preparation, and to achieve a high level of endodontic treatment success.In traditional paediatric endodontics, root canal preparation is performed with hand instruments; however, this manual technique may require long chair time for children. Nickel-titanium (NiTi) files were designed for permanent teeth and were initiated by Barr et al to be used in primary dentition.Recently, paediatric endodontic NiTi rotary file systems have been developed to overcome the difficulties encountered with regular rotary files. Their use allows for safer, convenient root canal preparation; moreover, it minimises the fatigue of the patient and the dental team. On the other hand, the formation of cracks in the root dentin, occurrence of perforations, ledge formation, transportation of canals, and improper taper of the canal preparation are various procedural errors that may arise during the biomechanical preparation of the root canals.The preservation of the original anatomy and the maintenance of the maximum dentin thickness should be maintained during biomechanical preparation, as the instrument should be perfectly balanced centrally in the canal space for reducing the probability of canal transportation.The superelastic properties of NiTi rotary instruments have considerably simplified endodontic treatment. For this reason, NiTi instruments are suitable for the preparation of curved root canals with minimal stress and bend to follow the canal's anatomic curvature, resulting in less canal transportation.Investigators used several methods such as histologic sectioning, radiography, electron microscopy, computed tomography (CT), cone-beam CT (CBCT), micro-CT, and stereomicroscopy to evaluate the shaping abilities of the endodontic instruments. Recently, CBCT has been widely used for the effective assessment of prepared root canals by endodontic instruments.So, this study aimed to evaluate the canal transportation and centring ability of 2 paediatric (Fanta AF baby and Kidzo Elephant) files and one regular rotary file (ProTaper Next) in deciduous molar root canals using CBCT. The null hypothesis was that there is no difference in canal transportation and centring ability between regular and paediatric NiTi rotary files.