Biomechanical preparation is one of the most important steps of primary teeth pulpectomy, which are primarily targeted during canal debridement . Conventionally, hand files were used for cleaning and shaping in primary teeth with some disadvantages such as time wastage and the occurrence of iatrogenic errors such as zipping, lateral perforations, apical obstruction, and canal transportation.~The use of rotary instruments for primary tooth instrumentation is faster, affordable, and yields consistent, reliable results. Numerous rotary endodontic systems designed primarily for application in permanent teeth, have been suggested for primary teeth root canal preparation. Since the primary teeth have a ribbon-shaped anatomy and shorter, thinner curved roots than permanent teeth, the use of these files in pulpectomy of primary teeth could produce lateral perforations. As a result, there was a great need for the development of a unique pediatric rotary file system.~The Kedo-S Square rotary system is a single file system specifically designed for paediatric use. It consists of two files, one for anterior primary teeth (A1) and one for posterior primary teeth (P1) also, Fanta AF™-Baby rotary system, another specifically generated paediatric rotary file, was produced using Ni-Ti controlled memory (CM)-Wire technology.~A good root canal treatment in primary teeth is dependent on the quality of biomechanical preparation, the type of obturating material used with as few voids as possible, and the achievement of a good hermetic seal. Also, treatment time is an important aspect as reduced chairside time increases children's cooperation for dental treatment, reduces anxiety, and making the treatment protocol optimal. Another factor affecting the success of primary teeth pulpectomy is the postoperative pain which may be due to extrusion of foreign particles into peri-radicular tissues accordingly, causing inflammation and releasing inflammatory mediators.
Manual files used for the pulpectomy of primary teeth have some disadvantages such as time wastage and the occurrence of iatrogenic errors compared to rotary systems.~Little studies have been done to clinically evaluate the Kedo-S Square & Fanta AF™ Baby rotary systems in relation to the quality of obturation, instrumentation time and postoperative pain in root canal preparation of primary molars using CBCT.