Root canal shaping is one of the most important steps in canal treatment. It is essential to determine the efficacy of all subsequent procedures, including chemical disinfection and root canal obturation are the basis for successful endodontic endo motor treatment, aiming to debride the root canal, to remove contaminated dentin, and to create an ideal canal shape for three-dimensional filling .
The main objective of a clinician is to mechanically and chemically cleanse the root canal system thoroughly, making it free of microorganisms and their substrates.
The root with a graceful tapering canal and a single apical foramen has long been established as an exception rather than the rule. Bifurcating canals, multiple foramina, fins, deltas, loops, cul-de-sacs, intercanal links, C-shaped canals, and accessory canals have most commonly been faced by the investigators in most teeth .
The instrumentation of the apical matrix to a large size leads to more anatomical irregularities and increases irrigant exchange in the apical third. Apical enlargement during canal cleaning and shaping procedures increases the likelihood of achieving maximum elimination of bacteria from root canal system , though a major part of the canal remains uncleaned even after thorough cleaning and shaping .
Until recently, most investigations have involved counting the number of canals and foramina and categorizing how the canals join or split. Majority of studies have tried to evaluate the shape of the canal systems( root canal treatment equipment ) and its clinical implications than to evaluate the actual preoperative size of the canal .
However, it is recommended not to widen the root canal to a larger extent to avoid unnecessary weakening of the root and increased risk of fracture. Regarding modern concepts, the final canal allows adequate irrigation and close adaptation of the filling material during obturation . Working width (WW) is relatively new concept, which involves perceiving a root canal in both perpendicular (working length) and horizontal (WW) dimensions. Thus, endodontic ―working width‖ has always remained unforgotten dimension during root canal procedure without solid scientific evidence; however, it is still not clear ―how large is enough.