Fig. (6) Cone-beam computed tomography scan (axial view) of cervical third of mesiobuccal root canals. A – before preparation. B – after preparation. PTN - ProTaper Next^®; PTG - ProTaper Gold^®; MT - Mtwo^®; BR - BioRaCe^®; WOG - WaveOne Gold^®; REC - Reciproc^®; MB – mesiobuccal canal.