Endodontic management of middle mesial canal in mandibular first molar

Deviations from the norm such as multiple orifices, apical deltas, accessory canals, and other variations are frequent in the roots of the posterior teeth. Two clinical reports of mandibular molars are presented in which three canals in the mesial roots were treated endodontically. Review of the literature encountered a prevalence ranging from 1% to 15%. Clinically, the third canal is difficult to find and exhibits a very variable morphology, which may present anastomosis with the other canals.