Endodontic management of an atypical permanent mandibular second molar with one buccal and two lingual roots.

This article describes an unusual location of the orifices and roots in a permanent mandibular second molar with symptomatic irreversible pulpitis and symptomatic apical periodontitis. During its micro-endodontic management, the cone-beam computed tomography evaluation revealed a rare variant of a three-rooted permanent mandibular second molar with four canals. The single buccal root had two canals with Vertucci's Type II pattern and a lingual root dividing into two with a single canal in each root, respectively. Interestingly, the concerned tooth had normal occlusal morphology and alignment in the arch. A follow-up of 9 months after the completion of endodontic therapy exhibited satisfactory clinical and radiographic findings.