Management of Complex Root Canal Curvature of Bilateral Radix Entomolaris: Three-Dimensional Analysis with Cone Beam Computed Tomography

The meticulous knowledge of anatomic characteristics and their variations is essential for the clinician. Radix entomolaris (RE) is one such anomaly where an extra root is present on the distolingual aspect of the mandibular first molar. 18-year-old patient was referred for the root canal treatment of mandibular right and left first molars. Intraoral periapical radiograph revealed additional periodontal spacing crossing distal root of 36. A CBCT was advised and it confirmed the presence of extra roots both in 36 and 46. CBCT is useful in endodontics as it aids in the identification of essential anatomic structures and determination of radius and angle of root canal curvature which is linked to fracture of the instrument. The classical triangular access cavity was modified to a trapezoidal form to locate the extra canal. All canals were instrumented with controlled memory nickel titanium instruments and obturation was done with single cone technique. 1. Introduction Success of endodontic therapy depends on the complete cleaning and shaping of the root canal systems, tridimensional obturation, and proper coronary sealing. For that purpose, the knowledge of the morphology of the root canal system as well as its variations is essential. The mandibular first molar is known to display several anatomical variations. The number of roots may also vary in mandibular molars, in which a third additional root, firstly mentioned in the literature by Carabelli [1], is called radix entomolaris. This supernumerary root is located in distolingual position, mainly in the mandibular first molars. When located in the mesiobuccal surface, the anomaly is called radix paramolaris [2]. The frequency of radix entomolaris is less than 5% in Caucasian, African, Eurasian, and Indian populations [3], whereas its bilateral occurrence is less than 2.19% [4]. This extra root is typically smaller and more sharply curved than the distobuccal (DB) root, requiring special attention when root canal treatment is being considered. CBCT is a noninvasive technique to determine the occurrence of distolingual root and reveals the true nature of macrostructure three-dimensionally and its curvature and angulation [5]. CBCT shows the exact position of distolingual root and hence it helps in tracking the curvature and prevents iatrogenic event that might occur in relation to canal curvature like instrument separation, perforation, ledge formation, and so forth. 2. Case Presentation 18-year-old male patient reported to the dental office with the chief complaint of swelling in lower left back region