A Micro–Computed Tomography Study of the Location and Curvature of the Lingual Canal in the Mandibular First Premolar with Two Canals Originating from a Single Canal

Abstract: Introduction: Little is known about the lingual canal in the Vertucci type V mandibular first premolar. This study investigated the location of the lingual canal orifice and the curvature of the lingual canal by using micro–computed tomography.Methods: One hundred fifteen mandibular first premolars were scanned by micro–computed tomography, reconstructed 3-dimensionally by using Mimics 10.01 software, and displayed in parallel projection mode. Twenty-six teeth with Vertucci type V canal were selected for further study. The lingual canal orifice was located by measurements made in both lingual and proximal views. The angle alpha (α) between the start of the lingual canal and the main canal and the angle beta (β) of the curvature of lingual canal were also measured.Results: In proximal view, 69% of lingual canals were located in the middle third of the tooth and the remainder in the apical third. In lingual view, 73% were located in the middle third of the root and the remainder in the coronal third. Mean angle α and angle β were 33.54° and 26.66°, respectively, in proximal view and 8.31° and 11.31°, respectively, in lingual view (P < .05). The highest values of angles α and β were observed in proximal view (65.24°and 43.39°, respectively). In most cases, angles α and β were severely curved in proximal view and straight or only slightly curved in lingual view.Conclusions: Detailed information on the lingual canal is essential for successful endodontic treatment in patients with mandibular first premolar. The view used for imaging influences the information obtained.