Bilateral symmetry and anatomical root variations of mandibular second molars in North Indian populations using cone beam computed tomography

BACKGROUND: To evaluate bilateral symmetry and anatomical variations of root morphology of permanent mandibular second molar using systematic evaluation of CBCT scans. MATERIAL AND METHODS: This cross-sectional study involved the mandible which were imaged using serial axial cone-beam computed tomography (CBCT) from 680 North Indian patients who visited dental hospital for various reasons unrelated to the study. CBCT Records with presence of bilateral fully erupted permanent mandibular second molars with fully formed apexes were selected. RESULTS: Bilaterally present two root and three canal configurations were most consistently seen (75.88 % and 59.11 %, respectively). The occurrence of two roots with two canals and four canals was 15.14% and 1.61% respectively. Mandibular second molar present with one extra root, radix entomolaris with three canals and four canals was 0.44% and 3.53% while radix paramolaris present with three canals and four canals 1.32% and 1.03% respectively. The occurrence of C-shaped root bilaterally with C shaped canal was 15.88% whereas the presence of one fused root bilaterally was 0.44%. The presence of four roots bilaterally with four canals was identified in only one CBCT scanned image (0.14%). The frequency distribution of root morphology on bilateral symmetrical analysis revealed 98.58 % bilateral symmetry. CONCLUSIONS: In 402 CBCT scans, bilateral presence of two roots with three canals was the most typical root structure seen in mandibular second molars (59.11%). A rare variation found was the presence of four roots occurring bilaterally, seen in only 1 CBCT scan. Bilateral symmetrical analysis of root morphology revealed 98.58 % bilateral symmetry. Key words:Anatomic root variations, mandibular second molar, Cone Beam Computed Tomography scans, bilateral symmetry.