Background: The objective of this report was to highlight the importance of using a dental operating microscope (DOM) to locate supernumerary canals and diagnose variations in root canals using cone-beam computed tomographic (CBCT) images.
Case Presentation: A 23-year-old male patient had reported with a pain for 1 months and was referred to evaluate symptomatic apical periodontitis for lower right first permanent molar. Root canal therapy was proposed and conducted with the use of DOM and CBCT.