title: Cone-beam Computed Tomographic Evaluation and Endodontic Management of a Mandibular First Premolar with Type IX Canal Configuration: Case Report.
abstract: BACKGROUND
  Mandibular premolars exhibit considerable variations in their root canal system that can be particularly difficult to diagnose. Avoiding mishaps and successful nonsurgical endodontic therapy depends on an absolute understanding of the root and root canal morphology to locate, prepare, and obturate the canals.
  
  
  METHODS
  This case report describes the endodontic therapy of a mandibular first premolar with 2 roots and 3 canals with confirmation of cone-beam computed tomography. It also cites the incidence of morphologic variations reported in mandibular first premolars, based on ethnic diversity.
  
  
  RESULTS
  Cone-beam computed tomography (axial and sagittal sections) confirmed the presence of 2 roots and 3 canals in a mandibular first premolar. Here, the main canal divided into 3 root canals at the middle third, otherwise described as Sert and Bayirli's type IX canal configuration.
  
  
  CONCLUSIONS
  The occurrence of documented cases of a mandibular first premolar with Sert and Bayirli's type IX root canal configuration is rare. Failure to recognize a second and third canal in the present case might have otherwise resulted in endodontic reinfection.
authors.affiliation: Muscat, Sultanate of Oman. Electronic address: aaminazoyafarook@gmail.com.
authors.forename: Aamina
authors.initials: A
authors.lastname: Zoya-Farook
authors.affiliation: Muscat, Sultanate of Oman.
authors.forename: Prashant
authors.initials: P
authors.lastname: Abhishek
authors.affiliation: Pearly Whites Dental Clinic, Kolkata, West Bengal, India.
authors.forename: Aditya
authors.initials: A
authors.lastname: Shahabadi
mesh_terms: D000328:Adult; D001641:Bicuspid / Q000002:abnormalities* / Q000000981:diagnostic imaging; D054893:Cone-Beam Computed Tomography; D003786:Dental Pulp Cavity / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008334:Mandible; D011861:Radiography, Dental; D012390:Root Canal Therapy / Q000379:methods*
keywords: CBCT; mandibular first premolar; two roots with three canals; type IX root canal