title: Comparative analysis of accessory mesial canal identification in mandibular first molars by using four different diagnostic methods.
abstract: BACKGROUND
  The objective of the present in vitro study was to compare 4 diagnostic methods to identify accessory mesial canals (AMCs) in lower first molars.
  
  
  METHODS
  Forty-four lower first molars were selected for assessment with cone-beam computed tomography (CBCT), digital radiography (DR), clinical inspection (CI), and dental operating microscope (DOM). Initially, axial images were obtained by using CBCT, and radiographs were taken in ortho, mesial, and distal angulations. The images were assessed by 2 independent groups of examiners, and all of the results obtained remained undisclosed until the end of the experiment. Subsequently, root canal access was prepared, and the mesial subpulpal groove was located by using sharp endodontic explorers. The roots were examined with DOM, and all identified canals were negotiated and instrumented by using a ProTaper Rotary System. The results were tabulated and statistically analyzed by nonparametric McNemar tests.
  
  
  RESULTS
  Twelve AMCs (27.0%) were identified by CBCT, and 58.0% were instrumented. No AMCs were visualized in any DR examined. Fifteen potential AMCs (34%) were identified by CI, but only 47.0% were confirmed after instrumentation. Thirteen AMCs (30.0%) were identified by DOM, and 84.0% could be negotiated and instrumented.
  
  
  CONCLUSIONS
  There were statistically significant differences between the 4 types of assessments for AMC identification. There was good agreement between DOM and CBCT, whereas DR and CI were not as precise as either of the other 2 diagnostic methods.
authors.affiliation: Department of Dentistry, Pontificial Catholic University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Kênia Maria Pereira Soares
authors.initials: KM
authors.lastname: de Toubes
authors.forename: Maria Ilma de Souza
authors.initials: MI
authors.lastname: Côrtes
authors.forename: Maria Alice de Abreu
authors.initials: MA
authors.lastname: Valadares
authors.forename: Luciana Cardoso
authors.initials: LC
authors.lastname: Fonseca
authors.forename: Eduardo
authors.initials: E
authors.lastname: Nunes
authors.forename: Frank Ferreira
authors.initials: FF
authors.lastname: Silveira
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000592:standards; D003786:Dental Pulp Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D008334:Mandible; D008866:Microsurgery / Q000295:instrumentation / Q000592:standards; D008963:Molar / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D010808:Physical Examination / Q000592:standards; D019252:Radiography, Dental, Digital / Q000592:standards; D018915:Root Canal Preparation / Q000295:instrumentation; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging