title: Micro-CT evaluation of C-shaped mandibular first premolars in a Brazilian subpopulation.
abstract: OBJECTIVE
  To describe morphometric aspects of the internal anatomy of C-shaped mandibular premolars from a Brazilian subpopulation using micro-CT analysis.
  
  
  METHODS
  First mandibular premolars with radicular grooves (n = 123) were scanned using a micro-computed tomography system. After cross-section analysis, 83 specimens were identified with a C-shaped canal and selected for micro-CT analysis. Number and location of canals according to Vertucci's classification, distances between anatomic landmarks, occurrence of apical deltas, furcation canals, prevalence of C-shaped cross-sections at five levels as well as 2-dimensional analysis (Area, perimeter, roundness, aspect ratio, major and minor diameters) were performed for the more prevalent anatomical features. Data were compared statistically using Kruskal-Wallis tests (α = 0.05).
  
  
  RESULTS
  The more prevalent anatomical types according to Vertucci's classification were Type I (13%), III (8%), V (37%) and VII (2%). Mean distances from the furcation to the cemento-enamel junction were in the range of 5.36-5.65 mm. Apical deltas and furcation canals were present in 36 (43%) and 27 (33%) specimens, respectively. C-shaped cross-sections were more prevalent at the middle (56%) and apical middle levels (81%). Overall, significant differences were found in the 2-dimensional analyses between single canals at the apical third and buccal and lingual canals of Vertucci's V classification (P < 0.05).
  
  
  CONCLUSIONS
  In this Brazilian subpopulation, C-shaped canal configuration of the root canal system was found in 67% of extracted first mandibular premolars with radicular grooves. Vertucci's types I and V were the most prevalent anatomical variations. C-shaped cross-sections were more prevalent in the middle third, and the presence of apical deltas was the most common feature in the apical third.
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Ordinola-Zapata
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Monteiro Bramante
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Gagliardi Minotti
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
authors.forename: B
authors.initials: B
authors.lastname: Cavalini Cavenago
authors.affiliation: Department of Endodontics, Baylor College of Dentistry, Texas A&M University System Health Science Center, Dallas, TX, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Gutmann
authors.affiliation: Advanced Education in General Dentistry Program, Larkin Community Hospital, Miami, FL, USA.
authors.forename: B I
authors.initials: BI
authors.lastname: Moldauer
authors.affiliation: Department of Endodontics, Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Versiani
authors.affiliation: Department of Endodontics, Bauru Dental School, University of São Paulo, Bauru, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Hungaro Duarte
mesh_terms: D001641:Bicuspid / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D001938:Brazil; D006801:Humans; D066298:In Vitro Techniques; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D055114:X-Ray Microtomography
keywords: C-shaped canal system; dental anatomy; mandibular premolars; micro-computed tomography