title: Comparative evaluation of mandibular canal visibility on cross-sectional cone-beam CT images: a retrospective study.
abstract: OBJECTIVE
  The purpose of this study was to determine the visibility of the mandibular canal (MC) in CBCT images and if the visibility of the MC is affected by gender, location and/or age.
  
  
  METHODS
  CBCT images were evaluated for the visibility of the MC by a board-certified oral and maxillofacial radiologist, a board-certified periodontist and a periodontics resident. Representative slices were examined for the first premolar (PM(1)), second premolar (PM(2)), first molar (M(1)) and second molar (M(2)) sites by all examiners. The visibility of the MC was registered as either present or absent.
  
  
  RESULTS
  360 total CBCT cross-sectional images were examined, with the MC identified in 204 sites (56%). Age had a significant effect on MC visibility, but it differed by location: for PM(1), age 47-56 had lower visibility than age 65+ (p = 0.0377). Gender also had a significant effect on canal visibility, where females had lower visibility than males overall (p = 0.0178) and had the most pronounced difference for PM(1) (p = 0.0054). Location had a significant effect on visibility, but it differed by age and by gender: for age 65+, M(2) had lower visibility than PM(1) (p = 0.0411) and PM(2) (p = 0.0180), while for females, PM(1) had lower visibility than M(1) (p = 0.0123) and M(2) (p = 0.0419).
  
  
  CONCLUSIONS
  The MC was visualized only in just over half of the CBCT images. Age, gender and location had significant effects on the visibility.
authors.affiliation: 1 Department of Periodontics and Allied Dental Programs, Indiana University School of Dentistry, Indianapolis, IN, USA.
authors.forename: Mahogany S
authors.initials: MS
authors.lastname: Miles
authors.affiliation: 2 Department of Oral Maxillofacial Radiology, Medicine and Pathology, Indiana University School of Dentistry, Indianapolis, IN, USA.
authors.forename: Edwin T
authors.initials: ET
authors.lastname: Parks
authors.affiliation: 3 Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: George J
authors.initials: GJ
authors.lastname: Eckert
authors.affiliation: 1 Department of Periodontics and Allied Dental Programs, Indiana University School of Dentistry, Indianapolis, IN, USA.
authors.forename: Steven B
authors.initials: SB
authors.lastname: Blanchard
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019412:Anatomy, Cross-Sectional / Q000379:methods*; D001641:Bicuspid / Q000000981:diagnostic imaging; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging*; D008875:Middle Aged; D008963:Molar / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D012737:Sex Factors; D055815:Young Adult
keywords: cone-beam CT; dental implants; diagnostic imaging; mandible; radiology