title: Linear mandibular measurements: comparison between orthopantomograms and lateral cephalograms.
abstract: OBJECTIVE
  To investigate the reliability of length measurements of the mandible by comparing orthopantomograms (OPTs) with lateral cephalograms.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  OPTs and lateral cephalograms were taken of 20 human dry skulls. Four orthodontists and four maxillofacial surgeons located landmarks on all radiographs using a computer program for cephalometric measurements. Intraobserver and interobserver variability in locating landmarks was assessed, as well as positioning of the skulls prior to radiography between the x-ray assistants. Magnification differences between the left and right side of the mandible on the OPT were determined for five skulls. Kappa statistics were used to calculate the intraclass correlation coefficient for intraobserver and interobserver differences. An F test was used to assess differences between methods and between type of observer.
  
  
  RESULTS
  No significant differences were found in the magnification factor of the left and right side of the mandible. Compared with a lateral cephalogram, the OPT had comparable reliability in measuring mandibular distances condylion-gonion, gonion-menton, and condylion-menton. No significant differences were observed between the x-ray assistants in taking the OPTs and lateral cephalograms or in repositioning the skulls. Significant differences were found between orthodontists and maxillofacial surgeons for landmark measurements.
  
  
  CONCLUSIONS
  An OPT is as reliable as a lateral cephalogram for linear measurements of the mandible (condylion-gonion, gonion-menton, and condylion-menton).
authors.affiliation: Erasmus MC, University Medical Center, Rotterdam, the Netherlands. e.ongkosuwito@erasmusmc.nl
authors.forename: E M
authors.initials: EM
authors.lastname: Ongkosuwito
authors.forename: M M J
authors.initials: MM
authors.lastname: Dieleman
authors.forename: A M
authors.initials: AM
authors.lastname: Kuijpers-Jagtman
authors.forename: P G H
authors.initials: PG
authors.lastname: Mulder
authors.forename: J W
authors.initials: JW
authors.lastname: van Neck
mesh_terms: D002508:Cephalometry / Q000706:statistics & numerical data*; D002680:Chin / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008334:Mandible / Q000000981:diagnostic imaging*; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D015588:Observer Variation; D009970:Orthodontics / Q000706:statistics & numerical data; D011858:Radiographic Magnification / Q000706:statistics & numerical data; D011862:Radiography, Panoramic / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012984:Software; D013515:Surgery, Oral / Q000706:statistics & numerical data