title: Landmark errors on posteroanterior cephalograms.
abstract: BACKGROUND
  It is important to reduce the method errors when evaluating posteroanterior cephalograms to see either small deviations from normal or transverse changes caused by orthodontic treatment. The aim of this study was to determine horizontal and vertical intraexaminer and interexaminer agreement in localization of landmarks in posteroanterior cephalograms of adult patients.
  
  
  METHODS
  The sample was gathered retrospectively from the archives of the Department of Orthodontics of Yeditepe University in Istanbul, Turkey. Radiographs of 39 patients diagnosed with skeletal asymmetries (20 women, 19 men) were drawn manually, and a coordinate system was established with software. The tracings were made by 2 operators, after a calibration session on 29 landmarks (22 bilateral, 7 midline). Intraclass correlation coefficients and the Bland-Altman test were used for detecting interexaminer and intraexaminer agreement for each cephalometric variable.
  
  
  RESULTS
  The interexaminer agreement test showed that the most problematic landmark was crista galli, which showed moderate consistency between 2 examiners in the y coordinates at 2 time points. Condylar and zygomatic landmarks showed good agreement. The greater wing inferior and superior orbit, maxillary point, menton, anterior nasal spine, antegonial notch, mandibular and maxillary molar point, maxillary and mandibular incisor point, and maxillary and mandibular incisor edge landmarks had excellent agreement between the 2 examiners at the 2 time points in both the x and y coordinates.
  
  
  CONCLUSIONS
  There are fewer errors in intraexaminer than in interexaminer correlations in landmark identifications on posteroanterior radiographs. All landmarks investigated except crista galli showed good agreement between measurements.
authors.affiliation: Lecturer, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey. Electronic address: feyza.ulkur@yeditepe.edu.tr.
authors.forename: Feyza
authors.initials: F
authors.lastname: Ulkur
authors.affiliation: Associate professor, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey.
authors.forename: Fulya
authors.initials: F
authors.lastname: Ozdemir
authors.affiliation: Associate professor, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey.
authors.forename: Derya
authors.initials: D
authors.lastname: Germec-Cakan
authors.affiliation: Assistant professor, Department of Biostatistics and Medical Informatics, Department of Medical Education, Yeditepe University, Istanbul, Turkey.
authors.forename: E Cigdem
authors.initials: EC
authors.lastname: Kaspar
mesh_terms: D059925:Anatomic Landmarks; D002508:Cephalometry / Q000379:methods*; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D012189:Retrospective Studies; D012984:Software