title: Cephalometric landmark variability among orthodontists and dentomaxillofacial radiologists: a comparative study.
abstract: OBJECTIVE
  The aim this study was to compare the accuracy of orthodontists and dentomaxillofacial radiologists in identifying 17 commonly used cephalometric landmarks, and to determine the extent of variability associated with each of those landmarks.
  
  
  METHODS
  Twenty digital lateral cephalometric radiographs were evaluated by two groups of dental specialists, and 17 cephalometric landmarks were identified. The x and y coordinates of each landmark were recorded. The mean value for each landmark was considered the best estimate and used as the standard. Variation in measurements of the distance between landmarks and measurements of the angles associated with certain landmarks was also assessed by a subset of two observers, and intraobserver and interobserver agreement were evaluated.
  
  
  RESULTS
  Intraclass correlation coefficients were excellent for intraobserver agreement, but only good for interobserver agreement. The least reliable landmark for orthodontists was the gnathion (Gn) point (standard deviation [SD], 5.92 mm), while the orbitale (Or) was the least reliable landmark (SD, 4.41 mm) for dentomaxillofacial radiologists. Furthermore, the condylion (Co)-Gn plane was the least consistent (SD, 4.43 mm).
  
  
  CONCLUSIONS
  We established that some landmarks were not as reproducible as others, both horizontally and vertically. The most consistently identified landmark in both groups was the lower incisor border, while the least reliable points were Co, Gn, Or, and the anterior nasal spine. Overall, a lower level of reproducibility in the identification of cephalometric landmarks was observed among orthodontists.
authors.affiliation: Department of Dental Radiology, Faculty of Dental Medicine, University of Porto, Porto, Portugal.
authors.forename: Ana Paula Reis
authors.initials: AP
authors.lastname: Durão
authors.affiliation: Department of Surgery, Dentistry School, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Morosolli
authors.affiliation: Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Pisha
authors.initials: P
authors.lastname: Pittayapat
authors.affiliation: Department of Clinical Dentistry, Faculty of Health Science, UiT The Arctic University of Norway, Tromsø, Norway.
authors.forename: Napat
authors.initials: N
authors.lastname: Bolstad
authors.affiliation: Department of Orthodontics, Faculty of Dental Medicine, University of Porto, Portugal.
authors.forename: Afonso P
authors.initials: AP
authors.lastname: Ferreira
authors.affiliation: Oral Imaging Center, OMFS-IMPATH Research Group, Department of Imaging and Pathology, Faculty of Medicine, University of Leuven, Leuven, Belgium.
authors.forename: Reinhilde
authors.initials: R
authors.lastname: Jacobs
keywords: Analysis; Anatomic Landmarks; Cephalometry; Orthodontics; Reliability and Validity