title: Assessment of inter- and intra-operator cephalometric tracings on cone beam CT radiographs: comparison of the precision of the cone beam CT versus the latero-lateral radiograph tracing.
abstract: BACKGROUND
  In this study we aimed at quantifying the possible errors which may occur when assessing specific reference planes and linear derivants on cephalometric radiographs traced manually and digitally. Furthermore, we have compared the precision of the tracings according to both the two- and three-dimensional (2D and 3D respectively) techniques and between clinicians.
  
  
  RESULTS
  We have obtained via cone beam computed tomography (CBCT) archive of the orthodontics department of the University of Milan 20 cone beam CT radiographs from which we have obtained 20 latero-lateral radiographs. Five independent clinicians referred to as A, B, C, D, E have been randomly selected to trace both radiographs maintaining the same working and lighting conditions to minimize the possibility of operator- and environment-dependent errors from occurring. The results have been statistically assessed by Student's t test. The comparison of the data gathered from the tracings in 2D and 3D shows that certain measurements have statistically significant differences. Particularly, the difference in the measurements of the sagittal dimension of the mandible and the anterior and posterior nasal spines has resulted to be statistically significant. The results of the intra-operator comparison proved that the 3D technique is extremely precise.
  
  
  CONCLUSIONS
  Our study determines that the 3D technique allows to obtain more precise results and with several advantages when compared to the conventional technique such as a true representation of the anatomical structures, less risk of errors occurring due to clinician skills and absence of overlapping anatomical structures.
authors.affiliation: Orthodontics Department, University of Milan, Milan, Italy. giampietro.farronato@unimi.it.
authors.forename: Giampietro
authors.initials: G
authors.lastname: Farronato
authors.forename: Sara
authors.initials: S
authors.lastname: Salvadori
authors.forename: Francesca
authors.initials: F
authors.lastname: Nolet
authors.forename: Alessandro
authors.initials: A
authors.lastname: Zoia
authors.forename: Davide
authors.initials: D
authors.lastname: Farronato
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods / Q000706:statistics & numerical data*; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000706:statistics & numerical data; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging; D008437:Maxilla / Q000000981:diagnostic imaging; D009295:Nasal Bone / Q000000981:diagnostic imaging; D015588:Observer Variation; D015203:Reproducibility of Results; D012658:Sella Turcica / Q000000981:diagnostic imaging; D019291:Skull Base / Q000000981:diagnostic imaging; D014716:Vertical Dimension