title: Reproducibility of maxillofacial anatomic landmarks on 3-dimensional computed tomographic images determined with the 95% confidence ellipse method.
abstract: OBJECTIVE
  To assess the plotting reproducibility of landmarks on 3-dimensional computed tomography (3D-CT) images through use of the 95% confidence ellipse in order to propose sufficiently stable coordinate systems for 3D-CT measurements.
  
  
  METHODS
  Six dentists plotted 19 landmarks twice on 3D-CT images. Scatterplots and the 95% ellipses were produced 3-dimensionally, and the areas of the ellipses were calculated for evaluating the reproducibility of landmarks.
  
  
  RESULTS
  The plotting reproducibility of each landmark showed characteristic features. Among five landmarks (the sella [S], nasion [N], basion [Ba], orbitale [Or], and true porion [Po]) that are frequently used as reference points on cephalograms, Ba showed the smallest areas for all three coordinate axes, indicating high reproducibility. The coronoid process (CP) and the tooth-related landmarks showed relatively high reproducibility.
  
  
  CONCLUSIONS
  Sufficiently stable coordinate axes could be proposed for different treatments and studies.
authors.affiliation: Department of Orthodontics, Aichi-Gakuin University School of Dentistry, Nagoya, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Muramatsu
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nawa
authors.forename: Momoko
authors.initials: M
authors.lastname: Kimura
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Yoshida
authors.forename: Masahito
authors.initials: M
authors.lastname: Maeda
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Katsumata
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Ariji
authors.forename: Shigemi
authors.initials: S
authors.lastname: Goto
mesh_terms: D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D004424:Ear Canal / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005147:Facial Bones / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008963:Molar / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009295:Nasal Bone / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009915:Orbit / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012658:Sella Turcica / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D012886:Skull / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D019291:Skull Base / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*