title: Three-dimensional cephalometric superimposition of the nasomaxillary complex.
abstract: BACKGROUND
  Two-dimensional maxillary superimposition techniques have been routinely used in clinical practice, but a 3-dimensional plane has yet to be introduced and validated. The purposes of this study were to propose a new plane for regional superimposition of the maxillary complex and then to validate it through clinical data.
  
  
  METHODS
  Pretreatment and posttreatment palatal expansion records were used. The magnitudes of the transverse expansion at the levels of the first premolars and the first molars were assessed using the proposed superimposition plane and then were compared with the gold standard plaster model measurements. Descriptive statistics and agreement testing were performed to compare the methods.
  
  
  RESULTS
  When comparing the superimposition and plaster measurement methods, the mean errors for intermolar and interpremolar distances were 0.57 and 0.59 mm, respectively. Both the intraclass correlation coefficient and the Bland-Altman plot demonstrated high agreement between the 2 methods (intraclass correlation coefficient greater than 0.9).
  
  
  CONCLUSIONS
  The proposed maxillary superimposition plane yields clinically suitable results when compared with the gold standard technique, with a mean error of less than 0.6 mm for typical intra-arch measurements. This new landmark-derived maxillary plane for superimposition is a promising tool for evaluating maxillary dentoalveolar changes after treatment.
authors.affiliation: Postgraduate student, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada. Electronic address: glemieux@ualberta.ca.
authors.forename: Genevieve
authors.initials: G
authors.lastname: Lemieux
authors.affiliation: Professor, Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Carey
authors.affiliation: Associate professor and division head, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores-Mir
authors.affiliation: Associate professor, Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Marc
authors.initials: M
authors.lastname: Secanell
authors.affiliation: Surgical resident, McGill University, Montreal, Québec, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Hart
authors.affiliation: Postgraduate student, Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dietrich
authors.affiliation: Associate professor, Orthodontic Graduate Program, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Manuel O
authors.initials: MO
authors.lastname: Lagravère-Vich
mesh_terms: D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D001641:Bicuspid / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000706:statistics & numerical data*; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000706:statistics & numerical data; D003724:Dental Arch / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging*; D003765:Models, Dental; D008963:Molar / Q000000981:diagnostic imaging; D009666:Nose / Q000000981:diagnostic imaging*; D010155:Palatal Expansion Technique; D015203:Reproducibility of Results; D012189:Retrospective Studies