title: Discriminant factor analysis of dental arch dimensions with 3-dimensional virtual models.
abstract: BACKGROUND
  The form and the size of a dental arch are products of the configuration and the naturally established balance of the jaw, alveolar bone, and muscles. We investigated which arch dimensions mostly discriminate particular dentoalveolar classes and sexes.
  
  
  METHODS
  Plaster dental casts were collected from 137 white adolescent subjects (71 girls, 66 boys) aged between 15 and 18 years (mean, 16.0 ± 1.2 years) with Class I (43 subjects: 24 girls, 19 boys), Class II (50 subjects: 28 girls, 22 boys), and Class III (44 subjects: 19 girls, 25 boys) malocclusions. Casts were scanned with the ATOS II SO (small objects) scanner (GOM mbH, Braunschweig, Germany) and measured with ATOS Viewer software (version 6.0.2; GOM mbH).
  
  
  RESULTS
  The major discriminating factors of the particular dentoalveolar classes are the mandibular canine width/depth ratio and the maxillary molar width/depth ratio, which explain 82.8% of the total variability (P <0.001). Class III subjects with the widest and shallowest frontal segment of the mandibular arch and the posterior segment of maxillary arch are clearly distinguished from Class II subjects whose abovementioned segments are the deepest and narrowest. Class I subjects are more similar to Class II than to Class III subjects. The most homogenous are Class III subjects, with 61.1% of them correctly classified, followed by Class II (57.8%) and Class I (52.4%). Sex differences are significant in linear measurements, but not in ratios.
  
  
  CONCLUSIONS
  Variability of dental arch dimensions and forms is a common characteristic of all dentoalveolar classes. Maxillary arch form is more distinguishing in the posterior segment, and mandibular arch form is more distinguishing in the anterior segment. Class III patients have the most detectable arch form, and Class I the least detectable arch form.
authors: Department of Orthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia. mslaj@sfzg.hr
authors: Martina
authors: M
authors: Slaj
authors: Stjepan
authors: S
authors: Spalj
authors: Damir
authors: D
authors: Jelusic
authors: Mladen
authors: M
authors: Slaj
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000706:statistics & numerical data*; D003481:Cuspid / Q000473:pathology; D003724:Dental Arch / Q000473:pathology*; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008310:Malocclusion / Q000473:pathology*; D008311:Malocclusion, Angle Class I / Q000473:pathology; D008312:Malocclusion, Angle Class II / Q000473:pathology; D008313:Malocclusion, Angle Class III / Q000473:pathology; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D003765:Models, Dental; D008963:Molar / Q000473:pathology; D012737:Sex Factors; D014584:User-Computer Interface