title: [Analysis and comparison of dental arch symmetry between different Angle's malocclusion categories and normal occlusion].
abstract: OBJECTIVE
  To analyze and compare dental arch symmetry between different Angle's malocclusion categories and normal occlusion.
  
  
  METHODS
  300 subjects were divided into four different malocclusion groups and normal occlusion group. Data points representing the dental arches on the casts were precisely marked by YM-2115 three Dimension Measuring Machine. Arch forms were fitted with conic sections, and then dental arch symmetry was analyzed by rotation angle.
  
  
  RESULTS
  There were no absolute symmetric dental arch, and the direction of asymmetry was unsteady. In normal occlusion, dental arch was generally symmetric, but there was asymmetry in a very small degree. As to malocclusion, the frequency and degree of dental arch asymmetry were higher than that of normal occlusion, and the lower arch showed more asymmetry than the upper arch except ClassIII. The frequency of asymmetry in ClassII2 and ClassIII groups was higher than that in other malocclusion groups.
  
  
  CONCLUSIONS
  The frequency and degree of dental arch asymmetry were different in different malocclusion groups.
authors.affiliation: Department of Orthodontics, School of Stomatology, Beijing Medical University, Beijing 100081, China.
authors.forename: Q
authors.initials: Q
authors.lastname: Nie
authors.forename: J
authors.initials: J
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D003724:Dental Arch / Q000473:pathology*; D003766:Dental Occlusion; D005260:Female; D006801:Humans; 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