title: Intra-arch widths: a meta-analysis.
abstract: OBJECTIVE
  To determine and compare the mean values of various intra-arch distances in Class I, Class II division 1 and Class II division 2 patients.
  
  
  METHODS
  The search engines PubMed, Embrace and Cochrane were employed to select articles for further study, and the sample thereby selected comprised adult subjects with full permanent dentition, without missing teeth, malformations or previous orthodontic treatment. Only subjects from articles published during the last 10 years were included in the study.
  
  
  RESULTS
  The search located a total of 628 articles regarding arch form. However, only eight articles were chosen for the study. We observed that: the distance between mandibular canines is smaller in Class I than in Class II division 1; mandibular inter-molar distance is similar in Class I and Class II division 1; maxillary inter-canine distance is similar in Class I, Class II division 2 and Class II division 1; maxillary inter-premolar width is greater in Class I than in Class II division 1; and that maxillary inter-molar width is similar in Class I and Class II division 2.
  
  
  CONCLUSIONS
  No statistically significant differences in arch width were found between the different classes analysed (there are only slightly differences between classes), except in the case of mandibular inter-canine width (L3), which was smaller in Class I than in Class II,1, and maxillary inter-premolar width (U4), which was smaller in Class II-I than in Class I.
authors.affiliation: Postgraduate school of Orthodontics, University of Ferrara, via Montebello, 31, Ferrara 44100, Italy. lulombardo@tiscali.it
authors.forename: Luca
authors.initials: L
authors.lastname: Lombardo
authors.forename: Silvia
authors.initials: S
authors.lastname: Setti
authors.forename: Camilla
authors.initials: C
authors.lastname: Molinari
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Siciliani
mesh_terms: D000328:Adult; D003724:Dental Arch / Q000473:pathology*; D006801:Humans; 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