title: Changes in malocclusion over time in New Zealand adolescents.
abstract: BACKGROUND
  The Dental Aesthetic Index (DAI) has been used in many cross-sectional studies of population samples, but its use in assessing changes in malocclusion is less common. The aim of the present study was to describe the natural history of malocclusion and investigate the utility of the DAI as a measure for describing changes in malocclusion in a population-based sample of adolescents.
  
  
  METHODS
  A repeat examination was conducted of a sample of 430 children first assessed in 2003 at age 13 and re-examined at age 16 (255 or 59.3 per cent of the baseline sample) with their DAI and orthodontic history recorded at each age.
  
  
  RESULTS
  Of the adolescents re-assessed, 28 were in active orthodontic treatment, 30 had completed treatment and 197 had not received any treatment. There were substantial changes in the DAI items from age 13 to 16, with the greatest improvement in maxillary anterior irregularity. Overall, almost one-quarter of participants showed an improvement in their DAI treatment need category which was considerably higher among those who had either received treatment or were in treatment.
  
  
  CONCLUSIONS
  The DAI is a valid and responsive tool for measuring change in malocclusion over time. Anterior mandibular irregularity shows the greatest change with age, and orthodontic treatment is effective in treating malocclusion, at least in the short-term.
authors.affiliation: Department of Oral Rehabilitation, Sir John Walsh Research Institute, School of Dentistry, University of Otago, Dunedin, New Zealand. lyndie.fosterpage@otago.ac.nz
authors.forename: Lyndie A Foster
authors.initials: LA
authors.lastname: Page
authors.forename: W Murray
authors.initials: WM
authors.lastname: Thomson
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Quick
mesh_terms: D000293:Adolescent; D000367:Age Factors; D003970:Diastema; D016021:Epidemiologic Studies; D004955:Esthetics, Dental; D005260:Female; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000145:classification / Q000453:epidemiology*; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D009520:New Zealand / Q000453:epidemiology; D024343:Open Bite / Q000453:epidemiology; D009971:Orthodontics, Corrective / Q000706:statistics & numerical data; D057887:Overbite / Q000453:epidemiology; D011159:Population Surveillance; D016388:Tooth Loss / Q000453:epidemiology