title: A longitudinal study of orthodontic treatment need in Dunedin schoolchildren.
abstract: The Index of Orthodontic Treatment Need (IOTN) was used to assess unmet orthodontic treatment need in 152 13-year-old Dunedin schoolchildren, and to compare the findings with those obtained in the same children 3 years previously. The children were randomly selected from Dunedin schools as 10-year-olds, and had not received orthodontic treatment. Approximately 86 percent of the 13-year-old children had "No-little" need for orthodontic treatment when assessed by the child-assessed Aesthetic Component (AC) and the examiner-assessed AC. Slightly less than half the children had "No-little" need for orthodontic treatment when assessed with the Dental Health Component (DHC). More 10- and 13-year-old children "Needed" orthodontic treatment with the DHC than with the AC. Both the examiner-assessed AC and the DHC assessed significantly fewer 13-year-olds as needing orthodontic treatment than the same children as 10-year-olds. Complete agreement between the grades assigned at 10 and 13 years occurred in 30-43 percent of the children and, in the treatment-need categories, between 53 percent (DHC) and 84 percent (child-assessed AC) of the children. The fall in treatment need over the 3-year period may be due to selection bias, over-sensitivity of the IOTN to mixed dentition traits, or both. Although a number of 10-year-old children were assigned different grades as 13-year-olds, many remained within the same treatment category. The apparent stability of the IOTN to assess treatment need in 10- and 13-year-old children is attributed to the grouping of different occlusal traits in the same treatment-need category, and to the small number of treatment-need categories in each component.
authors.affiliation: Department of Oral Sciences and Orthodontics, School of Dentistry, University of Otago, Dunedin.
authors.forename: J
authors.initials: J
authors.lastname: Chi
authors.forename: M
authors.initials: M
authors.lastname: Harkness
authors.forename: P
authors.initials: P
authors.lastname: Crowther
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001294:Attitude to Health; D016009:Chi-Square Distribution; D002648:Child; D003766:Dental Occlusion; D003818:Dentition, Mixed; D004955:Esthetics, Dental; D005260:Female; D005500:Follow-Up Studies; D006301:Health Services Needs and Demand / Q000706:statistics & numerical data*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000453:epidemiology* / Q000628:therapy; D009520:New Zealand / Q000453:epidemiology; D015588:Observer Variation; D009971:Orthodontics, Corrective / Q000706:statistics & numerical data*; D015983:Selection Bias