title: The time-factor in orthodontics: what influences the duration of treatments in National Health Service practices?
abstract: This study aimed to elucidate factors associated with duration of orthodontic treatment.
  
  
  METHODS
  Retrospective analysis of a systematic 2% sample of cases completed in National Health Service practices in England and Wales. Records were collected during 1991. Characteristics of practitioners, patients, malocclusions, treatment variables and outcomes were evaluated. Data were submitted to multivariate analysis, with Log10 Time in Treatment as the dependent variable.
  
  
  RESULTS
  Data were available for 1506 cases. The (geometric) mean time in treatment was 13 months. A model was found that explained 41% of the variance. Factors found to increase duration were fixed appliances, multiple stages in the treatments, premolar extractions, and correction of antero-posterior buccal occlusion. Age, buccal segment malocclusion, DHC (Dental Health Component of the Index of Orthodontic Treatment Need) grade 5 and orthodontically qualified practitioners were also associated with slightly longer treatments.
  
  
  CONCLUSIONS
  Whilst briefer treatments may be attractive to purchasers, providers and recipients, it should be remembered that thorough treatment, and treatment of more complex malocclusions, tends to take longer. Economic pressures on practitioners to produce high turnovers of cases may be counterproductive in the quest for better outcomes.
authors.affiliation: Department of Dental Medicine and Surgery, Turner Dental School, University of Manchester, and Central Manchester Healthcare NHS Trust, England.
authors.forename: E A
authors.initials: EA
authors.lastname: Turbill
authors.forename: S
authors.initials: S
authors.lastname: Richmond
authors.forename: J L
authors.initials: JL
authors.lastname: Wright
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001641:Bicuspid / Q000601:surgery; D002648:Child; D003149:Community Dentistry; D016001:Confidence Intervals; D003796:Dental Service, Hospital; D004739:England; D005792:General Practice, Dental; D006801:Humans; D016014:Linear Models; D008310:Malocclusion / Q000145:classification / Q000628:therapy; D015999:Multivariate Analysis; D009967:Orthodontic Appliances; D009971:Orthodontics, Corrective / Q000145:classification / Q000379:methods; D010347:Patient Care Planning; D012189:Retrospective Studies; D012690:Serial Extraction; D012923:Social Class; D013222:State Medicine; D013997:Time Factors; D016896:Treatment Outcome; D014852:Wales