title: Early treatment for Class II Division 1 malocclusion with the Twin-block appliance: a multi-center, randomized, controlled trial.
abstract: BACKGROUND
  The aim of this study was to evaluate the effectiveness of early orthodontic treatment with the Twin-block appliance for the treatment of Class II Division 1 malocclusion. This was a multi-center, randomized, controlled trial with subjects from 14 orthodontic clinics in the United Kingdom.
  
  
  METHODS
  The study included 174 children aged 8 to 10 years with Class II Division 1 malocclusion; they were randomly allocated to receive treatment with a Twin-block appliance or to an initially untreated control group. The subjects were then followed until all orthodontic treatment was completed. Final skeletal pattern, number of attendances, duration of orthodontic treatment, extraction rate, cost of treatment, and the child's self-concept were considered.
  
  
  RESULTS
  At the end of the 10-year study, 141 patients either completed treatment or accepted their occlusion. Data analysis showed that there was no differences between those who received early Twin-block treatment and those who had 1 course of treatment in adolescence with respect to skeletal pattern, extraction rate, and self-esteem. Those who had early treatment had more attendances, received treatment for longer times, and incurred more costs than the adolescent treatment group. They also had significantly poorer final dental occlusion.
  
  
  CONCLUSIONS
  Twin-block treatment when a child is 8 to 9 years old has no advantages over treatment started at an average age of 12.4 years. However, the cost of early treatment to the patient in terms of attendances and length of appliance wear is increased.
authors.affiliation: School of Dentistry, University of Manchester, Manchester, United Kingdom. Kevin.O'Brien@manchester.ac.uk
authors.forename: Kevin
authors.initials: K
authors.lastname: O'Brien
authors.forename: Jean
authors.initials: J
authors.lastname: Wright
authors.forename: Frances
authors.initials: F
authors.lastname: Conboy
authors.forename: Priscilla
authors.initials: P
authors.lastname: Appelbe
authors.forename: Linda
authors.initials: L
authors.lastname: Davies
authors.forename: Ivan
authors.initials: I
authors.lastname: Connolly
authors.forename: Laura
authors.initials: L
authors.lastname: Mitchell
authors.forename: Simon
authors.initials: S
authors.lastname: Littlewood
authors.forename: Nicola
authors.initials: N
authors.lastname: Mandall
authors.forename: David
authors.initials: D
authors.lastname: Lewis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Sandler
authors.forename: Mark
authors.initials: M
authors.lastname: Hammond
authors.forename: Stephen
authors.initials: S
authors.lastname: Chadwick
authors.forename: Julian
authors.initials: J
authors.lastname: O'Neill
authors.forename: Catherine
authors.initials: C
authors.lastname: McDade
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Oskouei
authors.forename: Badri
authors.initials: B
authors.lastname: Thiruvenkatachari
authors.forename: Michael
authors.initials: M
authors.lastname: Read
authors.forename: Stephen
authors.initials: S
authors.lastname: Robinson
authors.forename: David
authors.initials: D
authors.lastname: Birnie
authors.forename: Alison
authors.initials: A
authors.lastname: Murray
authors.forename: Iain
authors.initials: I
authors.lastname: Shaw
authors.forename: Nigel
authors.initials: N
authors.lastname: Harradine
authors.forename: Helen
authors.initials: H
authors.lastname: Worthington
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002508:Cephalometry; D002648:Child; D003362:Cost-Benefit Analysis; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D017289:Orthodontic Appliances, Functional; D009972:Orthodontics, Interceptive / Q000191:economics / Q000295:instrumentation*; D012649:Self Concept; D016896:Treatment Outcome; D006113:United Kingdom