title: Long-term treatment effects of the FR-2 appliance of Fränkel.
abstract: BACKGROUND
  The objective of this study was to evaluate the long-term effectiveness in a group treated with the FR-2 appliance of Fränkel compared with an untreated Class II control group.
  
  
  METHODS
  The sample consisted of 30 patients (17 boys, 13 girls) treated exclusively with the FR-2 by Rolf Fränkel. The mean age at the start of treatment was 8 years (T1), with a posttreatment cephalogram (T2) taken 10 years later. The control group included 20 subjects (11 boys, 9 girls) with untreated Class II malocclusion. Their mean ages at T1 and T2, and the mean times of observation, matched the treatment group closely. Lateral cephalograms were analyzed with a specific tracing regimen at both T1 and T2 in both groups. The Student t test was used to compare changes between the groups
  
  
  RESULTS
  The FR-2 group maintained stable correction of the initial Class II malocclusion over the evaluation period. Significant mandibular and intermaxillary changes and dentoalveolar changes were noted in the treated group, with a 3-mm long-term increase in mandibular length compared with the untreated Class II controls.
  
  
  CONCLUSIONS
  This study suggests that correction of a Class II malocclusion with the FR-2 appliance maintains favorable results over the long term with both skeletal and dentoalveolar changes.
authors.affiliation: University of Michigan, Ann Arbor, MI, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Freeman
authors.forename: James A
authors.initials: JA
authors.lastname: McNamara
authors.forename: Tiziano
authors.initials: T
authors.lastname: Baccetti
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
authors.forename: Christine
authors.initials: C
authors.lastname: Fränkel
mesh_terms: D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000033:anatomy & histology / Q000254:growth & development; D019186:Mandibular Advancement; D017289:Orthodontic Appliances, Functional; D009972:Orthodontics, Interceptive / Q000295:instrumentation*; D016896:Treatment Outcome