title: Evaluation of airway dimensions and changes in hyoid bone position following class II functional therapy with activator.
abstract: OBJECTIVE
  The aim of this study was to evaluate the long-term effects of Class 2 functional treatment on airway dimensions and positional changes in hyoid bone and compare it with that of an untreated Class 2 control group.
  
  
  METHODS
  Lateral cephalograms of 16 patients (eight girls, eight boys, mean chronological age = 11.36 ± 0.77 years) who were treated with activator and 19 patients (11 girls, eight boys, mean chronological age = 12.14 ± 0.65 years) who served as control were used for linear, angular and area measurements regarding airway track and hyoid bone. Statistics. Intra-group comparisons were performed by paired t-test and Wilcoxon test, whereas independent t-test and Mann Whitney-U were used for inter-group comparisons.
  
  
  RESULTS
  During treatment (T2-T1), nasopharyngeal height and nasopharyngeal area increased (p < 0.05) and hyoid bone moved downward (H-SN; p < 0.001) and forward (H-C3; p < 0.01). During retention period (T3-T2); nasopharyngeal (p < 0.01) and oropharyngeal area increased (p < 0.05). H-SN (p < 0.01) and C3-H distances (p < 0.05) increased. Hyoid bone position exhibited significant changes (H-SN, p < 0.001; C3-H, p < 0.01). The increases in C3-H in long-term was more in the activator group than control (p < 0.05).
  
  
  CONCLUSIONS
  In growing Class 2 patients with mandibular deficiency and airway track without obstructions, functional appliance treatment provided favorable effects on nasopharyngeal and oropharyngeal area throughout the retention period.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Gazi University , Ankara , Turkey.
authors.forename: Cagri
authors.initials: C
authors.lastname: Ulusoy
authors.forename: Nehir
authors.initials: N
authors.lastname: Canigur Bavbek
authors.forename: Burcu Balos
authors.initials: BB
authors.lastname: Tuncer
authors.forename: Cumhur
authors.initials: C
authors.lastname: Tuncer
authors.forename: Cagri
authors.initials: C
authors.lastname: Turkoz
authors.forename: Zeynep
authors.initials: Z
authors.lastname: Gencturk
mesh_terms: D000202:Activator Appliances; D002508:Cephalometry / Q000379:methods; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006928:Hyoid Bone / Q000033:anatomy & histology*; D008297:Male; D008313:Malocclusion, Angle Class III / Q000473:pathology / Q000628:therapy*; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D009295:Nasal Bone / Q000473:pathology; D009305:Nasopharynx / Q000033:anatomy & histology*; D009960:Oropharynx / Q000033:anatomy & histology*; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers; D063173:Retrognathia / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies
keywords: airway; functional therapy; hyoid bone; skeletal Class 2