title: Effects of fixed functional therapy on tongue and hyoid positions and posterior airway.
abstract: OBJECTIVE
  To evaluate how therapy with a fixed functional appliance affects airway dimensions, dentoalveolar changes, and tongue and hyoid positions.
  
  
  METHODS
  A retrospective study was carried out on 46 pre- and posttreatment lateral cephalometric radiographs of 23 post-peak Class II patients (12 girls, 11 boys) treated with a Forsus Fatigue Resistant Device (FRD) appliance. The radiographies were taken at the start and at the end of Forsus FRD appliance therapy when a Class I or overcorrected Class I canine and molar relationship was achieved. The process took an average of 5 months 13 days ± 1 month 4 days. Skeletal and dental parameters were measured using Dolphin software, and the sagittal airway area was measured by AutoCAD software.
  
  
  RESULTS
  Analyses of the pre- and posttreatment means revealed that there was no statistically significant skeletal correction of the sagittal malocclusion; increase of lower incisor inclination, decrease of upper incisor inclination, decrease of interincisal angle, and rotation of occlusal plane all contributed to the reduction of overjet. The tongue area and intermaxillary space area increased in response to these dentoalveolar changes; however, there was no statistically significant change in the hyoid position or the oropharyngeal area between the two time points.
  
  
  CONCLUSIONS
  The dentoalveolar changes produced by Forsus FRD appliance did not cause any significant posterior airway changes in young adult patients.
authors.affiliation: a  Associate Professor, Department of Orthodontics, Faculty of Dentistry, Yeditepe University, Istanbul, Turkey.
authors.forename: Fulya
authors.initials: F
authors.lastname: Ozdemir
authors.forename: Feyza
authors.initials: F
authors.lastname: Ulkur
authors.forename: Didem
authors.initials: D
authors.lastname: Nalbantgil
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006928:Hyoid Bone / Q000000981:diagnostic imaging* / Q000473:pathology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007180:Incisor / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy; D009960:Oropharynx / Q000000981:diagnostic imaging* / Q000473:pathology; D016382:Orthodontic Appliance Design; D017289:Orthodontic Appliances, Functional; D057887:Overbite / Q000628:therapy; D011859:Radiography; D012189:Retrospective Studies; D012399:Rotation; D014059:Tongue / Q000000981:diagnostic imaging* / Q000473:pathology; D055815:Young Adult