title: Changes in hyoid position following treatment of Class II division1 malocclusions with a functional appliance.
abstract: OBJECTIVE
  The aim of this study was to determine change of hyoid bone position following treatment with functional appliance in patients with class II division 1 malocclusion.
  
  
  METHODS
  This study performed on pre and post treatment lateral cephalograms of 28 patients with class II div I malocclusion treated with Farmand functional appliance on average of 11 months. The range of age of girls was 10-13 years and boys 11-14 years. To study the results, t test and Pearsons correlation coefficient were used.
  
  
  RESULTS
  Hyoid bone shifted significantly (P value < 0.01) forward in horizontal dimension and non significantly upward in vertical dimension. There was no significant difference between three groups in facial growth patterns with respect to hyoid bone position alterations in horizontal dimension but was significant between horizontal and vertical growth pattern in vertical dimension. (P value < 0.05). There was significant correlation between decrease ofANB angle with forward movement of hyoid bone.
  
  
  CONCLUSIONS
  Following treatment with Farmand functional appliance, significant changes occur in the position and anterior displacement of the hyoid bone.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Shahid Sadoghi University of Medical Sciences and Health Services, Yazd, Iran. syassaei@yahoo.com
authors.forename: S
authors.initials: S
authors.lastname: Yassaei
authors.forename: M
authors.initials: M
authors.lastname: Sorush
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005260:Female; D006801:Humans; D006928:Hyoid Bone / Q000033:anatomy & histology* / Q000503:physiopathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000503:physiopathology / Q000628:therapy*; D017289:Orthodontic Appliances, Functional; D009971:Orthodontics, Corrective / Q000295:instrumentation / Q000379:methods; D013284:Stomatognathic System / Q000033:anatomy & histology* / Q000503:physiopathology; D016896:Treatment Outcome; D014716:Vertical Dimension