title: Effectiveness of twin-block and Mandibular Protraction Appliance-IV in the improvement of pharyngeal airway passage dimensions in Class II malocclusion subjects with a retrognathic mandible.
abstract: OBJECTIVE
  To test the hypothesis that twin-block and Mandibular Protraction Appliance-IV (MPA-IV) are not effective in improving the pharyngeal airway passage (PAP) dimensions among Class II malocclusion subjects with a retrognathic mandible.
  
  
  METHODS
  Eighty-three subjects ranging in age from 8 to 14 years were divided into four groups. Group I included 30 Class I malocclusion subjects (healthy controls); group II consisted of 16 Class II malocclusion subjects (Class II controls); group III had 16 subjects in whom Class II malocclusion was treated by MPA-IV; and the remaining 21 subjects formed group IV, whose Class II malocclusions were corrected by twin-block appliance. Lateral cephalograms recorded at the beginning of orthodontic treatment in group I subjects and at the beginning and end of follow-up/treatment with functional appliance in group II, III, and IV subjects were analyzed to determine the PAP dimensions. Paired t-test, one-way analysis of variance, and Tukey tests were applied for statistical analysis, and a P-value .05 was considered statistically significant.
  
  
  RESULTS
  Soft palate length was decreased significantly in group III (P < .05) and group IV (P < .001) subjects. Soft palate thickness in group IV subjects was increased significantly as compared to group II (P < .05) and group III (P < .01) subjects. The improvement in soft palate inclination in group III and group IV subjects was significant (P < .01). The oropharynx depth was increased significantly in group III (P < .05) and group IV (P < .001) subjects. The depth of the hypopharynx was increased significantly (P < .01) in group IV subjects.
  
  
  CONCLUSIONS
  The twin-block appliance was more efficient than the MPA-IV in the improvement of PAP dimensions among Class II malocclusion subjects with retrognathic mandible.
authors.affiliation: Unit of Orthodontics, Oral Health Sciences Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India. ashokkjena@yahoo.co.in
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Jena
authors.forename: Satinder Pal
authors.initials: SP
authors.lastname: Singh
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Utreja
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D002680:Chin / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007013:Hypopharynx / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000473:pathology; D019186:Mandibular Advancement / Q000295:instrumentation; D008437:Maxilla / Q000473:pathology; D009960:Oropharynx / Q000473:pathology; D016382:Orthodontic Appliance Design; D017289:Orthodontic Appliances, Functional; D009969:Orthodontic Wires; D010160:Palate, Soft / Q000473:pathology; D010614:Pharynx / Q000473:pathology*; D063173:Retrognathia / Q000628:therapy*; D019291:Skull Base / Q000473:pathology; D016896:Treatment Outcome