title: Comparison of pharyngeal airway dimension, tongue and hyoid bone position based on ANB angle.
abstract: OBJECTIVE
  This study was undertaken to cephalometrically evaluate the pharyngeal airway dimension, tongue and hyoid position in subjects with normal nasorespiratory functions having different dentofacial patterns (A-point-nasion-B-point [ANB] >40 and ANB <40) and to find if a correlation existed.
  
  
  METHODS
  Class I and Class II Division I patients were selected randomly. Lateral head cephalograms were taken in normal head position within a lead foil attached to the tongue tip and a barium coating on the dorsal surface of tongue. The lateral cephalograms obtained were traced using lead acetate paper and measurements were taken. Different analyses were done for the pharyngeal airways, hyoid bone, and tongue.
  
  
  RESULTS
  The ANB angle is a significant predictor for Class I and Class II Division I malocclusion, and the mean ANB angle of Class II Division I was different and higher. The overall mean pharynx and hyoid parameters were different and lower in Class II Division I patients than in Class I patients. The mean tongue parameter almost remained the same except for the tongue position (TT-LOP), which was higher in Class II Division I.
  
  
  CONCLUSIONS
  In general, there was no difference either in the pharyngeal airway anterioposterior dimension or in the position and relationship of the hyoid bone and tongue, between Class I and Class II Division I patients. These findings are consistent with the findings in studies. Anterioposterior dimension of the upper airway is usually maintained by adaptation of both the tongue and the hyoid bone. The result should be viewed in the light of the fact that only anterioposterior dimensions were taken into consideration; the vertical and transverse dimensions of these complex anatomical structures need to have newer three-dimensional (3-D) imaging technique to find if a correlation existed between them, making future studies more comprehensive.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India.
authors.forename: Ashish
authors.initials: A
authors.lastname: Chauhan
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India.
authors.forename: Ram
authors.initials: R
authors.lastname: Autar
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India.
authors.forename: Kusum Lata
authors.initials: KL
authors.lastname: Pradhan
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India.
authors.forename: Vijeta
authors.initials: V
authors.lastname: Yadav
keywords: Class I malocclusion; Class II malocclusion; ImageJ; function; geniohyoid muscle; lateral cephalogram; nasopharynx; nasorespiratory; receiver operating characteristics analysis