title: [Changes in shape of upper airway during titrated mandibular advancement: a magnetic resonance imaging study].
abstract: OBJECTIVE
  To examine adaptive changes in the shape of the upper airway during titrated mandibular advancement. Furthermore, to understand the mechanism of mandible-adjustable therapy to improve the ventilation.
  
  
  METHODS
  Fourteen non-apnea participated in the study. A custom-made oral device was used to keep the mandible in titrated advancement at 0% (F0), 50% (F50), 75% (F75), 100% (F100) of the maximum advancement. Magnetic resonance imaging was used to investigate the difference in the shape of upper-airway in these 4 positions. Changes in the anteroposterior direction (AP), lateral direction (Lat) and its ratio (AP/Lat) were calculated, which were transformed into the percentage of the original ones.
  
  
  RESULTS
  The dose-dependent decrease of AP/Lat was found when the mandible was advanced (P = 0.0001). Lateral change rate in percentage increased by degrees (P = 0.0023), while the increase of anteroposterior change rate in percentage showed no statistical significance.
  
  
  CONCLUSIONS
  The shape of upper airway tended to be less round. The enlargement of upper airway during titrated mandibular advancement was mainly the result of enlargement in lateral direction.
authors.affiliation: Department of Orthodontic, Stomatology School, Peking University, Beijing 100081, China. xmgao@263.net
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Gao
authors.forename: Ryo
authors.initials: R
authors.lastname: Otsuka
authors.forename: Takashi
authors.initials: T
authors.lastname: Ono
authors.forename: Ei-ichi
authors.initials: E
authors.lastname: Honda
authors.forename: Takehito
authors.initials: T
authors.lastname: Sasaki
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kuroda
mesh_terms: D044466:Asian People; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008334:Mandible / Q000033:anatomy & histology*; D019186:Mandibular Advancement; D010160:Palate, Soft / Q000033:anatomy & histology; D010614:Pharynx / Q000033:anatomy & histology