[Changes in shape of upper airway during titrated mandibular advancement: a magnetic resonance imaging study].
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.
Gao
Xue-Mei
XM
Department of Orthodontic, Stomatology School, Peking University, Beijing 100081, China. xmgao@263.net
Otsuka
Ryo
R
Ono
Takashi
T
Honda
Ei-ichi
E
Sasaki
Takehito
T
Kuroda
Takayuki
T
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