title: [Effect of jaw forward distance on forced inspiratory airflow in patients with obstructive sleep apnea hypopnea syndrome].
abstract: OBJECTIVE
  To study the effect of different jaw forward distance on forced inspiratory airflow(FIF) in non-apnea subjects and patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and to evaluate the effective jaw forward distance for the treatment of OSAHS with the oral appliance.
  
  
  METHODS
  FIF was measured in 18 non-apnea subjects and 18 OSAHS patients at supine and lateral body positions with different jaw forward distances (the percentages of maximum jaw forward distance): 0%, 25%, 50% and 75%. FIF were converted to percentage values (FIF%, x(-) ± s) followed by averaged. Then the results were analyzed by one-way analysis of variance and paired t-test with α = 0.05.
  
  
  RESULTS
  For non-apnea subjects, there was no significant difference in the FIF values between different jaw forward distances as well as different body positions. For OSAHS patients, the mean FIF% at supine and lateral body positions were 107.1% ± 29.0% and 112.0% ± 33.1% at jaw forward 50%, and were 106.4% ± 20.7% and 116.8% ± 36.4% at jaw forward 75%, respectively, which were significantly higher than those (84.0% ± 18.3% and 98.3% ± 24.0%) at jaw forward 0% or those (92.7% ± 21.8% and 103.7% ± 22.6%) at jaw forward 25%, respectively. But there was no statistical difference in FIF between the two groups of jaw forward 50% and jaw forward 75% and no statistical difference in FIF between supine and lateral body positions in the same forward position.
  
  
  CONCLUSIONS
  Jaw forward 50% is a effective jaw forward distance by oral appliance for the treatment of OSAHS and can improve the airway ventilation in OSAHS patients.
authors.affiliation: Institute of Stomatology, Nanjing Medical University, Nanjing 210029, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Shu
authors.initials: S
authors.lastname: Chen
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.forename: Xiao-meng
authors.initials: XM
authors.lastname: Song
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.forename: Qing-ping
authors.initials: QP
authors.lastname: Zhu
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D006801:Humans; D007320:Inspiratory Capacity; D007568:Jaw / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D055815:Young Adult