title: Oral appliance effectively reverses Muller's maneuver-induced upper airway collapsibility in obstructive sleep apnea and hypopnea syndrome.
abstract: OBJECTIVE
  To verify the effects of oral appliance (OA) on upper airway morphology under intraluminal pressure, identify specific sites of upper airway collapsibility that can be reversed by OAs, and determine the relationship between OA efficacy and dynamic upper airway changes using computed tomography (CT) with Muller's maneuver.
  
  
  METHODS
  Nineteen adult Chinese patients with symptomatic mild-to-moderate sleep apnea were recruited from our sleep center. Each patient was fitted with a two-piece OA. Dynamic changes in the retropalatal and retroglossal airway were evaluated using CT at end-expiration and during Muller's maneuver, both with and without an OA.
  
  
  RESULTS
  Upper airway changes in the end-expiration phase before OA placement did not significantly differ from those after OA placement. However, under intraluminal pressure induced by Muller's maneuver, OA effectively expanded the upper airway at multiple levels. In addition, OA counteracted negative intraluminal pressure more effectively in the retropalatal region than in the retroglossal region, with 95.65, 68.75, 72.41, and 78.38 % improvements in the collapsibility index of the anteroposterior dimension, transverse dimension, minimum cross-sectional area, and volume of the retropalatal region, respectively. Both nonresponders and responders to OA treatment were sensitive to the intraluminal pressure induced by Muller's maneuver. However, the collapsibility of the retropalatal airway improved significantly only in the responders, not in the nonresponders.
  
  
  CONCLUSIONS
  OA effectively treats OSAHS by improving upper airway collapsibility.
authors.affiliation: Department of Oral and Cranio-Maxillofacial Science, Shanghai Ninth People's Hospital, School of Stomatology, Shanghai Key Laboratory of Stomatology, Shanghai Jiao Tong University School of Medicine, No. 639 Zhi Zao Ju Rd, 200011, Shanghai, China.
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Zhao
authors.forename: Huimin
authors.initials: H
authors.lastname: Shi
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Lu
authors.forename: Jindong
authors.initials: J
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Nie
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Tang
authors.forename: Li
authors.initials: L
authors.lastname: Tao
authors.forename: Min
authors.initials: M
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000402:Airway Obstruction / Q000175:diagnosis* / Q000628:therapy*; D001274:Atmospheric Pressure; D045853:Exhalation; D005260:Female; D006801:Humans; D008297:Male; D019186:Mandibular Advancement / Q000295:instrumentation*; D008875:Middle Aged; D017090:Occlusal Splints; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000628:therapy*; D054894:Spiral Cone-Beam Computed Tomography; D016896:Treatment Outcome