title: Pharyngeal Airway Space and Hyoid Bone Positioning After Different Orthognathic Surgeries in Skeletal Class II Patients.
abstract: OBJECTIVE
  To obtain good profiles, patients with severe skeletal Class II malocclusion require orthognathic surgery, which might change their airway space and, hence, influence their quality of sleep. The present study aimed to 1) determine the effect of different orthognathic surgeries on pharyngeal airway space and hyoid bone position in patients with skeletal Class II malocclusion and 2) evaluate the stability of changes in the pharyngeal airway space and hyoid bone position after orthognathic surgeries.
  
  
  METHODS
  Patients with severe skeletal Class II malocclusion who underwent mandibular advancement (MA) or mandibular advancement and maxillary setback (MAMS) were included in this retrospective cohort study. Changes in the pharyngeal airway space and hyoid bone position were evaluated as the primary outcome variables. Measurements were obtained before surgery (T1), 1 month after surgery (T2), and 2 years after surgery (T3) using Dolphin Imaging Software 11.0. Differences in measurements between T2 and T1 and between T3 and T1 were calculated and imported into SPSS 22.0 for data analysis.
  
  
  RESULTS
  Fifty patients were included (25 in MA group and 25 in MAMS group). Oropharyngeal and hypopharyngeal airway cross-dimensions and areas were significantly increased in the MA group (P < .05) and the increases were stable at T3. In the MAMS group, the nasopharyngeal airway cross-dimension and area were decreased (P > .05), but the hypopharyngeal cross-dimension and area were significantly increased (P < .05). The hyoid bone moved superiorly and forward after surgery in the MA group (P < .05), and the movement was stable at T3.
  
  
  CONCLUSIONS
  MA can widen the oropharyngeal and hypopharyngeal airway space, and maxillary setback can narrow the nasopharyngeal airway space. Some relapse related to the width of the oropharynx and hypopharynx was found at the long-term observation. The hyoid bone moved superiorly and forward in the MA group.
authors.affiliation: Resident, Key Laboratory of Oral Clinical Medicine, College of Stomatology, Qingdao University; Department of Orthodontics, the Affiliated Hospital of Medical College Qingdao University, Qingdao China; State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Chunmiao
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Resident, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases; Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Yating
authors.initials: Y
authors.lastname: Yi
authors.affiliation: Resident, Department of Prosthodontics, Affiliated Hospital of Medical College Qingdao University, Qingdao, China.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Resident, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases; Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Shanbao
authors.initials: S
authors.lastname: Fang
authors.affiliation: Professor, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases; Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China. Electronic address: wangjunv@scu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D006928:Hyoid Bone / Q000033:anatomy & histology*; D008297:Male; D008312:Malocclusion, Angle Class II / Q000601:surgery*; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D010614:Pharynx / Q000033:anatomy & histology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult