title: Effect of posterior impaction and setback of the maxilla on retropalatal airway and velopharyngeal dimensions after two-jaw surgery in skeletal Class III patients.
abstract: OBJECTIVE
  To evaluate the changes in retropalatal airway and velopharyngeal dimensions after posterior impaction (PI) only or PI and setback (PI/SB) of the maxilla in patients with skeletal Class III undergoing two-jaw surgery.
  
  
  METHODS
  Subjects consisted of 60 Class III patients treated with two-jaw surgery. They were divided into two groups: group 1 (n  = 30; PI of the maxilla; mean  =  2.6 mm) and group 2 (n = 30; PI/SB of the maxilla; mean  =  2.8 mm and 1.8 mm, respectively). Using three dimensional computed tomography images taken 1month before surgery (T0) and at least 6 months after surgery (T1), retropalatal airway volume, minimum cross-sectional area, and lateral and anteroposterior (AP) dimensions of minimum cross-sectional area, soft palate angle, soft palate length, and pharyngeal depth were measured. A paired t-test and independent t-test were used for statistical analysis.
  
  
  RESULTS
  Group 1 showed increase in retropalatal airway volume and minimum cross-sectional area (P < .01 and P < .05, respectively). Group 2 exhibited decrease in retropalatal airway volume, minimum cross-sectional area, and lateral and AP dimensions of minimum cross-sectional area (all P < .01). Although groups 1 and 2 showed an increase in soft palate length (P < .01 and P < .001, respectively), pharyngeal depth significantly increased only in group 1 (P < .01). Groups 1 and 2 were significantly different in retropalatal airway volume, minimum cross-sectional area, and AP dimension (P < .05, P < .001, and P < .05, respectively).
  
  
  CONCLUSIONS
  Because the direction of surgical movement in the maxilla can determine the changes in the retropalatal airway and velopharyngeal dimensions, it is recommended that clinicians investigate whether patients suffer from sleep-related breathing disorders before performing PI/SB of the maxilla.
authors.affiliation: a  Graduate student (PhD), Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul, South Korea.
authors.forename: Taeyun
authors.initials: T
authors.lastname: Kim
authors.affiliation: b  Professor, Department of Orthodontics, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea.
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
authors.affiliation: c  Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Seoul, South Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D008334:Mandible / Q000033:anatomy & histology; D008437:Maxilla / Q000601:surgery*; D009295:Nasal Bone / Q000033:anatomy & histology; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D010160:Palate, Soft / Q000033:anatomy & histology*; D010614:Pharynx / Q000033:anatomy & histology*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D014609:Uvula / Q000033:anatomy & histology; D055815:Young Adult
keywords: Posterior impaction and/or setback of the maxilla; Retropalatal airway; Sleep-related breathing disorders; Velopharyngeal dimension