title: Effect of orthodontic treatment on the upper airway volume in adults.
abstract: BACKGROUND
  The aim of this study was to examine the effects of orthodontic treatment with and without extractions on the anatomic characteristics of the upper airway in adults.
  
  
  METHODS
  For this retrospective study, the pretreatment and posttreatment cone-beam computed tomography scans of 74 adult patients meeting defined eligibility criteria were analyzed. Imaging software was used to segment and measure upper airway regions including the nasopharynx, the retropalatal, and retroglossal areas of the oropharynx, as well as the total airway. The Wilcoxon signed rank test was used to compare volumetric and minimal cross-sectional area changes from pretreatment to posttreatment.
  
  
  RESULTS
  The reliability values were high for all measurements, with intraclass correlation coefficients of 0.82 or greater. The volumetric treatment changes for the extraction and nonextraction groups were as follows: total airway, 1039.6 ± 3674.3 mm3vs 1719.2 ± 4979.2 mm3; nasopharynx, 136.1 ± 1379.3 mm3vs -36.5 ± 1139.8 mm3; retropalatal, 412.7 ± 3042.5 mm3vs 399.3 ± 3294.6 mm3; and retroglossal, 412.5 ± 1503.2 mm3vs 1109.3 ± 2328.6 mm3. The treatment changes in volume or minimal cross-sectional area for all airway regions examined were not significantly (P >0.05) different between the extraction and nonextraction groups.
  
  
  CONCLUSIONS
  Orthodontic treatment in adults does not cause clinically significant changes to the volume or the minimally constricted area of the upper airway. These results suggest that dental extractions in conjunction with orthodontic treatment have a negligible effect on the upper airway in adults.
authors.affiliation: Assistant professor, Division of Orthodontics, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: pliska@dentistry.ubc.ca.
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Pliska
authors.affiliation: Private practice, Vancouver, British Columbia, Canada.
authors.forename: Isaac T
authors.initials: IT
authors.lastname: Tam
authors.affiliation: Professor and chair, Division of Orthodontics, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Alan A
authors.initials: AA
authors.lastname: Lowe
authors.affiliation: Private practice, Spring Lake Park, Minn.
authors.forename: Alisa M
authors.initials: AM
authors.lastname: Madson
authors.affiliation: Associate professor, Division of Orthodontics, Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Fernanda R
authors.initials: FR
authors.lastname: Almeida
mesh_terms: D000328:Adult; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008297:Male; D009666:Nose / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009960:Oropharynx / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D009971:Orthodontics, Corrective / Q000009:adverse effects*; D010614:Pharynx / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D012137:Respiratory System / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012189:Retrospective Studies