title: Three-dimensional computed tomography analysis of airway volume changes between open and closed jaw positions.
abstract: BACKGROUND
  Airway dimensions are closely linked to the bone and soft-tissue craniofacial anatomy. Reduction of the airway is seen with airway disorders and can impair function. The purpose of this retrospective study was to determine whether changing from open to closed jaw position affects the volume of the nasal cavity, nasopharynx, and oropharynx; the soft palate; the soft-tissue thickness of the airway; and the most constricted area of the airway.
  
  
  METHODS
  Following reliability studies, in this retrospective study, we analyzed cone-beam computed tomography scans taken in both closed and open jaw positions of 60 subjects who were undergoing diagnosis and treatment of temporomandibular disorders. On each scan, condyle-fossa measurements, volumes of airway segments (nasal cavity, nasopharynx, oropharynx), soft palate areas, soft tissue thicknesses of the airway, and the most constricted area of the airway and its location were measured using Dolphin imaging software (version 11.5; Patterson Dental Supply, Chatsworth, Calif). Differences between the 2 jaw positions were analyzed with paired t tests, accepting P ≤0.05 as significant.
  
  
  RESULTS
  Significant changes in airway dimensions were found between the closed and open jaw positions. With jaw opening, the nasopharynx volume increased, whereas the oropharynx volume decreased. Significant decreases were also found for measurements of basion to posterior airway wall, cervical vertebrae to posterior airway wall, most constricted area, nasal cavity volume, and soft palate area when the jaw was open.
  
  
  CONCLUSIONS
  Changing jaw position significantly affects airway dimensions.
authors.affiliation: Orthodontic resident, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: Leslie
authors.initials: L
authors.lastname: Glupker
authors.affiliation: Chair and Jarabak Endowed Professor, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kula
authors.affiliation: Professor, Department of Oral Pathology, Medicine and Radiology, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: Edwin
authors.initials: E
authors.lastname: Parks
authors.affiliation: Acting chairman, Department of Oral Biology, School of Dentistry, Indiana University, Indianapolis, Ind; associate professor of anatomy, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: William
authors.initials: W
authors.lastname: Babler
authors.affiliation: Assistant professor, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: Kelton
authors.initials: K
authors.lastname: Stewart
authors.affiliation: Assistant professor, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University, Indianapolis, Ind; lecturer, Department of Orthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt. Electronic address: aghoneim@iu.edu.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Ghoneima
mesh_terms: D000328:Adult; D002508:Cephalometry / Q000379:methods; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008334:Mandible / Q000502:physiology*; D008875:Middle Aged; D009296:Nasal Cavity / Q000000981:diagnostic imaging; D009305:Nasopharynx / Q000000981:diagnostic imaging; D009960:Oropharynx / Q000000981:diagnostic imaging; D010160:Palate, Soft / Q000000981:diagnostic imaging; D010614:Pharynx / Q000000981:diagnostic imaging*; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging; D055815:Young Adult