title: Improvement of nasal airway ventilation after rapid maxillary expansion evaluated with computational fluid dynamics.
abstract: BACKGROUND
  Rapid maxillary expansion is known to improve nasal airway ventilation. However, it is difficult to precisely evaluate this improvement with conventional methods. The purpose of this longitudinal study was to use computational fluid dynamics to estimate the effect of rapid maxillary expansion.
  
  
  METHODS
  Twenty-three subjects (9 boys, 14 girls; mean ages, 9.74 ± 1.29 years before rapid maxillary expansion and 10.87 ± 1.18 years after rapid maxillary expansion) who required rapid maxillary expansion as part of their orthodontic treatment had cone-beam computed tomography images taken before and after rapid maxillary expansion. The computed tomography data were used to reconstruct the 3-dimensional shape of the nasal cavity. Two measures of nasal airflow function (pressure and velocity) were simulated by using computational fluid dynamics.
  
  
  RESULTS
  The pressure after rapid maxillary expansion (80.55 Pa) was significantly lower than before rapid maxillary expansion (147.70 Pa), and the velocity after rapid maxillary expansion (9.63 m/sec) was slower than before rapid maxillary expansion (13.46 m/sec).
  
  
  CONCLUSIONS
  Improvement of nasal airway ventilation by rapid maxillary expansion was detected by computational fluid dynamics.
authors.affiliation: Lecturer, Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. Electronic address: yamame@dent.kagoshima-u.ac.jp.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Iwasaki
authors.affiliation: Assistant professor, Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Saitoh
authors.affiliation: Research associate, Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Takemoto
authors.affiliation: Research associate, Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Inada
authors.affiliation: Private practice, Himeji, Japan.
authors.forename: Ryuzo
authors.initials: R
authors.lastname: Kanomi
authors.affiliation: Professor and chairman, Division of Pediatric Dentistry, Department of Oral Health Science, Course of Oral Life Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
authors.forename: Haruaki
authors.initials: H
authors.lastname: Hayasaki
authors.affiliation: Professor and chairman, Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Yamasaki
mesh_terms: D002648:Child; D019295:Computational Biology; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003724:Dental Arch / Q000473:pathology; D045853:Exhalation / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D057446:Hydrodynamics; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D001239:Inhalation / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male; D008437:Maxilla / Q000473:pathology; D009296:Nasal Cavity / Q000473:pathology / Q000503:physiopathology*; D015508:Nasal Obstruction / Q000473:pathology / Q000503:physiopathology; D009971:Orthodontics, Corrective; D010155:Palatal Expansion Technique; D011312:Pressure; D012123:Pulmonary Ventilation / Q000502:physiology*