title: Tongue posture improvement and pharyngeal airway enlargement as secondary effects of rapid maxillary expansion: a cone-beam computed tomography study.
abstract: BACKGROUND
  Rapid maxillary expansion (RME) is known to improve nasal airway ventilation. Recent evidence suggests that RME is an effective treatment for obstructive sleep apnea in children with maxillary constriction. However, the effect of RME on tongue posture and pharyngeal airway volume in children with nasal airway obstruction is not clear. In this study, we evaluated these effects using cone-beam computed tomography.
  
  
  METHODS
  Twenty-eight treatment subjects (mean age 9.96 ± 1.21 years) who required RME treatment had cone-beam computed tomography images taken before and after RME. Twenty control subjects (mean age 9.68 ± 1.02 years) received regular orthodontic treatment. Nasal airway ventilation was analyzed by using computational fluid dynamics, and intraoral airway (the low tongue space between tongue and palate) and pharyngeal airway volumes were measured.
  
  
  RESULTS
  Intraoral airway volume decreased significantly in the RME group from 1212.9 ± 1370.9 mm(3) before RME to 279.7 ± 472.0 mm(3) after RME. Nasal airway ventilation was significantly correlated with intraoral airway volume. The increase of pharyngeal airway volume in the control group (1226.3 ± 1782.5 mm(3)) was only 41% that of the RME group (3015.4 ± 1297.6 mm(3)).
  
  
  CONCLUSIONS
  In children with nasal obstruction, RME not only reduces nasal obstruction but also raises tongue posture and enlarges the pharyngeal airway.
authors: Field of Developmental Medicine, Health Research Course, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. yamame@dent.kagoshima-u.ac.japan
authors: Tomonori
authors: T
authors: Iwasaki
authors: Issei
authors: I
authors: Saitoh
authors: Yoshihiko
authors: Y
authors: Takemoto
authors: Emi
authors: E
authors: Inada
authors: Eriko
authors: E
authors: Kakuno
authors: Ryuzo
authors: R
authors: Kanomi
authors: Haruaki
authors: H
authors: Hayasaki
authors: Youichi
authors: Y
authors: Yamasaki
mesh_terms: D000293:Adolescent; D000402:Airway Obstruction / Q000473:pathology / Q000628:therapy*; D000403:Airway Resistance; D019412:Anatomy, Cross-Sectional; D016022:Case-Control Studies; D002508:Cephalometry; D002648:Child; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D057446:Hydrodynamics; D008137:Longitudinal Studies; D008297:Male; D016555:Matched-Pair Analysis; D008437:Maxilla / Q000473:pathology; D009296:Nasal Cavity / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D009971:Orthodontics, Corrective / Q000379:methods; D010155:Palatal Expansion Technique; D010614:Pharynx / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012016:Reference Values; D012189:Retrospective Studies; D014061:Tongue Habits; D016896:Treatment Outcome