title: Does rapid maxillary expansion increase nasopharyngeal space and improve nasal airway resistance?
abstract: OBJECTIVE
  To evaluate the effect of rapid maxillary expansion (RME) on the dimension of the nasopharyngeal space and its relation to nasal airway resistance.
  
  
  METHODS
  Twenty-five school-age children (from 7 to 10 year-old) with mouth and/or mixed breathing, with mixed dentition and uni- or bilateral posterior crossbite involving the deciduous canines and the first permanent molars, were evaluated. RME was placed and remained during 90 days. Rhinomanometry and orthodontic documentation were performed at four different times, i.e., before (T(1)), immediately after (T(2)), 90 days (T(3)) and 30 months (T(4)) after RME.
  
  
  RESULTS
  Differences in nasopharyngeal area and in nasal airway resistance were observed only 30 months after RME, and could be explained by facial growth, and not because of the orthodontic procedure.
  
  
  CONCLUSIONS
  RME does not influence on nasopharyngeal area or nasal airway resistance in long-term evaluation.
authors.affiliation: Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Marjorie Regina Eguren
authors.initials: MR
authors.lastname: Langer
authors.forename: Carla Enoki
authors.initials: CE
authors.lastname: Itikawa
authors.forename: Fabiana Cardoso Pereira
authors.initials: FC
authors.lastname: Valera
authors.forename: Mírian Aiko Nakane
authors.initials: MA
authors.lastname: Matsumoto
authors.forename: Wilma Terezinha
authors.initials: WT
authors.lastname: Anselmo-Lima
mesh_terms: D000403:Airway Resistance / Q000502:physiology*; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000517:prevention & control; D009058:Mouth Breathing / Q000175:diagnosis / Q000628:therapy; D009305:Nasopharynx / Q000033:anatomy & histology* / Q000502:physiology; D010155:Palatal Expansion Technique; D020127:Recovery of Function; D025363:Rhinomanometry; D018570:Risk Assessment; D016896:Treatment Outcome