title: A 2D ultrasound evaluation of swallowing in children with unilateral posterior crossbite.
abstract: BACKGROUND
  Swallowing pattern is important in the aetiology of unilateral posterior crossbite (ULCB). The aim of this study was to assess the swallowing pattern and tongue function during swallowing in children with ULCB in deciduous dentition using B-mode and M-mode ultrasonography.
  
  
  METHODS
  Twenty-three children with ULCB, aged 4.1-6.6 years, and 22 children without ULCB, 5.7-6.7 years, were examined with simultaneous B- and M-mode ultrasonography. The swallowing pattern was assessed according to the action of genioglossus muscle in ultrasound images with the scan line of the ultrasound transducer set through the tongue tip. The tongue movements (duration, range, and speed) were compared within each subphase (I, IIa, IIb, IIIa, and IIIb) and in the entire swallowing cycle between the children with ULCB and without ULCB.
  
  
  RESULTS
  The visceral swallowing pattern was found in 83 per cent of children with ULCB and in 36 per cent of children without ULCB; the difference was statistically significant. The duration of phase IIb and the entire swallowing act was found to be statistically significantly prolonged in the ULCB group. Furthermore, the range of the tongue movement in phases and in the entire swallowing act was statistically significantly larger in the ULCB group. The speed of the tongue movement was statistically significantly higher in the ULCB group in phase IIa.
  
  
  CONCLUSIONS
  The 2D ultrasonography was used to evaluate the prevalent type of swallowing in children with ULCB. Visceral type of swallowing pattern and the changed tongue function during swallowing seem to be important factors in the aetiology of ULCB.
authors.affiliation: *Faculty of Medicine, Department of Orthodontics, University of Ljubljana, maja.ovsenik@dom.si.
authors.forename: Maja
authors.initials: M
authors.lastname: Ovsenik
authors.affiliation: *Faculty of Medicine, Department of Orthodontics, University of Ljubljana.
authors.forename: Jure
authors.initials: J
authors.lastname: Volk
authors.affiliation: **Department of Radiology, Institute of Oncology Ljubljana, Slovenia.
authors.forename: Maja Mušič
authors.initials: MM
authors.lastname: Marolt
mesh_terms: D002648:Child; D002675:Child, Preschool; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology*; D014059:Tongue / Q000000981:diagnostic imaging / Q000503:physiopathology; D014094:Tooth, Deciduous; D014463:Ultrasonography