title: Morphologic changes of the palate after rapid maxillary expansion: a 3-dimensional computed tomography evaluation.
abstract: BACKGROUND
  The purpose of this retrospective study was to estimate the area change of the palate after rapid maxillary expansion (RME) in the early mixed dentition stage by using a 3-dimensional (3D) helical computed tomography (CT) scanning technique. In addition, linear changes in the maxillary arch were evaluated.
  
  
  METHODS
  The treated sample consisted of 43 children (mean age, 9 years 1 month) treated with a bonded RME appliance. The untreated control group consisted of 7 children (mean age, 9 years 3 months). Pretreatment and posttreatment dental casts were evaluated by using 3D helical CT scanning procedures. The Student t test was used to compare the linear, area, and angular differences between the treatment times.
  
  
  RESULTS
  RME produced clinically significant increases in interdental widths across the canines, the deciduous first molars, and the permanent first molars in the maxillary arch. Significant increases in cross-sectional area were observed across the permanent first molars (15.3 mm(2)). There was marked variability in the buccal tipping of the permanent first molars.
  
  
  CONCLUSIONS
  Three-dimensional helical CT scanning is an accurate and cost-effective method of assessing dental cast morphologic changes. It can also provide fast and accurate data acquisition and subsequent analysis.
authors.affiliation: Department of Orthodontics, Dental School, University of Western Australia, Nedlands, Western Australia, Australia.
authors.forename: Andriana
authors.initials: A
authors.lastname: Phatouros
authors.forename: Mithran S
authors.initials: MS
authors.lastname: Goonewardene
mesh_terms: D019412:Anatomy, Cross-Sectional; D016022:Case-Control Studies; D002508:Cephalometry / Q000379:methods / Q000706:statistics & numerical data; D002648:Child; D003481:Cuspid / Q000000981:diagnostic imaging; D003724:Dental Arch / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008310:Malocclusion / Q000473:pathology / Q000628:therapy; D008437:Maxilla / Q000000981:diagnostic imaging / Q000473:pathology; D008963:Molar / Q000000981:diagnostic imaging; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique / Q000295:instrumentation; D010159:Palate / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods* / Q000706:statistics & numerical data; D014094:Tooth, Deciduous / Q000000981:diagnostic imaging