title: Rapid maxillary expansion effects: an alternative assessment method by means of cone-beam tomography.
abstract: BACKGROUND
  This study aims to develop a method to assess the changes in palatal and lingual cross-sectional areas in patients submitted to rapid maxillary expansion (RME).
  
  
  METHODS
  The sample comprised 31 Class I malocclusion individuals submitted to RME and divided into two groups treated with Haas (17 patients) and Hyrax (14 patients) expanders. Cone-beam computed tomography scans were acquired at T0 (before expansion ) and T1 (six months after screw stabilization). Maxillary and mandibular cross-sectional areas were assessed at first permanent molars and first premolars regions and compared at T0 and T1. Mandibular occlusal area was also analyzed.
  
  
  RESULTS
  Maxillary cross-sectional areas increased in 56.18 mm2 and 44.32 mm2 for the posterior and anterior regions. These values were smaller for the mandible, representing augmentation of 40.32 mm2 and 39.91 mm2 for posterior and anterior sections. No differences were found when comparing both expanders. Mandibular occlusal area increased 43.99mm2 and mandibular incisors proclined. Increments of 1.74 mm and 1.7 mm occurred in mandibular intermolar and interpremolar distances. These same distances presented increments of 5.5 mm and 5.57 mm for the maxillary arch.
  
  
  CONCLUSIONS
  Occlusal and cross-sectional areas increased significantly after RME. The method described seems to be reliable and precise to assess intraoral area changes.
authors.affiliation: Rio Verde Valley University.
authors.forename: Camilo Aquino
authors.initials: CA
authors.lastname: Melgaço
authors.affiliation: São José College.
authors.forename: José
authors.initials: J
authors.lastname: Columbano Neto
authors.affiliation: Federal University of Santa Maria.
authors.forename: Estela Maris
authors.initials: EM
authors.lastname: Jurach
authors.affiliation: Federal University of Rio de Janeiro.
authors.forename: Matilde da Cunha Gonçalves
authors.initials: Mda C
authors.lastname: Nojima
authors.affiliation: Federal University of Rio de Janeiro.
authors.forename: Eduardo Franzotti
authors.initials: EF
authors.lastname: Sant'Anna
authors.affiliation: Federal University of Rio de Janeiro.
authors.forename: Lincoln Issamu
authors.initials: LI
authors.lastname: Nojima
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D019412:Anatomy, Cross-Sectional / Q000379:methods; D001641:Bicuspid / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods*; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003724:Dental Arch / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D005500:Follow-Up Studies; D006801:Humans; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008437:Maxilla / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique / Q000295:instrumentation; D010159:Palate / Q000033:anatomy & histology / Q000000981:diagnostic imaging*