title: Rapid maxillary expansion: effects on palatal area investigated by computed tomography in growing subjects.
abstract: OBJECTIVE
  The aim of this prospective study was to evaluate the effects of rapid maxillary expansion (RME) on the palatal area as assessed by low-dose CT before treatment (T0), at the end of active expansion (T1) and after a retention period of 6 months (T2).
  
  
  METHODS
  The study sample comprised 17 prepubertal subjects (mean age 11.2 years) with constricted maxillary arches. Total amount of expansion was 7 mm in all subjects. Multi-slice low-dose CT scans were taken at T0, T1, and T2. On axial CT scanned images a circle line corresponding to the palatal area was drawn and the area inside the circle registered at all three observation times. The area was measured in mm². Statistical comparisons were carried out with Friedman test with post-hoc tests (P<0.05).
  
  
  RESULTS
  The palatal area showed a significant increase from T0 to T1 and from T0 to T2 as a consequence of the opening of the midpalatal suture after RME.
  
  
  CONCLUSIONS
  Opening the midpalatal suture by using orthopedic forces allowed to extend the area of the maxilla. After a 6-months retention period the palatal area demonstrated a stable increase due to a bone deposition along the midpalatal suture in both the anterior and posterior parts of the maxilla.
authors.affiliation: Department of Orthodontics, University of Rome Tor Vergata, Rome, Italy. robertalione@yahoo.it
authors.forename: R
authors.initials: R
authors.lastname: Lione
authors.forename: C
authors.initials: C
authors.lastname: Pavoni
authors.forename: G
authors.initials: G
authors.lastname: Laganà
authors.forename: E
authors.initials: E
authors.lastname: Fanucci
authors.forename: L
authors.initials: L
authors.lastname: Ottria
authors.forename: P
authors.initials: P
authors.lastname: Cozza
mesh_terms: D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D010155:Palatal Expansion Technique; D021362:Palate, Hard / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed