title: Longitudinal stability of rapid and slow maxillary expansion.
abstract: OBJECTIVE
  The aim of this retrospective study was to compare the longitudinal stability of two types of posterior crossbite correction: rapid maxillary expansion (RME) and slow maxillary expansion (SME).
  
  
  METHODS
  Study casts of 90 adolescent patients were assessed for interdental width changes at three different periods: pretreatment (T1), post-treatment (T2) and at least, five years post-retention (T3). Three groups of 30 patients were established according to the treatment received to correct posterior crossbite: Group A (RME), group B (SME) and group C (control- Edgewise therapy only). After crossbite correction, all patients received fixed edgewise orthodontic appliances. Paired t-tests and one-way ANOVA were used to identify significant intra and intergroup changes, respectively (P < 0.05).
  
  
  RESULTS
  Except for intercanine distance, all widths increased in groups A and B from T₁ to T₂. In the long-term, the amount of relapse was not different for groups A and B, except for 3-3 widths which showed greater decrease in group A. However, the percentage of clinically relapsed cases of posterior crossbite was similar for rapid and slow maxillary expansion.
  
  
  CONCLUSIONS
  Rapid and slow maxillary expansion showed similar stability in the long-term.
authors: Department of Dentistry, University Potiguar.
authors: Fábio Henrique de Sá Leitão
authors: FH
authors: Pinheiro
authors: Department of Orthodontics, School of Dentistry, University of São Paulo.
authors: Daniela Gamba
authors: DG
authors: Garib
authors: Department of Orthodontics, School of Dentistry, University of São Paulo/Bauru.
authors: Guilherme
authors: G
authors: Janson
authors: Postgraduate program in Orthodontics, Paranaense University.
authors: Roberto
authors: R
authors: Bombonatti
authors: Department of Orthodontics, School of Dentistry, University of São Paulo/Bauru.
authors: Marcos Roberto
authors: MR
authors: de Freitas
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000473:pathology / Q000601:surgery; D002508:Cephalometry / Q000379:methods; D002648:Child; D015331:Cohort Studies; D003481:Cuspid / Q000473:pathology; D003724:Dental Arch / Q000473:pathology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers; D010155:Palatal Expansion Technique / Q000295:instrumentation; D012008:Recurrence; D012189:Retrospective Studies; D014081:Tooth Extraction; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods
references: Am J Orthod. 1970 Jul;58(1):41-66
references: 5269181
references: Angle Orthod. 2003 Aug;73(4):344-53
references: 12940553
references: Angle Orthod. 1980 Jul;50(3):189-217
references: 6996533
references: Am J Orthod. 1981 Oct;80(4):349-65
references: 6945805
references: Am J Orthod. 1983 Jan;83(1):56-61
references: 6336903
references: Am J Orthod. 1982 Dec;82(6):456-63
references: 6961816
references: Am J Orthod Dentofacial Orthop. 1987 Jan;91(1):3-14
references: 3541577
references: Pediatr Dent. 1987 Mar;9(1):65-70
references: 3472189
references: Br J Orthod. 1989 Aug;16(3):195-200
references: 2669948
references: J Clin Orthod. 1991 Apr;25(4):251-64
references: 1939626
references: Fortschr Kieferorthop. 1992 Dec;53(6):344-8
references: 1487219
references: Am J Orthod Dentofacial Orthop. 2005 Sep;128(3):310-25
references: 16168328
references: Am J Orthod Dentofacial Orthop. 2007 Sep;132(3):279.e15-21
references: 17826593
references: Am J Orthod Dentofacial Orthop. 2008 Sep;134(3):383-8
references: 18774084
references: Eur J Orthod. 2009 Apr;31(2):109-20
references: 19304760
references: Angle Orthod. 2010 Jan;80(1):5-9
references: 19852633
references: Angle Orthod. 2004 Aug;74(4):439-49
references: 15387020
references: Am J Orthod Dentofacial Orthop. 1995 Nov;108(5):478-88
references: 7484967
references: Int J Adult Orthodon Orthognath Surg. 1996;11(1):57-66; discussion 67-70
references: 9046628
references: Angle Orthod. 1997;67(4):291-305; discussion 306-8
references: 9267578
references: J Oral Rehabil. 1997 Aug;24(8):614-23
references: 9291256
references: Am J Orthod Dentofacial Orthop. 1999 Jul;116(1):101-7
references: 10393587
references: Rep Congr Eur Orthod Soc. 1964;40:131-42
references: 14318002
references: J Orofac Orthop. 2000;61(2):112-24
references: 10783563
references: Semin Orthod. 1999 Sep;5(3):191-204
references: 10860071
references: Angle Orthod. 2001 Oct;71(5):343-50
references: 11605867
references: Am J Orthod Dentofacial Orthop. 2002 Feb;121(2):129-35; quiz 193
references: 11840125
references: Br J Orthod. 1979 Jan;6(1):25-9
references: 396941