title: Asymmetric rapid maxillary expansion in true unilateral crossbite malocclusion: a prospective controlled clinical study.
abstract: OBJECTIVE
  To investigate the short-term effects of the asymmetric rapid maxillary (ARME) appliance on the vertical, sagittal, and transverse planes in patients with true unilateral posterior crossbite.
  
  
  METHODS
  Subjects were divided into two groups. The treatment group was comprised of 21 patients with unilateral posterior crossbite (mean age  =  13.3 ± 2.1 years). Members of this group were treated with the ARME appliance. The control group was comprised of 17 patients with Angle Class I who were kept under observation (mean age  =  12.3 ± 0.8 years). Lateral and frontal cephalograms were taken before the expansion (T1), immediately after expansion (T2), and at postexpansion retention (T3) in the treatment group and at preobservation (T1) and postobservation (T2) in the control group. A total of 34 measurements were assessed on cephalograms. For statistical analysis, the Wilcoxon test and analysis of covariance were used.
  
  
  RESULTS
  The ARME appliance produced significant increases in nasal, maxillary base, upper arch, and lower arch dimensions (P < .01) and a clockwise rotation of the occlusal plane (P  =  .001).
  
  
  CONCLUSIONS
  The ARME appliance created asymmetric increments in the transversal dimensions of the nose, maxilla, and upper arch in the short term. Asymmetric expansion therapy for subjects with unilateral maxillary deficiency may provide satisfactory outcomes in adolescents, with the exception of mandibular arch expansion. The triangular pattern of expansion caused clockwise rotation of the mandible and the occlusal plane and produced significant alterations in the vertical facial dimensions, whereas it created no displacement in maxilla in the sagittal plane.
authors: a Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Selçuk University, Konya, Turkey.
authors: Zehra
authors: Z
authors: Ileri
authors: Faruk Ayhan
authors: FA
authors: Basciftci
mesh_terms: D000293:Adolescent; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D003724:Dental Arch / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000628:therapy*; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D009295:Nasal Bone / Q000473:pathology; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers; D010155:Palatal Expansion Technique / Q000295:instrumentation; D011446:Prospective Studies; D012399:Rotation; D014716:Vertical Dimension
keywords: Dentoalveolar; Rapid maxillary expansion; Skeletal; Soft tissue