title: Three-dimensional analysis of maxillary changes associated with facemask and rapid maxillary expansion compared with bone anchored maxillary protraction.
abstract: BACKGROUND
  Our objectives in this study were to evaluate in 3 dimensions the growth and treatment effects on the midface and the maxillary dentition produced by facemask therapy in association with rapid maxillary expansion (RME/FM) compared with bone-anchored maxillary protraction (BAMP).
  
  
  METHODS
  Forty-six patients with Class III malocclusion were treated with either RME/FM (n = 21) or BAMP (n = 25). Three-dimensional models generated from cone-beam computed tomographic scans, taken before and after approximately 1 year of treatment, were registered on the anterior cranial base and measured using color-coded maps and semitransparent overlays.
  
  
  RESULTS
  The skeletal changes in the maxilla and the right and left zygomas were on average 2.6 mm in the RME/FM group and 3.7 mm in the BAMP group; these were different statistically. Seven RME/FM patients and 4 BAMP patients had a predominantly vertical displacement of the maxilla. The dental changes at the maxillary incisors were on average 3.2 mm in the RME/FM group and 4.3 mm in the BAMP group. Ten RME/FM patients had greater dental compensations than skeletal changes.
  
  
  CONCLUSIONS
  This 3-dimensional study shows that orthopedic changes can be obtained with both RME/FM and BAMP treatments, with protraction of the maxilla and the zygomas. Approximately half of the RME/FM patients had greater dental than skeletal changes, and a third of the RME/FM compared with 17% of the BAMP patients had a predominantly vertical maxillary displacement.
authors.affiliation: Assistant professor, Special Studies in Orthodontics, São Paulo Military Hospital, São Paulo, Brazil.
authors.forename: Claudia Toyama
authors.initials: CT
authors.lastname: Hino
authors.forename: Lucia H S
authors.initials: LH
authors.lastname: Cevidanes
authors.forename: Tung T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Hugo J
authors.initials: HJ
authors.lastname: De Clerck
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
authors.forename: James A
authors.initials: JA
authors.lastname: McNamara
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods; D005115:Extraoral Traction Appliances; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007180:Incisor / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008313:Malocclusion, Angle Class III / Q000628:therapy; D008437:Maxilla / Q000000981:diagnostic imaging / Q000254:growth & development* / Q000473:pathology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods; D014716:Vertical Dimension; D015050:Zygoma / Q000000981:diagnostic imaging / Q000254:growth & development / Q000473:pathology