title: Effects of cervical headgear and fixed appliances on the space available for maxillary second molars.
abstract: BACKGROUND
  This study examined the effects of cervical headgear and fixed appliances on the space available for the eruption of the maxillary second molars. Cervical headgear was the only intervention until a Class I molar relationship was achieved.
  
  
  METHODS
  Thirty-four patients (18 girls, 16 boys) with Class II molar occlusions, treated without extractions, were included in this study. Five linear and 4 angular cephalometric measurements were made from pretreatment and posttreatment radiographs.
  
  
  RESULTS
  Treatment prevented the mesial drift of the maxillary first permanent molars and the forward displacement of the maxilla, displaced the pterygomaxillary fissure posteriorly, and uprighted the first permanent molars. In the male group, the only significant changes were molar uprighting and clockwise rotation of the maxilla.
  
  
  CONCLUSIONS
  These results suggest that posterior displacement of the pterygomaxillary fissure by treatment and growth at the maxillary tuberosity compensated for the restricted anterior movement of the maxillary first molars, allowing the second molars to erupt.
authors.affiliation: Department of Orthodontics, School of Dentistry, Pontifícia Universidade Católica, Minas Gerais, Brazil.
authors.forename: Leandro M
authors.initials: LM
authors.lastname: Piva
authors.forename: Hélio H A
authors.initials: HH
authors.lastname: Brito
authors.forename: Heloísio R
authors.initials: HR
authors.lastname: Leite
authors.forename: Maria
authors.initials: M
authors.lastname: O'Reilly
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005115:Extraoral Traction Appliances; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008437:Maxilla; D008445:Maxillofacial Development; D008963:Molar / Q000254:growth & development*; D009333:Neck; D009972:Orthodontics, Interceptive / Q000295:instrumentation* / Q000379:methods; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014078:Tooth Eruption