title: Dental and skeletal changes in mild to moderate Class II malocclusions treated by either a Twin-block or Xbow appliance followed by full fixed orthodontic treatment.
abstract: To compare the short-term skeletal and dental effects of two-phase orthodontic treatment including either a Twin-block or an XBow appliance.
  
  
  
  This was a retrospective clinical trial of 50 consecutive Class II cases treated in a private practice with either a Twin-block (25) or XBow (25) appliance followed by full fixed orthodontic treatment. To factor out growth, an untreated Class II control group (25) was considered.
  
  
  
  A MANOVA of treatment/observation changes followed by univariate pairwise comparisons showed that the maxilla moved forward less in the treatment groups than in the control group. As for mandibular changes, the corpus length increase was larger in the Twin-block group by 3.9 mm. Dentally, mesial movement of mandibular molars was greater in both treatment groups. Although no distalization of maxillary molars was found in either treatment group, restriction of mesial movement of these teeth was seen in both treatment groups. Both treatment groups demonstrated increased mandibular incisor proclination with larger increases for the XBow group by 3.3°. The Wits value was decreased by 1.6 mm more in the Twin-block group. No sex-related differences were observed.
  
  
  
  Class II correction using an XBow or Twin-block followed by fixed appliances occurs through a relatively similar combination of dental and skeletal effects. An increase in mandibular incisor inclination for the XBow group and an increased corpus length for the Twin-block group were notable exceptions. No overall treatment length differences were seen.
authors.affiliation: a  Private Practice, Vancouver, British Columbia, Canada.
authors.forename: Sayeh
authors.initials: S
authors.lastname: Ehsani
authors.affiliation: b  Private Practice, Edmonton, Alberta, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: Nebbe
authors.affiliation: c  Professor, Faculty of Dentistry, University of Para, Belem, Para, Brazil.
authors.forename: David
authors.initials: D
authors.lastname: Normando
authors.affiliation: d  Assistant Professor, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Manuel O
authors.initials: MO
authors.lastname: Lagravere
authors.affiliation: e  Professor and Head of the Division of Orthodontics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores-Mir
mesh_terms: D000293:Adolescent; D002648:Child; D005147:Facial Bones / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000473:pathology* / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods*; D012189:Retrospective Studies; D014070:Tooth / Q000473:pathology*; D016896:Treatment Outcome
keywords: Cephalometry; Class II division 1 malocclusion; Retrospective clinical trial; Twin-block; XBow