title: [Evaluation of the maxillary basal bone and molar change of skeletal Class II malocclusion treated by sagittal-guidance Twin-block].
abstract: OBJECTIVE
  To investigate the effects of sagittal-guidance Twin-block appliance on maxillary basal bone and buccal segment distalization in developing Angle Class II division 1 malocclusion.
  
  
  METHODS
  The measurement data of anterior-posterior direction and vertical dimension between pretherapy and post-treatment, including 34 developing Angle Class II division 1 patients with sagittal-guidance Twin-block and non-extraction treatment, were quantitatively analyzed by X-ray cephalometry and Pancherz. SPSS 20.0 software package was used for statistical analysis.
  
  
  RESULTS
  After orthopedic treatment, the maxilla significantly retruded (0.68 mm, P<0.01), the maxillary molars moved posteriorly (1.33 mm, P<0.01). After orthodontic treatment, the maxillary bone still turned out posteriorly (0.65 mm, P<0.05), and the molar teeth were slightly distalized (0.53 mm, P>0.05).
  
  
  CONCLUSIONS
  The correction of developing Angle Class II division 1 malocclusion can be achieved by sagittal-guidance Twin-block.
authors.affiliation: Department of Orthodontics, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine；Shanghai Key Laboratory of Stomatology. Shanghai 200011, China. E-mail:hehetripleY@163.com.
authors.forename: Ying-Yu
authors.initials: YY
authors.lastname: Yi
authors.forename: Ning
authors.initials: N
authors.lastname: Zhao
authors.forename: Gang
authors.initials: G
authors.lastname: Shen
mesh_terms: D002508:Cephalometry; D006801:Humans; D008312:Malocclusion, Angle Class II; D008334:Mandible; D008437:Maxilla; D008963:Molar; D017289:Orthodontic Appliances, Functional; D014716:Vertical Dimension