title: Skeletal and dentoalveolar effects of Twin-block and bionator appliances in the treatment of Class II malocclusion: a comparative study.
abstract: BACKGROUND
  The purpose of this study was to evaluate the skeletal and dentoalveolar effects of the Twin-block and bionator appliances in the treatment of Class II Division 1 malocclusions.
  
  
  METHODS
  Fifty-five girls from North India with Class II Division 1 malocclusion and the same physical growth maturation status were selected for the study. The subjects were divided among a Twin-block group (n = 25), a bionator group (n = 20), and a control group (n = 10). Pretreatment and posttreatment lateral cephalometric radiographs of the treatment group subjects, and prefollow-up and postfollow-up radiographs of the control group subjects, were traced manually and subjected to the pitchfork analysis.
  
  
  RESULTS
  Statistical software was used for 1-way analysis of variance and multiple comparisons (post-hoc test, Bonferroni). A P value of .05 was considered statistically significant. Neither the Twin-block nor the bionator appliance significantly restricted forward growth of the maxilla (P = .476). Mandibular growth in the Twin-block subjects was significantly greater than in controls (P = .005). Mandibular growth was comparable in the control and the bionator subjects. Molar correction, overjet reduction, and proclination of the mandibular incisors were significantly greater (P = .000) in the treated subjects compared with the controls.
  
  
  CONCLUSIONS
  Both the Twin-block and bionator appliances were effective in correcting molar relationships and reducing overjets in Class II Division 1 malocclusion subjects. However, the Twin-block was more efficient than the bionator in the treatment of Class II Division 1 malocclusion.
authors.affiliation: Division of Orthodontics, Department of Dental Surgery, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India.
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Jena
authors.forename: Ritu
authors.initials: R
authors.lastname: Duggal
authors.forename: Hari
authors.initials: H
authors.lastname: Parkash
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D002508:Cephalometry / Q000706:statistics & numerical data; D002648:Child; D005260:Female; D006801:Humans; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008334:Mandible / Q000254:growth & development; D017289:Orthodontic Appliances, Functional; D009971:Orthodontics, Corrective / Q000295:instrumentation*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome