title: Treatment effects of twin-block and mandibular protraction appliance-IV in the correction of class II malocclusion.
abstract: OBJECTIVE
  To evaluate the treatment effects of twin-block and Mandibular Protraction Appliance-IV (MPA-IV) in the treatment of Class II division 1 malocclusion.
  
  
  METHODS
  Fifty North Indian girls with Class II division 1 malocclusion, in the age range of 9-13 years, were chosen. The subjects were divided among a control group (n = 10), a twin-block group (n = 25), and an MPA group (n = 15). Pre-follow-up and post-follow-up lateral cephalograms of control subjects and pretreatment and posttreatment lateral cephalograms of the treatment subjects were traced manually and subjected to a pitchfork analysis.
  
  
  RESULTS
  Neither twin-block nor MPA-IV significantly restricted the forward growth of maxilla. Mandibular growth and improvement in the sagittal skeletal relation were significantly greater in the twin-block subjects. Distal movement of the maxillary dentition and mesial movement of the mandibular dentition were more prominent in the MPA-IV subjects. Molar correction and overjet reductions were significantly greater in the treatment subjects (P < .001).
  
  
  CONCLUSIONS
  Twin-block and MPA-IV were effective in correcting the molar relationships and reducing the overjet in Class II division 1 malocclusion subjects. However, twin-block contributed more skeletal effects than MPA-IV for the correction of Class II malocclusion.
authors.affiliation: Oral Health Sciences Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India. ashokkjena@yahoo.co.in
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Jena
authors.forename: Ritu
authors.initials: R
authors.lastname: Duggal
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor / Q000473:pathology; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000628:therapy*; D008334:Mandible / Q000254:growth & development / Q000473:pathology; D019186:Mandibular Advancement / Q000295:instrumentation; D008437:Maxilla / Q000254:growth & development / Q000473:pathology; D008963:Molar / Q000473:pathology; D016382:Orthodontic Appliance Design; D017289:Orthodontic Appliances, Functional; D063173:Retrognathia / Q000473:pathology / Q000628:therapy; D014087:Tooth Movement Techniques / Q000295:instrumentation; D016896:Treatment Outcome