title: Comparative evaluation of molar distalization therapy with erupted second molar: Segmented versus Quad Pendulum appliance.
abstract: BACKGROUND
  There are controversial opinions about the effect of erupted second molars on distalization of the first molars. Most of the distalizing devices are anchored on the first molars, without including second molars; so, differences between sequentially distalize maxillary molars (second molar followed by the first molar) or distalize second and first molars together are not clear. The aim of the study was to compare sequential versus simultaneous molar distalization therapy with erupted second molar using two different modified Pendulum appliances followed by fixed appliances.
  
  
  METHODS
  The treatment sample consisted of 35 class II malocclusion subjects, divided in two groups: group 1 consisted of 24 patients (13 males and 11 females) with a mean pre-treatment age of 12.9 years, treated with the Segmented Pendulum (SP) and fixed appliances; group 2 consisted of 11 patients (6 males and 5 females) with a mean pre-treatment age of 13.2 years, treated with the Quad Pendulum (QP) and fixed appliances. Lateral cephalograms were obtained before treatment (T1), at the end of distalization (T2), and at the end of orthodontic fixed appliance therapy (T3). A Student t test was used to identify significant between-group differences between T1 to T2, T2 to T3, and T1 to T3.
  
  
  RESULTS
  QP and SP were equally effective in distalizing maxillary molars (3.5 and 4 mm, respectively) between T1 and T2; however, the maxillary first molar showed less distal tipping (4.6° vs. 9.6°) and more extrusion (1.1 vs. 0.2 mm) in the QP group than in the SP group, as well as the vertical facial dimension, which increased more in the QP group (1.2°) than in the SP group (0.7°). At T3, the QP group maintained greater increase in lower anterior facial height and molar extrusion and decrease in overbite than the SP group.
  
  
  CONCLUSIONS
  Quad Pendulum seems to have greater increase in vertical dimension and molar extrusion than the Segmented Pendulum.
authors.affiliation: Chairman Postgraduate Programme in Orthodontics, School of Medicine, University of Insubria, Varese, Italy. alberto.caprioglio@uninsubria.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Caprioglio
authors.affiliation: Professor of Orthodontics, School of Medicine, University of Cagliari, Cagliari, Italy. maurocozzani@gmail.com.
authors.forename: Mauro
authors.initials: M
authors.lastname: Cozzani
authors.affiliation: Research Fellow in Orthodontics, University of Insubria, Varese, Italy. mattiafontana16@gmail.com.
authors.forename: Mattia
authors.initials: M
authors.lastname: Fontana
mesh_terms: D000293:Adolescent; D002508:Cephalometry / Q000379:methods; D002648:Child; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008334:Mandible / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology*; D009295:Nasal Bone / Q000473:pathology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation; D016382:Orthodontic Appliance Design; D050793:Orthodontic Extrusion / Q000295:instrumentation; D057887:Overbite / Q000628:therapy; D012658:Sella Turcica / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D016896:Treatment Outcome; D014716:Vertical Dimension
keywords: Class II malocclusion; Intraoral distalizing devices; Molar distalization; Non-compliance; Second molar