title: Prediction of Class II improvement after rapid maxillary expansion in early mixed dentition.
abstract: BACKGROUND
  The aim of this study is to identify cephalometric pretreatment parameters for prediction of Class II improvement induced by rapid maxillary expansion.
  
  
  METHODS
  Lateral cephalograms of 30 patients (mean age 8.3 ± 1.6 years old) showing Class II molar relationship and undergone to rapid maxillary expansion on the upper deciduous molars were traced before treatment, and molar relation changes were evaluated on dental casts before and after treatment. Overall treatment time lasted 10.2 ± 2 months. Good responders (18 subjects, 10 females and 8 males) showed improvement of at least 2.50 mm, and bad responders (12 subjects, 7 females and 5 males) showed no improvement, improvement less than 2.50 mm, or worsening of molar relationship after treatment. Student's t test was used to assess significance of differences between groups, and discriminant analysis allowed identification of predictive pretreatment variables.
  
  
  RESULTS
  Articular angle, superior gonial angle, and mandibular dimensions (Co-Gn, S-Ar, Ar-Go, Go-Me) showed significant differences in the comparison between groups. Mandibular length Co-Gn and superior gonial angle were selected as significant predictive variable for discrimination.
  
  
  CONCLUSIONS
  Patients with smaller mandibular length and more acute superior gonial angle are expected to have more chances to improve molar Class II after rapid maxillary expansion.
authors.affiliation: Division of Orthodontics, Department of Surgical and Morphological Sciences, School of Medicine, University of Insubria, Varese, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Caprioglio
authors.affiliation: Division of Orthodontics, Department of Surgical and Morphological Sciences, Orthodontic Programme, School of Medicine, University of Insubria, Varese, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Bergamini
authors.affiliation: Division of Dentistry, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Franchi
authors.affiliation: Department of Surgical and Morphological Sciences, School of Medicine, University of Insubria, Varese, Italy.
authors.forename: Nicolò
authors.initials: N
authors.lastname: Vercellini
authors.affiliation: Department of Surgical and Morphological Sciences, School of Medicine, University of Insubria, Varese, Italy.
authors.forename: Piero Antonio
authors.initials: PA
authors.lastname: Zecca
authors.affiliation: Division of Orthodontics, Department of Medical, Surgical and Health Sciences, University of Messina, Messina, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Nucera
authors.affiliation: Department of Medical, Surgical and Health Sciences, University of Messina, Messina, Italy. rosamariaf@hotmail.it.|C/O Dental School, Via G. Piatti, 10, Velate, 21100, Varese, Italy. rosamariaf@hotmail.it.
authors.forename: Rosamaria
authors.initials: R
authors.lastname: Fastuca
mesh_terms: D002508:Cephalometry; D002648:Child; D003818:Dentition, Mixed; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000628:therapy*; D008963:Molar / Q000473:pathology; D010155:Palatal Expansion Technique; D016896:Treatment Outcome
keywords: Class II malocclusion; Maxillary expansion; Mixed dentition