title: Influence of first premolars extraction on vertical dimension in Italian patients with a Class I normo-divergent malocclusion. A retrospective study.
abstract: OBJECTIVE
  The purpose of this study was to examine the changes in vertical dimension occurring in Class I non-growing patients treated with first four premolars extraction and to test the hypothesis that the vertical dimension collapses after four first premolars extractions.
  
  
  METHODS
  Records of 28 patients (9 males and 19 females) treated with extraction of first four premolars were obtained. Pre-treatment and post-treatment lateral cephalograms were digitized, and 6 linear and 5 angular cephalometric measurements were selected to evaluate vertical changes.
  
  
  RESULTS
  Statistical analysis of the data revealed no significant differences between pre-treatment and post-treatment group. Comparison of the treatment results of the pre-treatment and post-treatment cases showed that there weren't vertical changes following the extraction of first premolars.
  
  
  CONCLUSIONS
  The null hypothesis that premolars extraction results in changes of vertical dimension of occlusion was rejected.
authors.affiliation: Department of Orthodontics, Istituto di II Clinica Odontoiatrica, Policlinico Città Universitaria, Via S. Sofia 78, 95123 Catania, Italy.
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Greco
authors.forename: Grazia
authors.initials: G
authors.lastname: Fichera
authors.forename: Ersilia
authors.initials: E
authors.lastname: Barbato
authors.forename: Rosalia
authors.initials: R
authors.lastname: Leonardi
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000601:surgery; D002508:Cephalometry; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D009971:Orthodontics, Corrective / Q000379:methods*; D012189:Retrospective Studies; D014081:Tooth Extraction; D014716:Vertical Dimension