title: Histologic evaluation of human pulp tissue after orthodontic intrusion.
abstract: BACKGROUND
  The forces applied during orthodontic treatment bring about effects on the teeth and surrounding tissues. The aim of this study was to evaluate the possible changes in the human pulpal tissue resulting from orthodontic intrusion in a 21-day period using histologic examination.
  
  
  METHODS
  The sample consisted of 17 young individuals of both sexes between the ages of 12 and 19 years. A total of 34 premolars were evaluated with orthodontic indication of extraction. Because it is a split-mouth study, in each patient, intrusion force of 60 g was applied randomly on 1 of the dental elements experimental group for 21 days. The counterpart control group received no force. After extractions, these dental elements were fixed in 10% formaldehyde, processed automatically, submitted to histotechnical preparation, and stained with hematoxylin-eosin for analysis under optical microscope.
  
  
  RESULTS
  The paired Fisher exact test (P ≤ .05) showed a significant increase of fibrous tissue in the experimental group. The nonparametric paired Wilcoxon test (P ≤ .05) showed a significant increase in the number of pulpal nodules in the elements of the experimental group and showed no difference in the number of blood vessels between the groups. Large-caliber vessels and congested elements were observed in 8 of the experimental group elements.
  
  
  CONCLUSIONS
  The orthodontic intrusion force, in these conditions, caused vascular changes in the pulpal tissue and also increased the presence of fibrosis and the number of pulp calcifications in the experimental elements.
authors.affiliation: Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil. Electronic address: dlazzaretti@ibest.com.br.
authors.forename: Dieison Nardi
authors.initials: DN
authors.lastname: Lazzaretti
authors.affiliation: Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul, Brazil.
authors.forename: Gianna Steffens
authors.initials: GS
authors.lastname: Bortoluzzi
authors.affiliation: Meridional (Southern) Dental Studies Center (CEOM).
authors.forename: Lauren Fioreze
authors.initials: LF
authors.lastname: Torres Fernandes
authors.affiliation: Institute of Pathology of Passo Fundo (IPPF), School of Medicine, University of Passo Fundo (UPF).
authors.forename: Rubens
authors.initials: R
authors.lastname: Rodriguez
authors.affiliation: School of Dentistry, Federal University of Santa Maria (UFSM).
authors.forename: Renésio Armindo
authors.initials: RA
authors.lastname: Grehs
authors.affiliation: Meridional (Southern) Dental Studies Center (CEOM); School of Dentistry IMED.
authors.forename: Mateus Silveira
authors.initials: MS
authors.lastname: Martins Hartmann
mesh_terms: D000293:Adolescent; D001641:Bicuspid / Q000033:anatomy & histology*; D001696:Biomechanical Phenomena; D002648:Child; D004396:Coloring Agents; D003782:Dental Pulp / Q000033:anatomy & histology* / Q000098:blood supply; D003784:Dental Pulp Calcification / Q000473:pathology; D003809:Dentin, Secondary / Q000033:anatomy & histology; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D016591:Histocytological Preparation Techniques; D006801:Humans; D008297:Male; D055806:Microvessels / Q000033:anatomy & histology; D009336:Necrosis; D009804:Odontoblasts / Q000473:pathology; D011671:Pulpitis / Q000473:pathology; D013314:Stress, Mechanical; D014081:Tooth Extraction; D014087:Tooth Movement Techniques / Q000379:methods*; D055815:Young Adult
chemical_list: D004396:Coloring Agents
keywords: Dental pulp; dental pulp calcification; endodontics; orthodontics; pulpitis; tooth movement