title: Orthodontic force increases interleukin-1β and tumor necrosis factor-α expression and alveolar bone loss in periodontitis.
abstract: BACKGROUND
  The present study aims to evaluate the effects of orthodontic movement (OM) on the periodontal tissues of rats with ligature-induced periodontal disease.
  
  
  METHODS
  Eighty-eight rats were divided into four groups: 1) negative control (sham operated); 2) periodontal disease; 3) OM; and 4) periodontal disease followed by OM (OMP). Rats were sacrificed 3 hours or 1, 3, or 7 days after OM commencement. Bone volume fraction (BVF) and bone mineral density (BMD) were assessed in hemimaxillae by microcomputed tomography analysis. Expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α were evaluated in gingival samples by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, and in the furcation region by immunohistochemistry analysis (IHC).
  
  
  RESULTS
  The OMP group had lower BVF and BMD levels compared to the other groups at day 7 (P <0.05). Maximum messenger ribonucleic acid expression of both cytokines was observed in the OMP group at day 1 (P <0.05). In the same period, all proteins were expressed in high levels for all test groups compared to the control group. The number of cells positive for IL-1β and TNF-α by IHC was highest in the OMP group at day 1, with progressive reduction thereafter.
  
  
  CONCLUSIONS
  The results suggest that OM acts synergistically with periodontal disease in periodontal breakdown through upregulation of proinflammatory cytokines.
authors.affiliation: Department of Diagnosis and Surgery, School of Dentistry at Araraquara, Univ Estadual Paulista-UNESP, Araraquara, Brazil.
authors.forename: Andressa Vilas
authors.initials: AV
authors.lastname: Boas Nogueira
authors.forename: João Antonio
authors.initials: JA
authors.lastname: Chaves de Souza
authors.forename: Yeon Jung
authors.initials: YJ
authors.lastname: Kim
authors.forename: Manoel
authors.initials: M
authors.lastname: Damião de Sousa-Neto
authors.forename: Carolina
authors.initials: C
authors.lastname: Chan Cirelli
authors.forename: Joni Augusto
authors.initials: JA
authors.lastname: Cirelli
mesh_terms: D016301:Alveolar Bone Loss / Q000209:etiology* / Q000276:immunology; D000539:Alveolar Process / Q000276:immunology / Q000473:pathology; D000818:Animals; D015519:Bone Density / Q000502:physiology; D005881:Gingiva / Q000276:immunology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D018836:Inflammation Mediators / Q000032:analysis; D053583:Interleukin-1beta / Q000032:analysis*; D008297:Male; D009969:Orthodontic Wires; D010518:Periodontitis / Q000150:complications*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D018836:Inflammation Mediators; D053583:Interleukin-1beta; D014409:Tumor Necrosis Factor-alpha