title: RANKL and OPG expression: Jiggling force affects root resorption in rats.
abstract: OBJECTIVE
  To immunohistochemically investigate the longitudinal changes in root resorption by jiggling force in experimental animal models.
  
  
  METHODS
  Fifty-six 12-week-old male Wistar rats were used. The maxillary first molars were alternately moved in the buccal and lingual direction in 28 rats (experimental group) using an experimental appliance to produce jiggling forces of 10 g. In another 28 rats (control group), the maxillary first molars were moved in only the lingual direction with a force of 10 g. After 1, 3, 7, 10, 14, 17, and 21 days, the maxillae were resected and subjected to immunohistochemical analysis. The resorption area was quantified histomorphometrically and the number of odontoclasts on the root surface was counted. Expression of RANKL and OPG was also examined by immunohistochemical staining.
  
  
  RESULTS
  The root resorption area and the number of odontoclasts were significantly greater in the experimental group than in controls. Odontoclasts were detected in the resorption lacunae and PDL in the experimental group, whereas osteoclasts were located only along the alveolar bone in controls. OPG was detected on the alveolar bone in the experimental group and on the root surfaces of the controls.
  
  
  CONCLUSIONS
  Jiggling force is a critical factor in severe root resorption, affecting RANKL and OPG expression, which accelerates and inhibits odontoclastic induction, respectively.
authors.forename: Yayoi
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Masahide
authors.initials: M
authors.lastname: Motokawa
authors.forename: Masato
authors.initials: M
authors.lastname: Kaku
authors.forename: Hiromi
authors.initials: H
authors.lastname: Sumi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanne
authors.forename: Kotaro
authors.initials: K
authors.lastname: Tanimoto
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D007150:Immunohistochemistry; D008297:Male; D008437:Maxilla; D023421:Models, Animal; D008963:Molar / Q000737:chemistry; D009969:Orthodontic Wires; D010010:Osteoclasts / Q000473:pathology; D053244:Osteoprotegerin / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012391:Root Resorption / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D013314:Stress, Mechanical; D013997:Time Factors; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000295:instrumentation; D014092:Tooth Root / Q000000981:diagnostic imaging / Q000473:pathology
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand; C506032:Tnfrsf11b protein, rat
keywords: Cytokines; Immunohistochemistry; Jiggling force; Odontoclast; Root resorption; Tooth movement