title: Mechanism of action and morphologic changes in the alveolar bone in response to selective alveolar decortication-facilitated tooth movement.
abstract: OBJECTIVE
  The aim of this study was to test if corticotomy-induced osteoclastogenesis and bone remodeling underlie orthodontic tooth movement and how selective alveolar decortication enhances the rate of tooth movement.
  
  
  METHODS
  A total of 114 Sprague-Dawley rats were included in 3 treatment groups: selective alveolar decortication alone (SADc); tooth movement alone (TM); and "combined" therapy (SADc + TM). Surgery was performed around the buccal and palatal aspects of the left maxillary first molar tooth and included 5 decortication dots on each side. Tooth movement was performed on the first molar using a 25-g Sentalloy spring. Measurements were done at baseline (day 0: no treatment rendered) and on days 3, 7, 14, 21, 28 and 42. Microcomputed tomography, Faxitron analyses, and quantitative real-time polymerase chain reaction (q-PCR) of expressed mRNAs were used to assess changes.
  
  
  RESULTS
  The combined group showed increased tooth movement (P = 0.04) at 7 days compared with the tooth movement group with significantly decreased bone volume (62%; P = 0.016) and bone mineral content (63%; P = 0.015). RNA markers of osteoclastic cells and key osteoclastic regulators (M-CSF [macrophage colony-stimulating factor], RANKL [receptor activator of nuclear factor kappa-B ligand], OPG [osteoprotegerin], calcitonin receptor [CTR], TRACP-5b [tartrate-resistant acid phosphatase 5b], cathepsin K [Ctsk]) all showed expression indicating increased osteoclastogenesis in the combined group. RNA markers of osteoblastic cells (OPN [osteopontin], BSP [bone sialoprotein], OCN [osteocalcin]) also showed increased anabolic activity in response to the combination of alveolar decortication and tooth movement.
  
  
  CONCLUSIONS
  The data suggest that the alveolar decortication enhances the rate of tooth movement during the initial tooth displacement phase; this results in a coupled mechanism of bone resorption and bone formation during the earlier stages of treatment, and this mechanism underlies the rapid orthodontic tooth movement.
authors: Department of Orthodontics and Dentofacial Orthopedics, Boston University Goldman School of Dental Medicine, Boston, MA, USA.
authors: S Susan
authors: SS
authors: Baloul
authors: Louis C
authors: LC
authors: Gerstenfeld
authors: Elise F
authors: EF
authors: Morgan
authors: Roberto S
authors: RS
authors: Carvalho
authors: Thomas E
authors: TE
authors: Van Dyke
authors: Alpdogan
authors: A
authors: Kantarci
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D000818:Animals; D015519:Bone Density; D016723:Bone Remodeling / Q000235:genetics; D056657:Cathepsin K / Q000096:biosynthesis; D003799:Dental Stress Analysis / Q000379:methods*; D058574:Integrin-Binding Sialoprotein / Q000096:biosynthesis; D016173:Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D008437:Maxilla; D010006:Osteoblasts / Q000378:metabolism; D015675:Osteocalcin / Q000096:biosynthesis; D010010:Osteoclasts / Q000378:metabolism; D053495:Osteopontin / Q000096:biosynthesis; D053244:Osteoprotegerin / Q000096:biosynthesis; D010513:Periodontal Ligament / Q000502:physiology; D016133:Polymerase Chain Reaction; D053245:RANK Ligand / Q000096:biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D018003:Receptors, Calcitonin / Q000096:biosynthesis; D014087:Tooth Movement Techniques / Q000379:methods*; D055114:X-Ray Microtomography
chemical_list: D058574:Integrin-Binding Sialoprotein; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D018003:Receptors, Calcitonin; D015675:Osteocalcin; D053495:Osteopontin; D016173:Macrophage Colony-Stimulating Factor; D056657:Cathepsin K