title: Bone remodeling at microscrew interface near extraction site in the beagle dog mandible-histologic and immunohistochemical analyses.
abstract: Extraction is often used as part of orthodontic therapy, and good control of anchorage is a key step after extraction. Although microscrews can be implanted close to the extraction site in order to achieve orthodontic support, the efficiency of bone remodeling at the implant-bone interface near the extraction region is dubious.
  
  
  OBJECTIVE
  The purpose of this study was to investigate bone remodeling of the bone-microscrew interface near the tooth extraction site, in the absence of loading.
  
  
  METHODS
  Third and fourth premolars were extracted from the mandibles of beagle dogs, followed by placement of test microscrews near the extraction sites. Control microscrews were placed further away from the extraction site. All samples were collected after 1, 3, 8, or 12 weeks of healing following extraction. The bone remodeling process at the interface was evaluated using histologic and immunohistochemical analyses.
  
  
  RESULTS
  Initially, a large number of inflammatory cells were aggregated at the interface. The expression levels of core binding factor (Cbfa1), osteocalcin (OC) and transforming growth factor beta (TGF-β) were inconspicuous in both groups, whereas tumor necrosis factor alpha (TNF-α) was strongly expressed, especially in the test groups (P<0.05). Subsequently, the expression levels of Cbfa1, OC and TGF-β were found to increase significantly, and active osteogenesis was observed.
  
  
  CONCLUSIONS
  During week 1, inflammatory reaction is a major concern at the bone-microscrew interface near the extraction site. However, with healing, the influence of extraction on the remodeling of bone surrounding the microscrews decreases, thus facilitating successful treatment.
authors.affiliation: Department of Orthodontics, Affiliated Hospital of Stomatology, Chongqing Medical University, Chongqing, P. R. China.
authors.forename: Guangxi
authors.initials: G
authors.lastname: Wei
authors.forename: Yun
authors.initials: Y
authors.lastname: Hu
authors.forename: Leilei
authors.initials: L
authors.lastname: Zheng
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Huo
authors.forename: Tian
authors.initials: T
authors.lastname: Tang
authors.forename: Feng
authors.initials: F
authors.lastname: Deng
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000502:physiology*; D001863:Bone Screws; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D004285:Dogs; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000601:surgery; D013997:Time Factors; D014081:Tooth Extraction; D014945:Wound Healing / Q000502:physiology
chemical_list: D015921:Dental Implants