title: Histologic investigation of gingival epithelium implantation and the nonincision placement of miniscrews.
abstract: OBJECTIVE
  This study investigated whether the nonincision placement of miniscrews could lead to ectopic implantation of epithelium at the bone-implant interface and, if so, whether the epithelial cells could survive. The fate of grafted epithelial cells was also investigated.
  
  
  METHODS
  Ten healthy male beagle dogs were included in the study and were divided into three groups. Group 1 dogs (n = 3) were implanted with miniscrews without any other procedures. In group 2, epithelial cells were collected, infected by adeno-associated virus-2 containing green fluorescent protein (GFP), and injected into pilot holes drilled before miniscrew implantation in three dogs, and one dog was injected with epithelial cells as a negative control. In group 3, tiny gingival tissue pieces were injected into pilot holes drilled before miniscrew implantation. In group 1, hematoxylin-eosin and fluorescent immunohistochemical (IHC) staining of cytokeratin were performed on both undecalcified and decalcified slices. In groups 2 and 3, IHC staining of cytokeratin and apoptotic testing were performed.
  
  
  RESULTS
  No ectopically implanted epithelial cells were found at the bone-implant interface of the miniscrews in group 1. In group 2, fluorescence emitted by cytokeratin antibody and by GFP was observed in specimens at 0 days, had decreased by 3 days, and had disappeared by 7 days. In group 3, areas of fluorescent cytokeratin-positive tissues were much smaller at 7 days than at 0 days, and none were found at 28 days. In groups 2 and 3, there were many apoptotic epithelial cells at the bone-implant interface at 3 days and 7 days, respectively.
  
  
  CONCLUSIONS
  There was little possibility of implantation of epithelium into alveolar bone though placement of miniscrews with a nonincision procedure. Furthermore, even when epithelial cells or tissue was ectopically implanted, it was soon cleared through an apoptotic process.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jieli
authors.initials: J
authors.lastname: Ni
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Smales
authors.forename: Junqing
authors.initials: J
authors.lastname: Ma
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
mesh_terms: D000539:Alveolar Process / Q000166:cytology; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001863:Bone Screws; D002452:Cell Count; D018929:Cell Culture Techniques; D000229:Dependovirus / Q000235:genetics; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology; D005881:Gingiva / Q000166:cytology*; D049452:Green Fluorescent Proteins; D015603:Keratinocytes / Q000166:cytology; D007633:Keratins / Q000032:analysis; D008297:Male; D008334:Mandible / Q000166:cytology / Q000601:surgery*; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties; D014162:Transfection
chemical_list: D049452:Green Fluorescent Proteins; D007633:Keratins