title: Correlation of platelet growth factor release in jawbone defect repair--a study in the dog mandible.
abstract: BACKGROUND
  Platelet concentrate/platelet-rich plasma (PRP) has been studied extensively in various experimental models and there is some agreement among workers to its early effect in bone regeneration and healing. We have earlier showed in vitro that titanium in whole blood activates the thrombogenic response to a higher degree than PRP and that a fluoridated test surface augmented the effect compared with control.
  
  
  OBJECTIVE
  We designed this study to evaluate the effect of PRP and whole blood on bone regeneration in a dog implant defect model and, in addition, the effect of a test surface modified in hydrofluoric acid. A correlation attempt between platelet count, release of growth factors, and bone regeneration was made.
  
  
  METHODS
  Six dogs were used and simultaneously with the experimental surgery and implant installation, autologous PRP was prepared. Defects were prepared (6 mm in diameter and 5 mm deep), and implants were installed (TiO2 gritblasted and hydrofluoric acid treated [test] or TiO2 gritblasted [control], 5 mm in diameter and 9 mm long) in defects filled with either PRP or whole blood. Randomization of sides between PRP and whole blood, and sites for test and control implants were made. Blood samples were collected from PRP and whole blood. The dogs were killed after 5 weeks of healing, and samples with implants and surrounding bone were collected and processed for analysis. Enzyme linked immunosorbent assays were used for detection of growth factors in PRP.
  
  
  RESULTS
  The mean increase of platelet count was 424% in PRP. A correlation for platelet counts and transforming growth factor β was found in each dog (r(2) = 0.857). Approximately 50% of the region of interest (ROI) in the defects was filled with new bone after 5 weeks. No difference could be observed in ROI by using PRP or whole blood in the defects regarding new bone formation, bone in contact with implant, or distance to first bone contact. However, the fluoridated implants exhibited more new bone formation (p = .03) compared with control, regardless of comparing PRP or whole blood, and also displayed a shorter distance from first bone contact to the margin of the bone envelope (p = .05).
  
  
  CONCLUSIONS
  Platelet concentrate/PRP failed to show more new bone regeneration in a peri-implant defect model compared with whole blood. Implants treated with hydrofluoric acid displayed higher percentages of bone fill in the defect.
authors.affiliation: Department of Surgical Sciences, Oral & Maxillofacial Surgery, Uppsala University, Uppsala, Sweden Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden Department of Oral & Maxillofacial Surgery, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Göteborg, Sweden Department of Oral & Maxillofacial Surgery, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Göteborg, Sweden Department of Oral & Maxillofacial Surgery, Institute of Odontology, The Sahlgrenska Academy, University of Göteborg, Göteborg, Sweden.
authors.forename: Andreas Li
authors.initials: AL
authors.lastname: Thor
authors.forename: Jaan
authors.initials: J
authors.lastname: Hong
authors.forename: Göran
authors.initials: G
authors.lastname: Kjeller
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
authors.forename: Lars
authors.initials: L
authors.lastname: Rasmusson
mesh_terms: D000818:Animals; D004285:Dogs; D005260:Female; D008334:Mandible / Q000378:metabolism / Q000473:pathology*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*
chemical_list: D010982:Platelet-Derived Growth Factor