2009 Volume 72 Issue 1 Pages 18-33
The objective of this study was to clarify the effect of platelet-rich plasma (PRP) on alveolar bone around implant fixtures. Although various studies on PRP have been reported, it has not been clarified what growth factor contained in PRP promotes new bone formation around implants in the early bone formation process. Likewise, bone quality, new bone mass, and differences between the pre- and postoperative osteocalcification rates are not well understood. We investigated these issues using immunohistochemical staining and histological examination. We experimentally prepared alveolar bone defects in six adult female beagles, similar to defects created by implant placement, and placed fixtures in the defects. The implant regions were divided into those treated with blood clot, those treated with transplanted autologous bone alone, those treated with PRP alone, and those treated with PRP plus autologous bone. The concomitant application of PRP to bone-defective regions around implant fixtures generated the following results. Histologically, immature new blood vessels and new bone were formed in the PRP plus autologous bone graft group. Immunohistochemical examination of growth factors released in the early process of healing revealed that the transforming growth factor-β and basic fibroblast growth factor levels were high. Vascular endothelial growth factor -positivity was noted in the early phase in the PRP plus autologous bone graft group. The osseous tissue form measurement method clarified the bone quality, new bone mass, and pre- and postoperative osteocalcification rates. All of these were greater in the PRP plus autologous bone graft group than in the other groups. New bone forming capacity was greater in the autologous bone graft than in the PRP graft group. We also found that Villanueva bone staining may be useful for the observation of new bone. These findings suggest that the concomitant application of PRP and autologous bone in the bone-defect regions around implants promotes the growth of blood vessels necessary for wound healing of the tissue, and is effective for long-term bone regeneration.
