Abstract: Objective To investigate the effect of autologous tooth-bone graft combined with platelet-rich fibrin on peri-implant defects and the underlying mechanism. Methods A total of 40 New Zealand white rabbits were randomly divided into the experimental groups A, B, C and the blank control group. Under the condition of general anesthesia, a minimally invasive surgical procedure was performed to extract the animals’maxillary anterior teeth. The tooth socket of rabbits in the experimental group A were implanted with autologous tooth-bone grafts combined with platelet-rich fibrin. That in experimental group B was only implanted with autogenous tooth-bone grafts. Rabbits in experimental group C experienced only the implantation with platelet-rich fibrin, and no material was implanted in blank control group. The activity of alkaline phosphatase (ALP), the gray values of typeⅠcollagen, osteoprotegerin (OPG) and its ligand (RANKL), the mRNA expression levels of Runx2, ALP and platelet reactive protein-1 were compared and analyzed. Results The ALP activity, the gray values of typeⅠcollagen and OPG, the mRNA expression levels of Runx2, ALP and platelet reactive protein-1 in the experimental groups were higher than those in the blank control group. The values of the above indexes in the experimental group A were significantly higher than those in experimental groups B and C ( P < 0. 05). Although the gray values of RANKL in each group were significantly increased with time (P< 0. 05), there was no significant difference in the gray values of RANKL between the experimental groups and the blank control group at each time point (P > 0. 05). Conclusion The combination of platelet-rich fibrin enhanced the repair of peri-implant defects in the process of autologous tooth-bone transplantation.

Key words: autogenous tooth-bone graft, platelet-rich fibrin, platelet reactive protein-1, peri-implant defects