OBJECTIVE To investigate the clinical effect of platelet-rich fibrin (PRF) combined with guided bone regeneration (GBR) in the reconstruction of peri-implantitis bone defect. METHODS This prospective study included 80 patients with peri-implantitis who underwent implant restoration in the Department of Stomatology in our hospital. The eligible patients were randomly divided into control group and observation group, with 40 cases in
each group. Patients in the control group were treated with flap curettage combined with GBR, while those in the observation group received a mixture of PRF and bone powder implanted with GBR and covered with PRF biofilm. The differences of pain 24 hours after surgery, bleeding at 7 days after surgery, and the degree of bone defect between the two groups at 60 days after surgery were compared. At 60 days and 120 days after surgery, separately, the regenerated bone density of patients in the two groups was measured, analyzed and compared. The degree of regenerated bone defect in transverse and longitudinal directions after 60 days was compared between the two reconstruction procedures. RESULTS The pain at 24 hours after surgery and the bleeding at 7 days after surgery in the observation group were milder than those in the control group (P<0.001). There was significant difference in the degrees of bone defect at 60 days after surgery (P<0.05). Compared with the control group, the regenerated bone density of the observation group was significantly higher both at 60 days and 120 days after surgery (P<0.001). CONCLUSION The combination of PRF and GBR technology has an obvious effect in repairing bone defects in patients with peri-implantitis, and can reduce the pain of patients during the repair process.