Evaluation of the effects of platelet rich fibrin on bone healing in surgically created defects around implants

The use of a dental implant has become a common treatment and an important part of modern dentistry. Immediate implant placement into fresh extraction sockets has been recommended as a means to minimize bone loss and shorten the prosthetic treatment time. Surgically created bone defects around dental implants simulate fresh extraction sockets in experimental animal models. However, the residual bone defects, between the implant neck and the residual bone walls, may cause cell migration from the connective and epithelial tissue into the defect area, possibly preventing osseointegration and jeopardize the success of immediate implant procedures. For such defects, bone augmentation procedures in combination with the implant placement are necessary. Additional procedures can be used to shorten the bone healing period in bone augmentation and to strengthen the implant bone connection. The success of various surgical technics, biomaterials and anabolic agents has been evaluated in treatment of such defects. The use of platelet rich fibrin (PRF) which is a platelet concentrate is recently popular in bone regeneration. However, there is a limited data in the literature about the effectiveness of PRF in periimplant defects. The aim of this experimental study is to evaluate the contribution of PRF and bovine-derived hydroxyapatite (HA) graft to bone healing in surgically created bone defects around dental implants. In this experimental study, 5 adult male sheep were used. Eight Standard bone defects 10 mm in diameter and 4 mm in depth were created in pelvis of the sheep. Fourty dental implants were placed at the center of the surgically created uniform defects. In each animal, two defects were filled only with PRF, two defects were filled per defect only 0,3 cc bovine derived HA bone graft, two defects were filled with equal volume of PRF and bovine derived HA bone graft mixture and two defect were left empty as a control group. All defects were covered with collagen membranes. All animals were sacrified after 8 weeks of healing period. The implants with surrounding bone defects were removed en bloc. Undecalcified sections were prepared for histomorphometric analysis. The data were analyzed statistically. In conclusion, the use of PRF alone or with bovine derived HA bone graft in surgically created periimplant defects did not show an additional contribution to bone regeneration and osseointegration. Key Words: Implant, periimplant bone defect, PRF, platelet concentrates, bone regeneration, osseointegration, histomorphometry