Clinical Applications Of Platelet-rich Fibrin (PRF) In Alveolar Bone Defect For Implantation And Restoration

Purpose: This study aims to observe the clinical efficacy of PRF in the restoration of bone defects around dental implants.The method of platelet concentration of PRF(Platelet-Rich Fibrin)was established by Choukroun,a French doctor,in 2001.Through this method,PRF could be extracted from the body's blood without any special treatment.PRF was proved to promote the growth and proliferation of osteoblasts.Previous studies showed that PRF could be used as bone graft material.As the ridge preservation after tooth extraction,directly filling PRF in the alveolar bone could reduce bone resorption after tooth extraction;As bone splitting surgery,we mixed PRF fibrin clot,bone powder,and other substances to fill in bone defects.On the one side,it facilitated the filling of bone powder,not easy to loose or displace.On the other side,it induced the growth of osteoclast and regeneration of soft tissue.As doing sinus lifting surgery,PRF could be placed on the bottom of the maxillary sinus to prevent the rupture of mucous membrane of maxillary sinus as lifting.In the process of implant surgery,we also could press the middle of the light yellow fibrin clot in PRF into a film as regeneration membrane or directly covered in the wound.The autologous platelet concentrated products contain various growth factors,cytokines,and active proteins required for normal wound healing and promote vascular regeneration,wound healing,and attachment and regeneration of defected bones.Method: A total of 10 dental implant patients,from January 2013 to January 2017,were selected in the study.Among them were 6 males and 4 females,and the age range was from 35 to 65.A total of 16 implants were placed.All the patients used PRF in the course of treatment.Among these 10 patients,there are 4 cases of simple ridgepreservation,2 cases of ridge preservation and the maxillary sinus lifting,2 cases of bone splitting,and 2 cases of immediate implant.PRF productive process:We collected venous blood from the patients and stored in silica-free tubes.Based on the sizes,parts,and methods of the patients' implant wounds,we determined the volumes of blood we drew.The volumes of blood in each test tube was 10 ml.In general,the blood we drew was from 10 to 60 ml.After blood extraction,it must be immediately placed in a centrifuge for centrifugation.The speed / time of the centrifuge is 3200 rpm / 12 min.After centrifugation,the products centrifuged out of each tube can be divided into three layers.The first layer(upper layer)is PPP(platelet-poor plasma).The second layer(intermediate layer)is fibrin clot.The third layer(bottom layer)is red corpuscules base.In general operative procedure,after mixing the upper layer of PPP(Platelet poor plasma)with bone powder,we directly filled them in bone defects,in order to induce osteocyte regeneration and enhance bone graft effect.We pressed the middle layer of fibrin clot into a regenerative membrane,covered in the wound,to do the suture.It could help the regeneration and healing of soft tissue.As doing sinus lifting surgery,fibrin clot could be placed on the bottom of the maxillary sinus to prevent the rupture of mucous membrane of maxillary sinus as lifting.Results: These 10 patients didn't have postoperative infection,and their wounds were healed by first intention.The patients didn't obviously have the feeling of pain and swelling.After PRF implantation,the bone mass of all the patients increased in different degrees.All of the implants completed the final restoration.After the follow-up observation of 1 year to 1 and a half years,all of the 16 implants were not loosened and fallen off.The success rate was 100%.The patients were satisfied with the course of treatment and healing effects.Conclusion: PRF is applicable to a variety of restoration of alveolar bone defects,including ridge preservation,maxillary sinus lifting,bone splitting,and so on.PRF not only can be used as repairing materials of bone defects,and also can be used asrepairing materials of soft tissue defects.PRF can reduce postoperative reaction and promote wound healing.