A Randomised Control Clinical Trial Investigating the Effect of L-PRF on Implant Stability and Marginal Bone Levels.

Osseointegration refers to the formation of a structure and functional bone-to-bone interface, without the interposition of soft tissue. Successful osseointegration is imperative to implant success and relies on a number of factors including implant design, material, surface and finish the bone status, surgical technique and implant loading conditions. Primary implant stability is the bio-mechanical stability achieved for implants at the time of placement and is achieved through micromovements of the implant. Following healing of the osteotomy site and formation of new bone a biological fixation of the implant to bone results and is referred to as secondary implant stability. Such as with osseointegration, there are several factors that affect primary implant stability including insertion torque, implant design, density of bone and surgical technique. To achieve future implant osseointegration, primary stability must first be accomplished.

Leukocyte and platelet rich fibrin (L-PRF) is formed by centrifuging venous blood using an IntraSpin® machine (U.S Food and Drug Administration approved and CE marked for in-vivo use) at 2700 revolutions per minute for 12 minutes. Following removal from the L-PRF tubes the fibrin clot is separated from the red blood cell clot. The fibrin clot is then transferred to the PRF box and the Xpression™ tray is placed over the fibrin clot and after 5 minutes the L-PRF membrane is ready for use.

During the traditional implant placement there is an osteotomy cut in practical terms is a controlled fracture of the bone resulting in rupture of local blood vessels which almost immediately sparks a cascade of healing including hemostasis, inflammation and proliferation of cells and tissue maturation. Our study will include Leukocyte platelet rich fibrin surrounding the implant at the osteotomy site which is a robust fibrin mesh which provides a progressive release of growth factors improving angiogenesis, osteoblastic proliferation, and cell differentiation. L-PRF utilization during implant placement attempts to expedite the process by delivering growth factors to the surface of the implant and surrounding bone promoting the healing process. Experimental research has shown that delivery of molecules or growth factors to an implants surface may increase osteoblast activity and improve functional integration of the implant.

Pre-clinical tests have shown that the utilization of platelet growth factors improve wound healing, proliferation of cells and implant osseointegration in animal models. Further pre-clinical studies have shown that L-PRF increased the rate and amount of new bone formation in rabbits.

Limited human tests in small populations not including the mandible have shown positive outcomes with improvement in implant stability when L-PRF was utilized during implant placement. High quality clinical evidence on this topic is limited and must be improved to allow clinicians to make evidence-based decisions on L-PRF utilization.

The proposed study will be a randomized control trial comparing the use of L-PRF in implant placement versus conventional implant placement. Considering the extra step of phlebotomy and time for centrifuging of the blood samples the literature must show a clinical benefit if this technique is to be utilized into the future. This study aims to add to available clinical evidence and address some of the limitations in current evidence to aid clinicians to make evidence-based decisions on whether to utilize LPRF to improve implant stability and hence earlier loading of implants.