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Growth Factor Enhancement to Improve Implant Outcomes
Advantages of using PRP and PRF therapies for implant patients
Jamie Oshidar, DMD
Roselle Park, New Jersey
To achieve successful dental implant placement, one of the essential conditions is the presence of sufficient residual bone at the site. Much research has been done to improve the efficiency of bone grafting. As explained and demonstrated in the case presentation, one method of ameliorating bone-graft healing involves the use of growth factor enhancement.
Growth factors are bioactive proteins that have a role in controlling biological processes, such as cell growth, proliferation, and differentiation; they also can facilitate hard- and soft-tissue repair and regeneration.1 After binding to specific cell surface receptors, growth factors can then target cells in a number of recognized ways or modes and orchestrate the complex sequence of cell migration, division, differentiation, and protein expression during wound healing.
There are eight major classes of growth factors2 that are expressed in varying levels by the cells involved with healing; the effects of each growth factor are regulated through a complex system of feedback loops. Advances in the areas of cellular and molecular biology have allowed for better understanding of the functions that growth factors play in the various phases of wound healing. In vitro and in vivo studies have confirmed their ability to enhance the capacity of tissues to regenerate by regulating cell chemo-attraction, differentiation, and proliferation. Studies have also examined their use for alveolar bone regeneration in periodontal, reconstructive, and pre-prosthetic surgery, including rehabilitation with dental implants.
Platelets isolated from the peripheral blood are an autologous source of growth factors. In 1974, Ross et al published one of the first papers describing the regenerative potential of platelets.3 In the general medical setting, platelets are used to prevent and treat a variety of bleeding conditions, including severe thrombocytopenia, severe oral hemorrhage, and acute leukemia. The use of fibrin glue or adhesives, which consist primarily of fibrinogen and thrombin, helped to initiate the development of platelet concentrate as a bioactive surgical additive.3 In addition, a number of blood components have been increasingly recognized as being part of the natural healing process, with the potential to accelerate wound healing when added to injured tissues or surgical sites.3
Reparation and regeneration of the soft and hard tissues after periodontal surgical procedures can be improved with the use of platelet concentrates. Growth factors are released after activation from platelets trapped within fibrin matrix, which in turn stimulates the mitogenic response in the periosteum for bone repair during normal wound healing. The growth factors listed below can be found in the environment of a blood clot:1,4
• Transforming growth factor beta (TGF-b)
• TPlatelet-derived growth factor (PDGF)
• Insulin-like growth factor (IGF)
• Vascular endothelial growth factors (VEGF)
• Epidermal growth factor (EGF)
• Fibroblast growth factor-2 (FGF-2)
Platelet-derived growth factor (PDGF), which is synthesized by platelets, monocytes, macrophages, endothelial cells, and osteoblasts, has been extensively investigated for clinical applications and appears to have broad wound-healing activities in both hard and soft tissue.4 A naturally occurring protein, it is abundant in bone matrix and is released locally by blood platelets during clotting following a soft- or hard-tissue injury. After its release from the platelets, PDGF binds to specific cell surface receptors and promotes rapid cell migration and proliferation in the injured area. Both in vitro and in vivo studies suggest that PDGF is a potent chemotactic and mitogenic factor for gingival and periodontal ligament fibroblasts, cementoblasts, and osteoblasts.
The initial idea was to concentrate platelets and their growth factors and to deliver the preparation to a surgical site in order to improve and expedite healing. Studies have demonstrated promising effects in that the use of these autologous products results in better and more rapid healing, and regeneration of both soft and hard tissue.5 Because healing is more rapid, the risk of complications such as infection, dry socket, failed implants, or failed grafting is lower. These procedures may be particularly useful for individuals who are at risk for impaired healing such as diabetics, smokers, and/or those with chronic or acute conditions that can interfere with healing.
Various methods of using autologous platelet concentrates have been developed and are being used in oral and maxillofacial surgery. The “first generation” incorporates the platelet-rich plasma (PRP), and is the precursor of another autologous derivate, the platelet-rich fibrin (PRF), which is a solid fibrin-based biomaterial.