A dental implant is fast becoming the treatment of choice in replacing a missing tooth. However, the success of an implant is dependent, amongst others, on the availability of adequate alveolar bone to house the implant, something which is not always there. With such demand, the need for augmenting the bone has risen and along with that, the enhancement of the bone grafting. Platelet-rich plasma was one such technique introduced twenty years ago as a method to improve the healing of bone grafts.
The rationale for the use of platelet-rich plasma to enhance wound healing is that platelets are a rich source of growth factors. The technique involves drawing out some blood from the patient and centrifuging it so that the different components of blood are separated. The platelet portion is then extracted and mixed with the bone harvested from another site in the same patient. Bone grafts that are mixed with PRP are usually in particulate form and the PRP is in liquid form. After mixing them together, a clotting agent, usually thrombin derived from cows, is added to clump the whole mixture together into a soft putty that can be picked up and molded into shape.
However, there are many conflicting reports on the effectiveness of PRP in bone grafting. This may be attributed to the fact that the machines used to generate PRP were not standardized, which led to varying concentrations of platelets. Many used ordinary lab centrifuges to generate PRP instead of purpose-built machines, and the optimal concentration of platelets was no achieved. Another common misuse of PRP was mixing it with non-autogenous bone grafts. The growth factors in the platelets have to act on living cells to enhance their ability to attract local growth factors and cells to integrate with the graft. Non-autogenous bone grafts are inert bone substitutes derived from animal or cadaver bone minerals without any cells. As such, adding PRP to bone substitutes will not result in appreciable enhancement of bone graft consolidation.
In my practice, I use PRP extensively in my reconstructive surgeries. The major downside of PRP is the additional cost. Purpose-built machines require proprietary consumables which cost more than US$1000 per use. This adds to the already considerable cost of the overall treatment plan. As such, it is not used as often as I would like to.
More recently, a variant of PRP is gaining popularity. This is the commonly referred to as platelet-rich fibrin (PRF). This is a much more economical and user friendly method though the efficacy may not be the same. One of the major advantages is that no chemical additives are used in preparation of PRF. For PRP, an anticoagulant needs to be added to the blood collecting bags, calcium chloride and bovine thrombin need to be added to the final mixture with the bone graft. All these additives make the process more complicated and expensive. PRF does not require expensive proprietary machines and consumables. Nor does it require additives. Instead, it depends on the blood’s own clotting factors to coagulate. The yield of platelets is not quite as high but the ease of use and lower cost offer significant advantages.
In Singapore, the Ministry of Health regulates the use of PRP and PRF and limits their use to indications that have been validated by scientific research. Indications such as bone and gingival tissue surgery in relation to dental surgery as well as in orthopedic indications such as Achilles tendon surgery have been approved. However, the use of PRP injections in facial aesthetic procedures has not undergone the rigor of proper scientific validation and has not received approval from the regulators.