Growth Factors in Dentistry and how we use them in our clinic

In 1986  Rita Levi Mondelcini and her colleague Stanley Cohen received the Nobel Price in Medicine for their discovery in Growth Factors. Since then a lot of research has led to understanding of the importance of Growth Factors in the human body and healing. Platelets’ regenerative potential was introduced when it was observed that they contain growth factors that are responsible for increase collagen production, cell mitosis, blood vessels growth, recruitment of other cells that migrate to the site of injury, and cell differentiation induction, among others.

Platelet Rich Plasma or PRP therapy has made headlines in our days because it is widely used in medicine.

• Doctors first used PRP to help people heal after jaw and plastic surgeries.
• It is favoured by elite athletes to help them recover from injuries (tendons ligaments and muscles).
• PRF (platelet rich fibrin membranes) also helps healing of diabetic foot ulcer
• PRP treatments can enhance hair restoration and other cosmetic plastic surgery procedures

One of the latest innovations is in oral surgery where they use platelet concentrates for in vivo tissue engineering applications: 1) platelet-rich plasma (PRP) and 2) platelet-rich fibrin (PRF). Platelet concentrates are a concentrated suspension of growth factors found in platelets, which act as bioactive surgical additives that are applied locally to induce wound healing.

Whitman et al , in 1997, were the first to introduce the use of platelet-rich plasma in oral surgical procedures, reporting great advantages because it enhances osteoprogenitor cells in the host bone and bone graft .On the other hand, PRF was first used in 2001 by Choukroun et al. , specifically in oral and maxillofacial surgery, and is currently considered as a new generation of platelet concentrate.

It consists of a matrix of autologous fibrin and has several advantages over PRP, including easier preparation and not requiring chemical manipulation of the blood, which makes it strictly an autologous preparation.

PRF membrane helps in wound healing, protecting the surgical site, promoting soft tissue repair .When mixed with bone graft, it may act as a “biological connector”, which attracts stem cell, favors the migration of osteoprogenitor cells to the centre of the graft, and provides a neo-angiogenesis.

Protocol for PRF preparation that we use in our clinic

The protocol tries to accumulate platelets and the released cytokines in a fibrin clot. Platelets are the second-most numerous corpuscles in the blood. Their lifetime is between 7 and 10 days.

1. PRF protocol requires only centrifuged blood. A blood sample is taken without anticoagulant in 10-mL glass tubes and immediately centrifuged.

The resultant product consists of the following three layers:

• Top-most layer consisting of a cellular plasma.
• PRF clot in the middle.
• Red corpuscle base at the bottom.

2. After this, it is necessary to put the PRF clot in a sterile cup for approximately 10 minutes to allow the release of the proper serum contained within. Mazor et al. reported that clot could be transformed into a membrane through the compression between two sterile gauzes or in a specific tool.

Advantages of using PRF

Some advantages are reported in the literature related to the use of PRF, such as the following:

1. Its preparation is a simplified and efficient technique, with centrifugation in a single step, free and openly accessible for all clinicians.
2. It is obtained by autologous blood sample.
3. Minimized blood manipulation.
4. It does not require the addition of external thrombin because polymerization is a completely natural process, without any risk of suffering from an immunological reaction.
5. It has a natural fibrin framework with growth factors within that may keep their activity for a relatively longer period and stimulate tissue regeneration effectively.
6. It can be used solely or in combination with bone grafts, depending on the purpose.
7. Increases the healing rate of the grafted bone.
8. It is an economical and quick option compared with recombinant growth factors when used in conjunction with bone grafts.
9. Used as a membrane, it avoids a donor site surgical procedure and results in a reduction in patient discomfort during the early wound-healing period.
10. The studies of PRF present it to be more efficient and with less controversies on its final clinical results when compared to PRP.

Disadvantages of using PRF

PRF may present some disadvantages as follows:

1. The final amount available is low because it is autologous blood.
2. The success of the PRF protocol depends directly on the handling, mainly, related to blood collection time and its transference for the centrifuge.
3. Need of using a glass-coated tube to achieve clot polymerization.
4. Possible refusal of treatment by the puncture required for blood collection (Wani 2014).
5. Only needs a minimal experience of clinician for PRF manipulation.

In conclusion In vitro and in vivo studies have demonstrated safe and promising results, without contradictory findings, related to the use of PRF alone or in combination with other biomaterials. It has several advantages and possible indications to be used both in medicine and dentistry. Currently, platelet-rich fibrin seems to be an accepted minimally invasive technique with low risks and satisfactory clinical results.