In recent years, platelet-rich fibrin (PRF) has emerged as a highly promising technique with many applications in dental surgery. The second generation of platelet concentrates – platelet-rich fibrin (PRF) – was subsequently introduced by Joseph Choukroun and his co-workers in 2001.
The biological properties of PRF clearly show an interesting surgical versatility and all the characteristics that can support faster tissue regeneration and high-quality clinical outcomes. PRF can stimulate osteogenesis as well as angiogenesis and it provides a scaffold thatallows cellular migration. These are certainly the fundamental aspects for bone regeneration.
Where and how can I use PRF?
A general rule of guidance is to use PRF in surgical situations where protection and stimulation of healing and regeneration is critical and where the prognosis for tissue repair is poor or potentially compromised.
PRF is indicated in numerous clinical applications, such as socket augmentation, jump gap filling during immediate extraction and implant placement, and stimulation of bone and soft tissue healing during bone augmentations or during sinus elevation.
PRF in implant dentistry
Increasing implant stability and osseo-integration
Case studies suggest that PRF application into the osteotomy site increases implant stability during the early healing period, as evidenced by higher ISQ values. Simple application of this material also provides faster osseointegration (Öncu and Alaaddinoõglu. 2015).Furthermore, when L-PRF is used during one-stage implant placement, the amount of initial bone remodelling (first three months after implant placement) can be reduced significantly.
The application of PRF in an extraction socket significantly reduces the horizontal/vertical ridge resorption, even at sites with bone dehiscence. The observed reduction in bone resorption is comparable to the current “best performing” clinical procedures (using a bone substitute in combination with connective-tissue graft or membrane).
As a filling material in extraction sockets, PRF will act as a stable blood clot for neovascularization and accelerated tissue regeneration. PRF as a filling material after third-molar extraction has a beneficial effect on both post-operative pain and soft-tissue healing. PRF enables fast neoangiogenesis and promotes bone regeneration via the release of growth factors and a good cloth stability.
Alveolar ridge preservation (socket augmentation) for early or late implant placement
Use of PRF membranes to fill the socket after tooth extraction has shown to improve alveolar bone healing and preservation of the alveolar crest width. PRF plugs or membranes can also be used to fill extraction sockets, even when associated with compromised extraction sockets (Peck, et al., 2011), severe cystic destructions, or after cyst enucleations (Choukroun, et al., 2006; Magremanne, et al., 2009) to allow early bone and gingival regeneration required for implant placement. Clinical and histological findings suggest that filling a fresh extraction socket with PRF provides a viable therapeutic alternative for implant site preparation (Zhao, et al., 2011).
Alternatively, PRF can also be mixed with a bone substitute to fill the socket and used as a protective cover over the grafted socket. This is particularly important when gingival wound closure is impossible or difficult with the sutures (Del Corso, et al., 2012).
The purpose of the PRF membrane is not only to stimulate gingival healing, but also to protect the bone graft from the oral environment and to maintain it within the extraction socket, like a biological barrier. It is suggested that this technique negates the need for using more complex flaps and GBR protocols to close and augment extraction sockets.
Sinus floor elevation – using PRF as sole or combination graft biomaterial
PRF can either be cut to fragments and mixed with different bone substitutes or can be used as a sole filling material during sinus floor elevation. PRF can be applied either via a lateral window technique or through a trans-alveolar approach. Several studies have confirmed a natural bone regeneration around the implants (± 10mm vertical bone gain with the window technique, ±4mm for trans- alveolar approach).
In Mazor and Simonpieri studies, one or two PRF membranes were placed on the sinus membrane and osteotomy window as a sole filling material and no grafting material was used to fill the created space. Implants were placed spontaneously with sinus lift and serve as tent pegs. Tent pegs technique based on guided bone regeneration as implants are placed immediately with sinus lift
A systematic review showed that PRF used as a sole filling material in SFE with simultaneous implant placement is a simple technique with promising results, Various clinical case reports describe the lateral approach for sinus floor elevation using only PRF as the grafting material (Mazor, et al., 2009; Simonpieri, et al., 2011; Tajim, et al., 2013).
Various case studies have demonstrated that PRF membranes can be used successfully as a protective barrier to cover the sinus membrane during grafting procedures (Diss, et al., 2008; Toffler, et al., 2010; Kanayama, et al., 2014). PRF membranes also represent an easy and successful method to cover sinus membrane or osteotomy window to protect the Schneiderian membrane, to facilitate wound closure, and to enhance healing (Ghetiu, et al., 2015). Cases have also been reported showing that A-PRF membrane can be used as a healing barrier when perforations or tears of the Schneiderian membrane occur (Diss, et al., 2008; Toffler, et al., 2010).
PRF combined with a bone allograft or other bone substitutes accelerates graft maturation and decreases the healing period before implant placement. The latter finding has also been confirmed by other clinical trials and case studies (Choukroun, et al., 2006; Tatullo, et al., 2012; Zhang, et al., 2012; Bölükbas, et al., 2013).
Guided bone regeneration
As a membrane for guided bone regeneration (GBR), the PRF dense matrix architecture covers, protects and stabilizes bone graft material.
PRF liquid (i-PRF) can be injected above, or PRF (A-PRF or L-PRF) membrane placed above the GBR or GTR membrane to act as an interposition barrier to protect and stimulate the bone compartment, and as a healing membrane in order to improve the soft tissue healing and remodeling, and thus avoid soft tissue dehiscence (Peck, et al., 2011; Inchingolo, et al., 2010).
The bone/PRF mixture in the augmented site is covered with a cross-linked collagen membrane to maintain the bone compartment and to prevent ingrowth of soft tissue. The collagen membrane is overlaid with a double layer of PRF membranes. These membranes are used as a competitive interposition barrier to protect and stimulate the bone compartment, and as healing membranes to stimulate the periosteum and gingival healing and remodeling. Periosteal releasing incisions are done on the flaps to promote their tension-free closure.
Immediate post-extraction implant placement and jump-gap augmentation — peri-implant healing
PRF is considered as a healing biomaterial with beneficial effect on peri-implant tissue and can be used as a therapeutic adjuvant with immediate implant placement in the clinical scenario of one-stage, single-tooth implant placement procedure in maxillary anterior region (Del Corso, et al., 2012).
With immediate implant placement, the peri-implant jump gap can be augmented with PRF clot (A-PRF or L-PRF) or solution (i-PRF) mixed with a bone substitute (Rao, et al., 2013)
It is suggested that the augmented jump gap is covered with cross-linked collagen membrane, overlaid by a double layer of PRF and the flap closed by sutures. Studies have demonstrated that the use of leukocyte-platelet rich fibrin (L-PRF or A-PRF) membranes for the stimulation of bone and gingival healing around the implant is particularly significant (Öncü and Erbeyo 2015). The elastic consistency of the PRF membrane allows the clinician to punch a hole in the membrane to facilitate draping the membrane over the healing abutment.
PRF in periodontics
In periodontics, PRF has been used to treat gingival recession, intra-bony defects and periapical lesions.
PRF and Gingival Recession
The root coverage procedures aim to cover the exposed surface to enchance esthetics, relieve hypersensitivity as well as difficulties to maintain an optimal bucco-dental hygiene.
Recently, in order to improve the efficiency of the root coverage treatments and reduce the morbidity of the techniques various alternative are used such as the platelet rich fibrin (PRF) replacing the connective tissue graft. Clinical studies showed that PRF membrane increased gain in width of keratinized gingiva at the test sites at 6 months compared to the modified coronally advanced flap alone. In Jankovic study, the use of PRF membrane in gingival recession treatment provided acceptable clinical results at 6 months compared to connective tissue graft (CTG) treated gingival recessions.
Intra bony defect regeneration
PRF membrane is a solid material with the advantage that it is easy to handle and to position in bony defects. PRF membranes can also be used as a protection membrane after the filling of the intrabony defect.
Clinically, the general concept of “natural tissue regeneration” (NTR) and natural bone regeneration (NBR) (Del Corso, et al., 2012) requires to fill the periodontal intrabony defect with L-PRF, most times in association with a bone substitute used as a solid space maintainer, and then to cover the filled intrabony defect with L-PRF membranes, used for the protection of the grafted area and as a healing booster for the soft tissues above the defects. The objective of this cover is not only to protect the blood clot and/or the filling material, like in the GTR concept, but also to promote the induction of a strong and thick periosteum and gingiva.
The use of PRF in the treatment of intrabony defects has shown significant clinical benefits when compared with open flap debridement alone. Yuchao showed that the use of PRF as the sole grafting material seems to be an effective modality of regenerative treatment for periodontal intrabony defects. Thorat had compared the clinical and radiological effectiveness of autologous PRF gel in the treatment of intra-bony defects of chronic periodontitis patients with conventional periodontal flap surgery alone. He showed a significant reduction in probing depth and clinical attachment level gain both groups (test and control group) when compared with baseline and 9 months.
PRF membranes can also be used as a palatal wound bandage or protection membranes after harvesting connective tissue grafts in the palate (Femminella, et al., 2015; Kulkarni, et al., 2014; Jain, et al., 2012).
Case studies show that PRF membrane used as a palatal bandage is an efficacious approach to protect the raw wound area of a palatal donor site and significantly accelerates palatal wound healing and reduces patient discomfort and healing time (Aravindaksha, et al., 2014; Femminella, et al., 2016).
PRF in Oral Surgery
Most of the evidence-based research in the field of oral surgery is primarily focused on enhancing bone healing (Singh, et al., 2012; Gurbuzer, et al., 2010; Rao, et al., 2013) and reducing postoperative complications following third molar extractions. Research is also emerging on promoting healing of apico-marginal defects in root end surgery. Numerous case and case series studies have been reported that support the use of PRF in various clinical applications in the field of oral surgery.
Post-extraction socket augmentation and healing
The healing and remodeling of an extraction socket is highly dependent on the initial stabilization of the blood clot and the quick gingival wound closure. This can be achieved by placing fibrin plug in the socket (with or without a bone substitute) and closing with a fibrin membrane. The use of PRF as a post extraction sockets filling biomaterial is recommended as a useful procedure in order to reduce the early adverse effects of the inflammation, such as postoperative pain (Eshghpour, et al., 2014; Uyanik, et al., 2015) and to promote the soft tissue healing and bone regeneration process (Manernzi, et al., 2015).
Clinical situations where post-extraction socket augmentation with PRF is specifically indicated are for early or delayed implant placement and immediate post-extraction implant placement (Simon, et al., 2009; Simon, et al., 2011; Triveni, et al., 2012; Rao, et al., 2013; Basarli, et al., 2015).
Reduce post-extraction complications in medically compromised cases
PRF can be used to minimize post-extraction complications such as osteitis, dry or infected sockets resulting from delayed or potentially compromised healing or bleeding situations in systemic conditions such as such as with diabetics, patients receiving oral bisphosphonate medication presenting a risk of osteonecrosis of the jaws, or patients receiving anticoagulants (Sammartino, et al., 2011).
Delayed or compromised healing of extraction sockets is mostly related to an unstable blood clot within the socket. In such case a fibrin clot is simply placed in the socket, covered with a collagen plug or membrane and sutured. Placing PRF in a socket could amplify the natural coagulation process and enhance socket healing.
Prevention of periodontal complications in third molar surgery
Complex third molar extractions frequently result in critical size bone defects and compromised healing impacting negatively on the outcome of periodontal tissues distal of the second molar. When bone defects after extraction are critical-sized (and often associated with cystic lesions), using PRF as a filling material or mixing PRF with a bone substitute in order to use a significant volume of solid biomaterial for filling is considered as reliable option.
These treatments are not, however, simple dental extractions, and are often at the border of guided bone regeneration (GBR) or bone grafting. The use of a PRF as a filling material significantly promotes soft tissue healing and also faster regeneration of bone in these sites and neighboring periodontal tissues (Ruga, et al., 2011; Yelamai and Saikrishna 2014).
Ana B. Castro,Nastaran Meschi,Andy Temmerman,Nelson Pinto,Paul Lambrechts,Wim Teughels,Marc Quirynen: Regenerative potential of leucocyte‐and platelet‐rich fibrin. Part B: sinus floor elevation, alveolar ridge preservation and implant therapy. A systematic review
Ana B. Castro,Nastaran Meschi,Andy Temmerman,Nelson Pinto,Paul Lambrechts,Wim Teughels,Marc Quirynen: Regenerative potential of leucocyte- and platelet-rich fibrin. Part A: intra-bony defects, furcation defects and periodontal plastic surgery. A systematic review and meta-analysis
Drs. Johan Hartshorne and Howard Gluckman: A comprehensive clinical review of platelet-rich fibrin (PRF) and its role in promoting tissue healing and regeneration: part 3
Michael Pikos, Richard J Miron: PRF as a Barrier Membrane in Guided Bone Regeneration
Choukroun J, Diss A, Simonpieri A, et al. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part IV clinical effects on tissue healing. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101(3):299-303.
Choukroun J, Diss A, Simonpieri A, et al. Platelet-rich fibrin (PRF): a second-generation platelet concentrate. Part V: histologic evaluations of PRF effects on bone allograft maturation in sinus lift. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;101:299-303