Enhance Healing Using Leukocyte Platelet Rich Fibrin

New techniques in dental treatment are constantly being developed. Oral health professionals need to remain aware of these advances to promote the best possible patient outcomes. Today, treatment modalities can assist with the stimulation of tissue formation after dental surgical procedures. The placement of leukocyte platelet rich fibrin (L-PRF), taken from the patient’s own tissue, provides enhanced healing following specific dental procedures. Acting as a biologic modifier, L-PRF mimics and prolongs the effects of typical physiological wound healing. By releasing the cytokines and platelets necessary for healing over an extended period, recovery begins more rapidly and occurs at a faster rate. This is important in dentistry because many procedures require multiple steps before completion, with each step building and relying on the success of the prior one.

The L-PRF technique was first described by Choukroun in 2001.¹ It is an inexpensive technique using the patient’s blood to create a leukocyte fibrin rich substrate that can be placed in areas of the surgical site in conjunction with supplemental tissue to stimulate bone and soft tissue formation.² The use of L-PRF can provide the patient with enhanced healing, possibly fewer appointments, and a faster end result. As this procedure may reduce the risk of infection and complications, it has a variety of applications in clinical practice.

There are many circumstances in which a patient may require a bone/tissue graft or other treatment to induce new bone/tissue growth. Several types of bone grafting procedures are available, each with its advantages and disadvantages. These constraints encourage the continual development of new alternatives. Although this technique has its detractors, various disciplines have used L-PRF as a biological modifier in many types of surgery, including periodontal, dental implant and maxillofacial surgery.³

Weinberg et al³ define a graft as “any tissue or organ used for implantation or transplantation.” Grafts can use human, animal or synthetic substitutes to stimulate growth. They are divided into four categories based on the origin of the donor material: autografts, allografts, alloplasts, and xenografts.³

Autografts and allografts are associated with human donors. An autograft is tissue taken from and placed in the same individual. These have the highest potential for success because the tissue is obtained from the recipient. Unfortunately, this is not always an option, leaving an allograft as the next option. Allografts are retrieved from a donor and placed in a different individual of the same species. They typically consist of tissue that is taken from a cadaver. Similar to the autograft, allograft studies have shown high success rates and enhanced tissue growth.³

Alloplasts are synthetic tissue substitutes made of nonvital materials. They offer a support system for surrounding structures and encourage tissue to grow around them, but they do not contain factors for cells to induce bone (unlike a tissue-derived graft). Alloplasts carry no risk of disease transmission and the patient does not have to undergo additional procedures to collect donor tissue. Xenografts are tissue substitutes taken from a different species, such as bovine.³

Because L-PRF is an autologous biologic modifier obtained from the patient’s blood, it provides a condensed network of fibrin that is saturated with cytokines, growth factors and platelets.⁴ In short, it speeds up the initial healing process of tissue repair and is capable of generating soft tissue and bone; L-PRF can be used alone or in conjunction with a bone substitute. There are many circumstances in which tissue growth needs to be supported for the success of a procedure.

PROCEDURAL STEPS

An L-PRF procedure is relatively simple and begins with a blood draw. Approximately 9 to 10 ml of blood is drawn with a 24-gauge butterfly needle and placed in a glass tube.² The glass tube is needed to achieve clot polymerization.⁵ Correct handling of the blood is a significant factor in L-PRF treatment success. The blood must be immediately transferred to a centrifuge, which is activated for approximately 12 minutes, without the addition of an anticoagulant.^6,7 During the centrifuge process, the blood coagulates and separates into three layers. Composed of red blood cells, the bottom layer is discarded. The top layer is cell-free and is also discarded. The middle layer is a mesh network that contains the majority of the platelets and fibrin. Within this middle layer, platelets lead to synthesizing growth factors in response to clotting.⁸ The fibrous middle layer also acts as a scaffold when placed for surgical dental treatment, leading to the initiation of tissue response.⁹ This layer can be compressed into a membrane or shaped into a plug, depending on the treatment needed. This clot can be converted into a membrane by compression between two sterile gauzes or by using a specific tool for collection.¹ The fibrin is easily manipulated and placed, allowing it to be used with many dental treatment options.

Once placed, the L-PRF continues to release growth factors for up to seven days, which speeds up healing time. The cost for this procedure is lower than other options for patients because fewer materials are needed and the patient supplies his or her own blood for the procedure. Additionally, because the tissue (i.e., blood) is taken from the patient, its use reduces the risk of infection and disease transmission, which diminishes the chance of rejection.

APPLICATIONS AND RESEARCH

The L-PRF technique has numerous clinical applications, including soft tissue and bone regeneration, extraction socket and alveolar ridge preservation,⁶ horizontal and vertical ridge augmentation, improvement of three-wall infrabony defects,¹⁰ sinus lift procedures for implant placement,² periodontal tissue regeneration,¹¹ improvement of furcation defects,¹² assisting with repair of mandibular fracture sites,⁸ and stimulation of enhanced repair when used in combination with bone substitute or autologous bone.^13–15

Temmerman et al⁶ conducted a case study to determine the success of placing L-PRF in an extraction site to aid in alveolar ridge preservation. The study included 22 subjects who were monitored after extractions. It utilized a split-mouth randomized controlled clinical approach that compared a control group using no membrane in the extraction sites with sites undergoing the L-PRF membrane. Alveolar ridge levels of the extraction sites were compared using cone beam computed tomography. Each tooth was extracted and blood drawn to be centrifuged. The L-PRF membrane was isolated, compressed, and placed in the extraction sites with subsequent suturing. Patients were prescribed a 0.12% chlorhexidine spray for use twice a day and seen seven days later to monitor healing and remove sutures.⁶

At the follow-up appointment, patients reported discomfort following the procedure. The majority of extraction sites revealed a healing site that showed no signs of abnormality. Cone beam computed tomograms were taken immediately after the extraction and three months after treatment to track the progress. These images were then superimposed to analyze the measurement of alveolar ridge present immediately after the extraction and at the three-month follow-up visit. Data showed that the sites where L-PRF was placed had a statistically higher success rate than those sites without. The researchers found a strong statistical correlation associated with the placement of L-PRF in extractions sites with improved healing when compared to those without.⁶

El Kenawy et al¹⁶ conducted a study with 15 patients that analyzed the placement of L-PRF in an extraction site while simultaneously placing an implant. Similar to other studies, each patient rinsed with chlorhexidine gluconate prior to the procedure. A flap was reflected and the tooth extracted. The socket was then irrigated and curetted thoroughly. Each site for implant insertion was continuously irrigated while being drilled to necessary dimensions based on implant size. Implants were inserted 2 to 3 mm beyond the original apex level to aid in stability. Following this, the space left between the socket wall and implant was packed with deproteinized bovine bone material, and an L-PRF membrane positioned and sutured in place.¹⁶

Following treatment, each patient was prescribed 500 mg of amoxicillin for five to seven days. Oral hygiene instructions were demonstrated and a soft food diet was recommended for the next week to two weeks. The sutures were removed seven days posttreatment, and exams were scheduled every week for the following three weeks. After four to six months, the patients returned for healing cap placement, and again two weeks later for abutment delivery. The implants were reassessed every three months over a 1-year period. Implant success was evaluated based on stability, sulcular bleeding, peri-implant pocket depth and radiographic findings. Results of this study revealed a 100% success rate, with ideal osseointegration and a reduction in postoperative problems.¹⁶ While implant therapy is highly successful with the conventional approach, L-PRF — when used as a biological modifier — can improve wound healing and decrease postsurgical discomfort.

USE IN THREE-WALLED BONY DEFECTS

Sharma and Pradeep¹⁰ conducted a study on the effects of placing L-PRF in three-walled bony defects in patients with chronic periodontitis. During the study, 56 defects were treated by adding L-PRF while conducting open-flap debridement or performing open-flap debridement without the addition of L-PRF. Periodontal attachment levels and probing depths were documented with measurements at baseline and nine months posttreatment. Periodontal dressing and sutures were removed after two weeks. A regimen of 0.12% chlorhexidine rinse was also implemented during this time. After two weeks, self-care was performed using a soft toothbrush and gentle brushing. No subgingival instrumentation occurred during the nine months. Posttreatment values showed probing depths improved for the test group (approximately 4.55 mm versus 3.21 mm for the control group). Periodontal attachment levels also improved when L-PRF was added (value for the test group was 3.31 mm versus 2.77 mm in the control group). Additionally, test sites showed an approximate 48.26% greater bone production for filling the site versus 1.8% for those sites in which L-PRF was not placed. When comparing the two methods of treatment, it was found that when L-PRF was used, probing depths decreased, periodontal attachment level increased, and more bone was generated than when performing conventional open-flap debridement.¹⁰

In another study, Sharma and Pradeep¹² evaluated the effects of placing L-PRF in Class II furcation defects when conducting open-flap debridement in comparison to open-flap debridement alone. Thirty-six defects were treated with one of these approaches. Plaque index, sulcus bleeding index, probing depth, clinical attachment level, gingival marginal level, and radiographic bone analysis were compared using baseline and nine month postoperative measurements. Periodontal dressing and sutures were removed after two weeks while using 0.12% chlorhexidine rinse during this time. Self-care was also performed using a soft toothbrush and gentle brushing. No subgingival instrumentation occurred for nine months. The data indicated a greater reduction of probing depth was found for the L-PRF clinical group, with a difference of 2.17 mm as compared with the non L-PRF control group. The test group also showed a significantly greater vertical defect fill (50.8 +/- 6.24) when compared with the control sites (16.7 +/- 6.42) at the nine-month recare appointment. Upon evaluation, both clinical and radiographic parameters indicated drastic improvement observed at those areas treated with L-PRF and open-flap debridement when compared with only open-flap debridement.¹²

A study by Al-Khawlani et al⁸ examined the benefits of L-PRF when placed at sites of mandibular fracture. When L-PRF was placed in close proximity to bone, enhanced bone development occurred. A group of patients (ranging in age from 20 to 42) with mandibular fractures participated as subjects. The L-PRF was applied along the fracture line of the mandible, as plates were used to stabilize it. Patients were evaluated over six months postsurgery. The results indicated that L-PRF placement enhanced osteoblast and bone formation, leading to improved healing. This autologous procedure led to more stable bone regeneration.⁸

SINUS LIFTS

Sinus lifts are most commonly done so there is enough bone available to place an implant. A study by Mazor et al¹ determined the success of using L-PRF in a simultaneous sinus lift and implant placement procedure. Sinus lifts are necessary when a natural tooth has been lost and the maxillary sinus, covered by the Schneiderian membrane, pneumatizes — preventing bone formation. A sinus lift is performed to lift this membrane to allow more space for bone. Additionally, bone or bone grafting material is placed to encourage bone growth in the area to stabilize the site for a future implant.¹ Typically, the graft must be placed four to six months prior to implant placement; however, new methods are improving the success of completing both procedures at the same time.

The L-PRF technique is useful during sinus lift procedures, especially when bone is needed for implant placement. Data were collected from 20 subjects via 25 sinus elevations and the placement of 14 implants.¹ There was no control group, but participants had to be in good health and meet certain criteria. All implants were similar in length and width, and there was approximately 2.9 mm of bone height remaining in each edentulous area. A full tissue flap was elevated and an ultrasonic lancet used to open a bony window. The Schneiderian membrane was delicately lifted and the bony window left attached to support the new sinus floor. This protects the sinus membrane and promotes space maintenance. Several vials of blood (72 ml) were taken from each subject and centrifuged. The PRF clots were removed and membranes compressed to be placed in each sinus. One to two PRF membranes were placed on the Schneiderian membrane in case there were any undetectable perforations created during the procedure. The implants were placed with the tips acting in a manner to hold the new sinus floor in place. One to two additional PRF membranes were placed over the window before the flap was replaced to prevent invagination of the gingival mucosa. Patients were put on a 14-day chlorhexidine gluconate rinse regimen, six days of amoxicillin, and instructed to take ibuprofen as needed.¹

As expected, eight to 10 days following the procedure, a panoramic radiograph revealed no obvious change in bone density; however, six months later, the treated sites were filled with a dense bone-like tissue. Participants described minimal discomfort and all implants presented as stable. Six months posttreatment, the procedure was deemed 100% successful by Mazor et al.¹ While some studies show that the use of implants to “tent up” the sinus membrane through elevation without L-PRF can be successful in stimulating bone to fill the area, the authors concluded L-PRF was an optimal addition to this procedure to improve natural bone regeneration around implants.¹

CONCLUSION

Although not all studies have reported predictably favorable outcomes, clinical results have demonstrated the efficacy of L-PRF in a variety of common dental procedures. The use of L-PRF as a biological modifier stimulates tissue and leads to the improvement of tooth support and maintenance. It is an added treatment modality to make the surgical and healing process easier on the patient. Using the patient’s own tissue greatly aids in a quicker healing and reduces the risk of infection.

As a biologic modifier, L-PRF seems to have limitless possibilities when it comes to bone and soft tissue regeneration and overall healing. Studies with control and test groups show that implant placement, as well as various other dental treatments, can still be consistently successful without the use of L-PRF, but the improved results when L-PRF is used are statistically significant. Areas for future research should investigate its use in various other bone grafting procedures, such as cleft palate repair, distraction osteogenesis, and treatment of osteonecrosis of the jaw. Additionally, further research may find that this technique could be used to stimulate gingival growth and aid in the repair and/or regeneration of attachment loss caused by periodontal disease.

One of oral health professionals’ primary objectives is to educate patients and discuss all treatment options. As such, clinicians should remain aware of viable treatment alternatives that could contribute to improved outcomes. In this light, L-PRF is an advantageous technique that provides optimal results when utilized in conjunction with many dental procedures.

REFERENCES

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From Decisions in Dentistry. December 2017;3(12):40—43.