Use Of Leukocyte- And Platelet-rich Fibrin Research Articles

Instructions for the use of L-PRF in different clinical indications.

Autologous platelet concentrates (APCs) have demonstrated clear benefits across various clinical applications, including alveolar ridge preservation, guided tissue regeneration, guided bone regeneration, sinus floor elevation (both lateral window approach and transcrestal technique), endodontic surgery, the treatment of medication-related osteonecrosis of the jaw bones, and periodontal plastic surgery. To ensure an optimal clinical outcome, clinicians must adhere strictly to the protocol to prepare the APCs and, especially follow evidence-based surgical guidelines, often simple but crucial, to minimize the likelihood of errors. The majority of clinical trials reported on second-generation APCs [the leukocyte- and platelet-rich fibrin (L-PRF) family, including its modifications (A-PRF, A-PRF+, CGF, T-PRF, H-PRF, etc.)]. These second-generation APCs offer additional benefits compared to the first-generation APCs, making them the preferred choice for the development of clinical recommendations. These recommendations have been formulated through a meticulous examination of the available clinical data and the clinical experience of the authors of this paper.

The Role of Leukocyte and Platelet-Rich Fibrin in Enhancing the Healing of Extraction Sockets: An Overview of the Literature

Introduction: Leukocyte and platelet-rich fibrin (L-PRF) is an emerging material in dentistry, however, there are controversies surrounding its effectiveness. Despite the amount of literature available, debates regarding its effect continue. This review aims to summarize and clarify the data surrounding the use of L-PRF in promoting the healing of extraction sockets, which may offer a better outcome for future treatments. Purpose: The purpose of this review is to evaluate the current literature on the use of L-PRF in promoting the healing of extraction sockets, and to provide a comprehensive overview of the available evidence. Methods: A comprehensive computer-based search of databases such as PubMed, Medline, and Cochrane Library was conducted. Results: The results of this review suggest that L-PRF has shown promise in promoting early healing of extraction sockets, but the evidence for its effectiveness over a longer period is limited. Conclusion: Although L-PRF has shown promising results in the early healing periods, its effectiveness over a longer healing period cannot be confirmed based on the available data. More clinical trials with standardized protocols and consistent measurement methods are needed to establish the role of L-PRF in enhancing the healing of extraction sockets.

Treatment of sinus membrane perforations during sinus lift surgeries using leukocyte and platelet-rich fibrin: A report of three cases

Schneiderian membrane (SM) perforation is the most frequent intraoperative complication during sinus lifts, which can lead to implant failure or delayed implant treatment. This article aims to show the results of using leukocyte and platelet-rich fibrin (L-PRF) in the treatment of perforations occurring during sinus lifts with a lateral window approach. Three patients (n = 5 implants) with a mean ± SD age of 57.67 ± 12.12 years were included, in whom perforations of the SM of 3-5 mm and >5 mm occurred. The mean ± SD preoperative bone height was 4.42 ± 2.96 and, at 6 months it was 9.58 ± 2.41 (P < 0.05). All implants had a 100% survival rate at 6-24 months. At the split-mouth, the mean ± SD baseline height was 5.05 ± 2.99 mm in repaired SM versus 2.92 ± 1.01 in those without any complications (P > 0.05). At 6 months, mean ± SD gains were 10.09 ± 2.44 mm versus 7.73 ± 0.90 mm, respectively, (P > 0.05). L-PRF simplifies SM repair, reducing the need for high surgical experience and/or skills. Although there are no significant differences between repaired and intact SM, at the radiological level, greater bone compactness and maturation were observed in the latter, which may be associated with the presence of air bubbles caused by anaerobic bacterial activity in repaired SM. The use of L-PRF greatly simplifies the resolution of SM perforations during sinus lift surgeries, reducing treatment times, and providing predictable results. Being of autologous origin, it accelerates and enhances healing, eliminating the possibility of autoimmune rejection reactions.

Leukocyte- and Platelet-Rich Fibrin: A New Method for Scalp Defect Reconstruction.

Leukocyte- and Platelet-Rich Fibrin: A New Method for Scalp Defect Reconstruction.

Multi-walled carbon nanotube/hydroxyapatite nanocomposite with leukocyte- and platelet-rich fibrin for bone regeneration in sheep model.

The aim of this study was to evaluate the effects of multi-walled carbon nanotubes/hydroxyapatite (MWCNT/HA) granules with or without leukocyte- and platelet-rich fibrin (L-PRF) on bone regeneration in cancellous bone of sheep model. Totally, 32 cylindrical holes were drilled in female sheep (n = 4) in the distal epiphysis and proximal metaphysis of right and left humerus and femur. The defects were randomly filled with (1) MWCNT/HA, (2) MWCNT/HA mixed with L-PRF, (3) L-PRF, and (4) left empty as control. After 8 weeks, defects were evaluated and compared radiographically using multi-slice computed tomographic (CT) scan and cone beam CT scans, histologically and histomorphometrically. The results showed that there was no significant inflammation (> 10%) or foreign body reaction around the granules. The new lamellar bone was regenerated around the MWCNT/HA nanocomposite granules. Addition of L-PRF to MWCNT/HA demonstrated significantly improvement of new bone formation, about 27.40 ± 1.08%, in comparison with the L-PRF alone, about (12.16 ± 1.46%) (P < 0.01). Also, the rate of new bone formation was significantly greater with the use of MWCNT/HA granules (24.59 ± 1.54%) compared to the control (10.36 ± 1.17%) (P < 0.01). Consequently, both biocompatibility and osteoconductivity of MWCNT/HA nanocomposite were demonstrated in the preclinical sheep model, and the use of L-PRF in combination with MWCNT/HA nanocomposite can improve bone regeneration.

Leukocyte and Platelet-Rich Fibrin Have Same Effect as Blood Clot in the 3-Dimensional Alveolar Ridge Preservation. A Split-Mouth Randomized Clinical Trial

Leukocyte- and platelet-rich fibrin (L-PRF) has been used for alveolar ridge preservation (ARP) in postextraction tooth sockets. However, current reports have measured its effectiveness in linear measurements of 3-dimensional ridge preservation. The purpose of this study was to determine the effectiveness of the use of L-PRF filling versus natural clot blood healing in ARP according to the clinical, radiographic, and volumetric measurements of postextraction tooth sockets. A split-mouth randomized clinical trial was designed. Healthy patients who needed bilateral extraction of upper third molars were selected. After the tooth extraction, the socket was filled and distributed randomly with L-PRF and the contralateral socket only with the blood clot. The dimensional change of soft tissue healing around the sockets, and the length, depth, and difference of bone formation were examined using standardized periapical radiographs. Volumetric measurement variation of the sockets was evaluated by 3-dimensional scanning of dental casts. Changes of all measures were analyzed at 7 days (initial) and 3 months (final) after the tooth extraction and compared between both groups (t test; P<.05). Sixteen patients (aged 24.75±3.53years; 56.25% women) participated. Measurements of wound healing and the length, depth, and difference of bone formation were similar for both study groups at initial and final times. The calculation of initial-final volumetric socket variation was 15.45±13.12μL using L-PRF and 14.12±11.23μL using blood clot (P=.78). L-PRF filling showed the same dimensional and volumetric behavior as normal blood clot healing in the ARP of postextraction tooth sockets. Future investigations will have to analyze the use of surgical models and digital instruments in ARP techniques.

Histological comparison of DBBM and platelet rich fibrin for guided bone regeneration in a rabbit model

To histologically evaluate the use of bovine derived deproteinized xenograft (DBBM), leukocyte and platelet rich fibrin (L-PRF) and the combination of both in Guided Bone Regeneration (GBR) performed in non-critical size defects in rabbit. A prospective experimental study was performed. Four bone defects in the tibiae of 12 rabbits were made and each of them was filled with DBBM, L-PRF, a combination of DBBM+L-PRF or was left to heal as control site. All defects were covered with a collagen membrane. Rabbits were randomly distributed in three groups and euthanatized at 3, 6 or 9 weeks. Samples were obtained and histologically analyzed to determine vital bone, connective tissue and remaining graft particles percentage. Analysis of variance, Kruskal Wallis and non-paired t-test where used to evaluate the significance of the results. At 3 weeks of healing, DBBM showed significantly more vital bone percentage than L-PRF (p=0,05) and DBBM+L-PRF showed significantly less connective tissue than control (p<0,05). All other groups showed no statistical difference between them. At 6 weeks of healing, DBBM showed significantly more vital bone percentage than L-PRF (p<0,05), DBBM+L-PRF (p<0,05) and control (p<0,05) and there wasn't any other significant difference regarding to connective tissue or remaining particle percentage between groups. At t 9 weeks healing period, there weren't any significant differences between groups. DBBM seems to enhance vital bone formation at early healing stages. The use of L-PRF alone or combined with DBBM, didn't show any histological improvement regarding to vital bone formation. The use of DBBM, alone or in conjunction with L-PRF showed a trend to reduce connective tissue percentage. The use of L-PRF combined with DBBM didn't affect the remaining particle percentage.

Leukocyte- and platelet-rich fibrin as an adjuvant to the surgical approach for osteoradionecrosis: a case report.

We present a case of osteoradionecrosis treated with leukocyte- and platelet-rich fibrin (LPRF) and surgery and followed up with clinical and tomographic investigations. A 65-year-old woman presented with pain in the posterior region of the right palate. Her medical history included cardiovascular disease and squamous cell carcinoma in the anterior region of the floor of the mouth that had been treated with intensity-modulated radiation therapy. Measurements of isodose curves showed a full dosage of 6,462.6 cGy in the anterior mandibular region, whereas that in the posterior region on the right side of the maxilla reached 5,708.1 cGy. Osteotomy was performed using rotary instruments, and debridement and placement of two LPRF membranes were also carried out. New gum tissue with no bone exposure was noted 14 days postoperatively. Tissue repair was complete, and the patient had no further complaints. During a 39-month follow-up period, the oral mucosa remained intact, and the patient was rehabilitated with a new upper denture. Since there is no consensus regarding the best protocol to treat osteoradionecrosis, LPRF might be an interesting adjuvant to a surgical approach. The use of LPRF is simple and reduces operational costs, time of handling, probability of technical failure, and associated morbidities for patients with osteoradionecrosis.

The use of leukocyte- and platelet-rich fibrin in the management of soft tissue healing and pain in post-extraction sockets: A randomized clinical trial

This study aimed to evaluate the clinical effect of leukocyte- and platelet-rich fibrin (L-PRF) to improve epithelialization and decrease postoperative pain in post-extraction sockets. Thirty two participants requiring extractions of posterior teeth were randomized into two groups: 1) extractions and socket filling with L-PRF membrane (test group) and 2) extraction with spontaneous healing (control group). One week after extraction, an assessment of soft tissue healing around the sockets was performed using the healing index. Also, postoperative pain by visual analog scale (VAS) and number of consumed analgesic tablets were recorded. In the first week, the sockets of the test group presented a significantly (mean of 3.81 ± 0.54; p = 0.0138) higher level of healing when compared to the sockets of the control group (mean of 3.18 ± 0.65). The participants of control group reported a significantly (mean of 5.12 ± 1.08; p = 0.0128) higher level of postoperative pain when compared to the test group (mean of 4 ± 1.15). Also, the control group consumed a greater number of analgesics (mean of 1.75 ± 0.85; p = 0.0136) when compared to the test group (mean of 1 ± 1.15). The results of the present study demonstrate that whenever improved healing of the extraction socket is needed, the use of L-PRF should be considered. In addition, the use of L-PRF decreases postoperative pain and discomfort.

Leucocyte- and platelet-rich fibrin as a rescue therapy for small-to-medium-sized complex wounds of the lower extremities

BackgroundGenerally, advanced wound care resources are applied for complex wounds that pose a challenge to the medical and nursing teams. In this report, the use of leukocyte- and platelet-rich fibrin (L-PRF) is emphasized for complex wounds as an alternative, simple, inexpensive, time-saving process that does not require hospitalization and has a healing potential over that of bare soft tissue, including bone, tendon, and ligaments. The aim of this study is to extend the use of L-PRF in small-to-moderate-sized complex wounds of lower extremities in which L-PRF maintains the sensitive structures viable.MethodsBetween January 2016 and December 2017, 17 small-to-moderate-sized complex wounds of lower extremities treated with L-PRF were recruited from the plastic and reconstructive surgery clinic in Aydin State Hospital, Turkey. The treatment was administered twice per week in the outpatient clinic. Depending on the size and extension of the complex wound, two to five blood samples were collected into 8.5 ml dry, glass vacuum tubes with no anticoagulant, and samples were immediately centrifuged at 1630×g for 5 min to obtain L-PRF. Complete healing was defined as the day of complete wound epithelialization.ResultsThe median values of the initial wound size and wound duration were 12 cm2 (interquartile range, 6 to 23 cm2) and 8 months before first admission (interquartile range, 4 to 18 months), respectively. All wounds showed significant improvements after L-PRF therapy and full closure after a median of 18 months, with an interquartile range of 11 to 34 months of L-PRF applications. There were recurrences of wounds during the first 6 months after therapy. No adverse events were observed.ConclusionsOur results add to the growing evidence that L-PRF treatments protect and maintain bare soft tissue structures viable, facilitate the formation of granulation tissue and epithelization, and remarkably reduce the need for additional soft tissue surgeries in small-to-medium-sized complex wounds.

Leukocyte- and platelet-rich fibrin: a new graft material in endoscopic repair of spontaneous CSF leaks.

Spontaneous CSF leak is a challenging condition, with frequent recurrences following attempted surgical closure. The selection of graft materials depends on the experience of the operating surgeon. Leukocyte- and platelet-rich fibrin (L-PRF) is a second-generation platelet concentrate that has currently invaded every surgical specialty. To our knowledge, no previous reports about the use of L-PRF in repair of CSF leak were published. The study was conducted to assess the potential role of L-PRF in spontaneous CSF leaks repair. This prospective controlled study was conducted on 40 patients who were randomly divided into 2 groups: In group A, L-PRF was used in addition to another layer, while patients in group B underwent multilayer repair using traditional graft materials. Preoperative HRCT scan showed bony dehiscence (n = 30) and opacity in a nearby sinus (n = 9). MRI findings varied between empty sella in 28 patients, and meningocele in 19 patients. Mean preoperatively measured CSF pressure was 26.6cm H2O. Cribriform plate was identified as the commonest site of leaks. Multiple skull defects were detected in 2 cases. Failure of repair was found in 3 patients (15%) of group B and 1 patient (5%) of group A, this difference was statistically insignificant (P value = 0.28). Significance correlation between recurrence of CSF leak and elevated intracranial pressure was observed (P value; 0.04). L-PRF was found to be a good adjunct material in endoscopic spontaneous CSF leaks repair. It helps in decreasing the number of layers needed for defect closure.

Plasma-rich fibrin in neurosurgery: a feasibility study.

Cerebrospinal fluid (CSF) leakage represents an important and sometimes challenging complication in both cranial and spinal surgery. Current available options for dural closure pose inherent problems regarding safety, efficacy, immunogenicity, cost, and invasiveness. In this article, the use of leukocyte- and platelet-rich fibrin (L-PRF) derived from the patient's own blood is proposed to facilitate dural closure. We aim to describe the safety, feasibility, and applicability of L-PRF membranes and plugs in cranial and spinal neurosurgery. A retrospective study reviewing clinical and surgical characteristics was conducted in 47 patients in whom the use of L-PRF was attempted to reinforce dural closure at a single institution during 1year. Procedures included skull base, posterior fossa, and spinal revision surgeries. L-PRF membranes and/or plugs were used in 44 surgeries. The preparation of L-PRF failed in three cases. L-PRF membranes were used as onlay grafts to augment sealing or sutured into a defect. No short-term complications related to the use of L-PRF were recorded. Postoperative CSF leakage was present in two endoscopic transsphenoidal pituitary surgeries and in one spinal CSF leak repair. L-PRF is safe, inexpensive, and completely autologous and can be rapidly and non-invasively harvested to aid in dural closure. Theoretical advantages include a regenerative bioactive potential, which could lead to improved wound healing and reduced infection rates. These findings warrant larger prospective studies to determine the potential role of L-PRF in neurosurgery.

L-PRF for increasing the width of keratinized mucosa around implants: A split-mouth, randomized, controlled pilot clinical trial.

This study aims to evaluate the use of the leukocyte- and platelet-rich fibrin (L-PRF) membranes in increasing the width of the keratinized mucosa (KM) around implants. Eight patients in need for bilateral widening of the KM around implants in the lower jaw were recruited for a spit-mouth randomized controlled trial. At the control site, a free gingival graft (FGG) was used, whereas at the other side (test), L-PRF membranes were applied. The primary outcome was the increase in width of KM around the implants. As secondary outcomes, the postoperative pain and surgical time were assessed. The follow-up period was 6weeks. A significant increase in the total bucco-lingual width of KM in both groups was observed, with 1.3mm±0.9 extra gain (P<.05) for the FGG sites. Shrinkage of the widened areas in this period was 32.1% at the test site and 23.6% at the control site. All values of the postoperative pain scores at the control site were higher than at the test site. The mean surgery time in the test and control group was 29.1±4.8 and 48.1±7.7minutes, respectively. Within the limitations of this randomized controlled trial with split mouth design, it can be concluded that L-PRF can increase the width of KM around implants. Furthermore, the use of L-PRF results in a lower surgical time with less postoperative discomfort and pain for the patients in comparison to the FGG.

Clinical evaluation of autologous platelet-rich fibrin in the treatment of multiple adjacent gingival recession defects: a 12-month study.

Leukocyte- and platelet-rich fibrin (L-PRF) belongs to a new generation of platelet concentrates. There are limited numbers of studies focused on the use of L-PRF in gingival recession defects. This study evaluated the safety and effectiveness of using L-PRF membranes as a substitute for free connective tissue grafts (CTGs) as a treatment method for gingival recession defects. A total of 44 Miller Class I/II gingival recessions that were bilateral, adjacent, and greater than 3 mm in size were selected. Each recession site was randomly assigned to the test group (L-PRF) or the control group (CTG). After 12 months, root coverage was 76.63% and 77.36% in the L-PRF and CTG groups, respectively. It is suggested that L-PRF membrane may be an alternative graft material for treating multiple adjacent recessions greater than 3 mm in size without a requirement for additional surgery.

Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF) in the Healing of Simple Postextraction Sockets: A Split-Mouth Study.

The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF) on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females) were treated with multiple extractions (2 to 8), with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10) at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12). The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation.

Increased vascularization during early healing after biologic augmentation in repair of chronic rotator cuff tears using autologous leukocyte- and platelet-rich fibrin (L-PRF): a prospective randomized controlled pilot trial

We hypothesized that arthroscopic rotator cuff repairs using leukocyte- and platelet-rich fibrin (L-PRF) in a standardized, modified protocol is technically feasible and results in a higher vascularization response and watertight healing rate during early healing. Twenty patients with chronic rotator cuff tears were randomly assigned to 2 treatment groups. In the test group (N = 10), L-PRF was added in between the tendon and the bone during arthroscopic rotator cuff repair. The second group served as control (N = 10). They received the same arthroscopic treatment without the use of L-PRF. We used a double-row tension band technique. Clinical examinations including subjective shoulder value, visual analog scale, Constant, and Simple Shoulder Test scores and measurement of the vascularization with power Doppler ultrasonography were made at 6 and 12 weeks. There have been no postoperative complications. At 6 and 12 weeks, there was no significant difference in the clinical scores between the test and the control groups. The mean vascularization index of the surgical tendon-to-bone insertions was always significantly higher in the L-PRF group than in the contralateral healthy shoulders at 6 and 12 weeks (P = .0001). Whereas the L-PRF group showed a higher vascularization compared with the control group at 6 weeks (P = .001), there was no difference after 12 weeks of follow-up (P = .889). Watertight healing was obtained in 89% of the repaired cuffs. Arthroscopic rotator cuff repair with the application of L-PRF is technically feasible and yields higher early vascularization. Increased vascularization may potentially predispose to an increased and earlier cellular response and an increased healing rate.

Current Knowledge and Perspectives for the Use of Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF) in Oral and Maxillofacial Surgery Part 1: Periodontal and Dentoalveolar Surgery

Platelet concentrates for surgical use are innovative tools of regenerative medicine, and were widely tested in oral and maxillofacial surgery. Unfortunately, the literature on the topic is contradictory and the published data are difficult to sort and interpret. In periodontology and dentoalveolar surgery, the literature is particularly dense about the use of the various forms of Platelet-Rich Plasma (PRP) - Pure Platelet-Rich Plasma (P-PRP) or Leukocyte- and Platelet-Rich Plasma (L-PRP) - but still limited about Platelet-Rich Fibrin (PRF) subfamilies. In this first article, we describe and discuss the current published knowledge about the use of PRP and PRF during tooth avulsion or extraction, mucogingival surgery, Guided Tissue Regeneration (GTR) or bone filling of periodontal intrabony defects, and regeneration of alveolar ridges using Guided Bone Regeneration (GBR), in a comprehensive way and in order to avoid the traps of a confusing literature and to highlight the underlying universal mechanisms of these products. Finally, we particularly insist on the perspectives in this field, through the description and illustration of the systematic use of L-PRF (Leukocyte- and Platelet- Rich Fibrin) clots and membranes during tooth avulsion, cyst exeresis or the treatment of gingival recessions by root coverage. The use of L-PRF also allowed to define new therapeutic principles: NTR (Natural Tissue Regeneration) for the treatment of periodontal intrabony lesions and Natural Bone Regeneration (NBR) for the reconstruction of the alveolar ridges. In periodontology, this field of research will soon find his golden age by the development of user-friendly platelet concentrate procedures, and the definition of new efficient concepts and clinical protocols.

Current Knowledge and Perspectives for the Use of Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF) in Oral and Maxillofacial Surgery Part 2: Bone Graft, Implant and Reconstructive Surgery

Platelet concentrates for surgical use are innovative tools of regenerative medicine, and were widely tested in oral and maxillofacial surgery. Unfortunately, the literature on the topic is contradictory and the published data are difficult to sort and interpret. In bone graft, implant and reconstructive surgery, the literature is particularly dense about the use of the various forms of Platelet-Rich Plasma (PRP) - Pure Platelet-Rich Plasma (P-PRP) or Leukocyte- and Platelet-Rich Plasma (L-PRP) - but still limited about Platelet-Rich Fibrin (PRF) subfamilies. In this second article, we describe and discuss the current published knowledge about the use of PRP and PRF during implant placement (particularly as surface treatment for the stimulation of osseointegration), the treatment of peri-implant bone defects (after peri-implantitis, during implantation in an insufficient bone volume or during immediate post-extraction or post-avulsion implantation), the sinuslift procedures and various complex implant-supported treatments. Other potential applications of the platelet concentrates are also highlighted in maxillofacial reconstructive surgery, for the treatment of patients using bisphosphonates, anticoagulants or with post-tumoral irradiated maxilla. Finally, we particularly insist on the perspectives in this field, through the description and illustration of the use of L-PRF (Leukocyte- and Platelet-Rich Fibrin) clots and membranes during the regeneration of peri-implant bone defects, during the sinus-lift procedure and during complex implant-supported rehabilitations. The use of L-PRF allowed to define a new therapeutic concept called the Natural Bone Regeneration (NBR) for the reconstruction of the alveolar ridges at the gingival and bone levels. As it is illustrated in this article, the NBR principles allow to push away some technical limits of global implant-supported rehabilitations, particularly when combined with other powerful biotechnological tools: metronidazole solution, adequate bone substitutes and improved implant designs and surfaces (for example here AstraTech Osseospeed or Intra-Lock Ossean implants). As a general conclusion, we are currently living a transition period in the use of PRP and PRF in oral and maxillofacial surgery. PRPs failed to prove strong strategic advantages that could justify their use in daily practice, and the use of most PRP techniques will probably be limited to some very specific applications where satisfactory results have been reached. Only a few simple, inexpensive and efficient techniques such as the L-PRF will continue to develop in oral and maxillofacial surgery in the next years. This natural evolution illustrates that clinical sciences need concrete and practical solutions, and not hypothetical benefits. The history of platelet concentrates in oral and maxillofacial surgery finally demonstrates also how the techniques evolve and sometimes promote the definition of new therapeutical concepts and clinical protocols in the today's era of regenerative medicine.

The Use of Leukocyte- and Platelet-Rich Fibrin During Immediate Postextractive Implantation and Loading for the Esthetic Replacement of a Fractured Maxillary Central Incisor

I mplant-supported restoration of the maxillary anterior segment that is biologically, functionally, and esthetically acceptable following traumatic injuries in the maxillary anterior segment is always complex. Careful extraction of the fractured root, residual labial bone preservation, proper flap design, ideal positioning of the implant, appropriate softtissue contour, and the crown emergence are all important steps necessary to achieve a predictable, stable, functional, and esthetic success. However, healing of the tissues is always difficult to control and the development of new techniques and materials to improve these treatments is still necessary. The use of platelet concentrates is an interesting approach. Platelet concentrates for surgical use are widely used and continuously investigated in oral and maxillofacial surgery. The objective is to gather platelet growth factors and to inject them on a surgical site to stimulate the healing process. A significant percentage of the literature is focused on the platelet-rich plasma (PRP) families. PRP is a liquid platelet suspension often activated into a platelet-rich gel (like fibrin glues). Another technology called leukocyteand platelet-rich fibrin (L-PRF) allows for the preparation of strong fibrin membranes enriched with cells (activated platelets, leukocytes, circulating cells) and platelet growth factors. This autologous healing biomaterial is free of additives (no anticoagulant during blood harvest, no chemicals for activation), simple, inexpensive, and quick to prepare (15 minutes for all steps). This technique is specifically adapted to the practical needs in daily implant dentistry. Several articles have reported the use of these L-PRF membranes for the stimulation of bone and 1 Private practice, Turin, Italy. 2 Private practice, Ra’anana, Israel. 3 Clarion Research Group, Clarion, Penn. Department of Restorative Dentistry, State University of New York at Buffalo, Buffalo, NY. 4 LoB5 Unit, Research Center for Biomineralization Disorders, School of Dentistry, Chonnam National University, Gwangju, South Korea. Department of Stomatology, Oral Surgery, and Dental and MaxilloFacial Radiology, School of Dental Medicine, University of Geneva, Geneva, Switzerland. * Corresponding author, e-mail: LoB5@mac.com DOI: 10.1563/AAID-JOI-D-12-CL.3802

The Future of Platelet Concentrates in Sports Medicine: Platelet-Rich Plasma, Platelet-Rich Fibrin, and the Impact of Scaffolds and Cells on the Long-term Delivery of Growth Factors

Platelet concentrates for musculoskeletal injuries are innovative tools for regenerative medicine. Some interesting preliminary results have been described in sports medicine, yet little is known about the respective biological properties of the many different products available. Techniques have been classified into 4 main families with different fibrin architecture and cellular content and thus with different potential clinical applications. The pure platelet-rich plasma (P-PRP) and leukocyte- and platelet-rich plasma (L-PRP) are platelet suspensions, respectively, without and with leukocytes that can be used as liquid injectable preparations in injured tendons or articulations. In an open surgical site, these products can be activated into a fibrin gel that offers additional local antihemorrhagic and sealing properties. On the contrary, the pure platelet-rich fibrin (P-PRF) and leukocyte- and platelet-rich fibrin (L-PRF) are solid fibrin-based products, respectively, without and with leukocytes, which can be used as bioactive healing biomaterials in a surgical site. In this article, the significant differences between the numerous available products are emphasized. The comparison of the slow release of some key growth factors and coagulation/matrix proteins from L-PRF and P-PRP gel (preparation rich in growth factors [PRGF]) membranes during 7 days in vitro shows the different biological signatures of these 2 families of products and indicates that each technique should be fully characterized before investigating their potential clinical effects. If injectable platelet suspensions are to be beneficial in sports medicine as regenerative cocktails, it is important to remember that all platelet concentrates are in fact blood-based engineered tissues, and their effects are therefore much more complex to control than a classic pharmacologic treatment. The use of solid scaffolds for the long-term delivery of growth factors is a new approach, particularly the use of L-PRF as a regenerative in situ tissue engineering method during the treatment of tendinopathies of the quadriceps and the patellar tendon and for regenerative stimulation in rotator cuff repair or in anterior cruciate ligament repair. Finally, the future of these technologies in sports medicine requires an understanding of these complex materials, the engineering of the adequate regenerative material on demand, and knowledge of how to use them in the clinical situation.