Platelet-rich fibrin membranes as scaffolds for periosteal tissue engineering

The effect of platelet-rich fibrin on autologous osteochondral transplantation: An in vivo porcine model

BACKGROUND

This work aimed to evaluate the efficacy of cartilage transplantation to the medial femoral condyle±platelet-rich fibrin (PRF) augmentation in a porcine model. The hypothesis of the study was that PRF may act as a bioactive cell scaffold to fill defects and enhance cartilage regeneration.

METHODS

Thirty-two knees of 16 miniature pigs were randomly assigned to four groups. The critical-size osteochondral defects (8x5mm) in femoral condyle of both knees were treated with one of the following: group 1－untreated controls; group 2－cartilage fragments alone; group 3－PRF alone; group 4－PRFT+cartilage fragments. After completion of the surgical implantation, the periosteal patch harvested from the proximal tibia was sutured onto the cartilage of the medial condyle to cover the implanted defects. Animals were sacrificed at six months after treatment. The regenerated cartilages were assessed by gross inspection and histological examination.

RESULTS

The best results were obtained with the repair tissue being hyaline-like cartilage (group 4). The grading score of histological evaluation demonstrated that group 4 had better matrix, cell distribution and cartilage mineralization than group 2 and group 3. PRF showed a positive effect on the cartilage repair; the procedure was more effective when PRF was combined with autologous chondrocytes.

CONCLUSIONS

This approach may provide a successfully employed technique to target cartilage defects in vivo. Larger groups and longer periods of study may provide more definitive and meaningful support for using this therapeutic approach as a new way of cartilage regeneration.

Platelet-rich Fibrin: A Paradigm in Periodontal Therapy - A Systematic Review

Periodontal tissue regeneration has always been a challenge for the periodontists owing to its structural complexity. Although with tissue engineering as a growing multidisciplinary field, this aim has partially been fulfilled. In recent years, platelet-rich fibrin (PRF) has gained wide attention for its utilization as a biocompatible regenerative material not only in dental but also in medical fields. The following systematic review has gathered all the currently available in vitro, animal, and clinical studies utilizing PubMed electronic database from January 2006 to August 2016 highlighting PRF for soft and hard tissue regeneration and/or wound healing. Although results are encouraging but require further validation from clinical studies to justify the potential role of PRF in periodontal regeneration so that this relatively inexpensive autologous biomaterial can be utilized at a wider scale.

A New Method to Develop Human Dental Pulp Cells and Platelet-rich Fibrin Complex

INTRODUCTION

Platelet-rich fibrin (PRF) has been used as a scaffold material in various tissue regeneration studies. In the previous methods to combine seed cells with PRF, the structure of PRF was damaged, and the manipulation time in vitro was also increased. The objective of this in vitro study was to explore an appropriate method to develop a PRF-human dental pulp cell (hDPC) complex to maintain PRF structure integrity and to find out the most efficient part of PRF.

METHODS

The PRF-hDPC complex was developed at 3 different time points during PRF preparation: (1) the before centrifugation (BC) group, the hDPC suspension was added to the venous blood before blood centrifugation; (2) the immediately after centrifugation (IAC) group, the hDPC suspension was added immediately after blood centrifugation; (3) the after centrifugation (AC) group, the hDPC suspension was added 10 minutes after blood centrifugation; and (4) the control group, PRF without hDPC suspension. The prepared PRF-hDPC complexes were cultured for 7 days. The samples were fixed for histologic, immunohistochemistry, and scanning electron microscopic evaluation. Real-time polymerase chain reaction was performed to evaluate messenger RNA expression of alkaline phosphatase and dentin sialophosphoprotein. Enzyme-linked immunosorbent assay quantification for growth factors was performed within the different parts of the PRF.

RESULTS

Histologic, immunohistochemistry, and scanning electron microscopic results revealed that hDPCs were only found in the BC group and exhibited favorable proliferation. Real-time polymerase chain reaction revealed that alkaline phosphatase and dentin sialophosphoprotein expression increased in the cultured PRF-hDPC complex. The lower part of the PRF released the maximum quantity of growth factors.

CONCLUSIONS

Our new method to develop a PRF-hDPCs complex maintained PRF structure integrity. The hDPCs were distributed in the buffy coat, which might be the most efficient part of PRF.

Autologous Platelet-Rich Fibrin in the Treatment of 3-Wall Intrabony Defects in Aggressive Periodontitis: A Randomized Controlled Clinical Trial

BACKGROUND

Platelet-rich fibrin (PRF) has recently been applied in osseous regeneration. The aim of the present study is to explore the efficacy of PRF in treatment of intrabony defects (IBDs) in aggressive periodontitis.

METHODS

Fifty-four IBDs in 17 patients were treated either with autologous PRF with open flap debridement (OFD) or OFD alone. Clinical and radiologic parameters such as probing depth (PD), clinical attachment level (CAL), IBD depth, and percentage defect change were recorded at baseline and 9 months postoperatively.

RESULTS

Mean PD reduction and mean CAL gain were significantly greater in PRF compared with the control group. Furthermore, a significantly greater percentage of mean bone defect change was found in the PRF group.

CONCLUSION

Within the limits of the present study, there is greater bone fill at sites treated with PRF with conventional OFD than conventional OFD alone.

Synergistic effects of the combined use of human-cultured periosteal sheets and platelet-rich fibrin on bone regeneration: An animal study

A human-cultured alveolar bone-derived periosteal (hCP) sheet is an osteogenic grafting material used clinically in periodontal regenerative therapy, while platelet-rich fibrin (PRF), a platelet concentrate with fibrin clot, is considered to augment the wound healing process. Therefore, whether the combined use of hCP-PRF complex could facilitate bone regeneration synergistically was evaluated in animal models. Human periosteal segments (1 × 1 mm) were cultured initially on plastic dishes and formed an hCP sheet. The hCP sheet was implanted with freshly prepared human PRF into subcutaneous tissue (hCP: n = 4, hCP + PRF: n = 4) and 4 mm diameter calvarial bone defect models (hCP: n = 4, hCP + PRF: n = 4, control [defect-only]: n = 4) that prepared in nude mice. At 4 weeks postimplantation, new bone formation was evaluated by using μCT. Cell growth and neovascularization were evaluated by histochemical and immunohistological methods. In the subcutaneous tissue, mineral deposit formation, collagen deposition, and number of vessels were higher in the hCP + PRF group than in the hCP alone group. In the calvarial defect models, new bone formation was significantly higher in the hCP + PRF group than in the hCP alone group and defect-only control group. The numbers of vessels and PCNA-positive cells in calvarial defects were also increased in the hCP + PRF group more than in the hCP alone group. Platelet-rich fibrin preparations support the proliferation and the growth of periosteal cells to form well-combined active biological materials. Platelet-rich fibrin also stimulates the local angiogenesis in the implantation site. Therefore, the combined use of hCP and PRF could be clinically applicable in bone regeneration therapy.

Evolution, current status and advances in application of platelet concentrate in periodontics and implantology

Platelet concentrates (PC) [platelet-rich plasma (PRP) and platelet-rich fibrin (PRF)] are frequently used for surgical procedures in medical and dental fields, particularly in oral and maxillofacial surgery, plastic surgery and sports medicine. The objective of all these technologies is to extract all the elements from a blood sample that could be used to improve healing and promote tissue regeneration. Although leukocyte rich and leukocyte poor PRP’s have their own place in literature, the importance of non-platelet components in a platelet concentrate remains a mystery. PC have come a long way since its first appearance in 1954 to the T-PRF, A-PRF and i-PRF introduced recently. These PC find varied applications successfully in periodontics and implant dentistry as well. However, the technique of preparation, standing time, transfer process, temperature of centrifuge, vibration, etc., are the various factors for the mixed results reported in the literature. Until the introduction of a proper classification of terminologies, the PC were known by different names in different countries and by different commercial companies which also created a lot of confusion. This review intends to clarify all these confusion by briefing the exact evolution of PC, their preparation techniques, recent advances and their various clinical and technical aspects and applications.

Histological evaluation of effectiveness of platelet-rich fibrin on healing of sinus membrane perforations: A preclinical animal study

The aim of this study was to evaluate the effectiveness of platelet-rich fibrin (PRF) in repairing of Schneiderian membrane perforations in rabbit maxillary sinus. A total of 42 female New Zealand rabbits were randomly divided into two groups. Symmetrical bony defects were created 1 cm in diameter and the sinus membranes were exposed. The Schneiderian membranes were elevated in both sinuses and each membrane was perforated with a 1 cm incision. No treatment was applied to the right perforations in both groups. Left-sided perforations were closed with collagen membrane in the first group and PRF membrane in the other group. Seven animals randomly selected from each group were sacrificed at weeks 1, 2 and 4 in order to be able to examine the amounts of lymphocytes, fibroblasts, veins, and collagen fibers in the area where the membranes were applied. Histological analyses showed that there were no statistically significant differences between the collagen membrane and the PRF membrane in the healing of sinus perforation area. PRF may be considered as an alternative application to collagen membrane in sinus membrane perforations.

The effect of L-PRF membranes on bone healing in rabbit tibiae bone defects: micro-CT and biomarker results

More insight into the biological fundamentals of leukocyte platelet-rich fibrin (L-PRF) guided healing is necessary to recommend its application, in particular in deficient bone sites that need to support implants. This study investigated the short-term bone healing effect of L-PRF treatment in cylindrical non-critical sized bone defects with 3 mm diameter and 6 mm depth in tibiae of 18 adult male New Zealand White rabbits. After a randomization process, 96 bone defects were prepared and half of them were filled with a L-PRF membrane, while untreated defects in the opposite tibia served as control group. The rabbits were euthanized after 7, 14 or 28 days of healing. The bone healing of the cortical and medullary areas was investigated by micro-CT, while the expression of molecular markers (RUNX2, VEGFA, COL1A2 and BMP2) was assessed by qRT-PCR. Treatment with L-PRF did not affect the micro-structural bone characteristics of the repaired bone tissue, except for a decrease in the trabecular connectivity at the cortical level after 14 days of healing. At this time, RUNX2 and VEGFA mRNA levels were significantly lower in the treated defects. L-PRF membranes thus had a temporary negative influence on the bone microarchitecture (Tb.Pf) and on the RUNX2 and VEGFA expression during early bone healing. Overall, L-PRF treatment did not enhance bone regeneration in these non-critical size defects after 28 days.

Clinical and immunohistochemical performance of lyophilized platelet-rich fibrin (Ly-PRF) on tissue regeneration

BACKGROUND

Platelet-rich fibrin (PRF) has been widely used in oral implantology and other fields, but benefits of the fresh PRF (FPRF (fresh platelet-rich fibrin)) were consequently limited because of its short-term application. Thus, a protocol for the combination of PRF and lyophilization comes up in the present study to address the issue of PRF storage and delayed clinical application, which has little been reported in this field at home and abroad by now.

PURPOSE

The aim of the present study was to evaluate the applicability of lyophilized platelet-rich fibrin (Ly-PRF) used as the scaffold material for craniofacial tissue regeneration and to compare its biochemical properties with commonly used fresh PRF.

MATERIALS AND METHODS

Two volunteers with both genders were selected as the source of PRF and Ly-PRF samples. Macro- and micro-scopic appearance evaluation as well as immunohistochemical comparison were performed on PRF samples before and after freeze-drying at -196°C. The second experimental phase was to observe clinical performance when fresh and lyophilized PRF were applied in guided bone regeneration (GBR) operations in 39 patients losing teeth in the anterior maxillary region who required an oral implantation followed by labial bone grafting.

RESULTS

The conventional histological and transmission electron microscopy images showed the microstructure of Ly-PRF, which resembled a mesh containing apparently irregularly shaped platelets with less alpha-granule than fresh PRF in micro and a translucent membrane with less elasticity than fresh PRF in macro. Simultaneous immunohistological staining results showed positive expression of PDGF-BB, IL-1, IL-4, TNF, TGF-β₁ in both fresh and lyophilized PRF, while the expression of PDGF-BB, IL-1, TNF, TGF-β₁ has no statistical difference between them (P > .05) but that of IL-4 in Ly-PRF is statistically higher than in fresh PRF (P < .05). When applied in GBR operations, there were no significant differences between Ly-PRF and FPRF in factors of histological and clinical evaluations (i.e., color, swelling, bleeding of the mucosa, pain leveland, and remodeling of hard tissue) performed 3 days, 7 days, and 4 months after the surgery (P > .05).

CONCLUSIONS

This study strongly supports that lyophilization at -196°C does not largely influence the expression of bioactive factors, the microstructure of fibrinogen or the clinical effects of PRF.

Comparison of the Mechanical Properties of Early Leukocyte- and Platelet-Rich Fibrin versus PRGF/Endoret Membranes

Objectives. The mechanical properties of membranes are important factors in the success of treatment and clinical handling. The goal of this study was to compare the mechanical properties of early leukocyte- and platelet-rich fibrin (L-PRF) versus PRGF/Endoret membrane. Materials and Methods. In this experimental study, membranes were obtained from 10 healthy male volunteers. After obtaining 20 cc venous blood from each volunteer, 10 cc was used to prepare early L-PRF (group 1) and the rest was used to get a membrane by PRGF-Endoret system (group 2). Tensile loads were applied to specimens using universal testing machine. Tensile strength, stiffness, and toughness of the two groups of membranes were calculated and compared by paired t-test. Results. The mean tensile strength and toughness were higher in group 1 with a significant difference (P < 0.05). The mean stiffness in group 1 was also higher but not statistically significant (P > 0.05). Conclusions. The results showed that early L-PRF membranes had stronger mechanical properties than membranes produced by PRGF-Endoret system. Early L-PRF membranes might have easier clinical handling and could be a more proper scaffold in periodontal regenerative procedures. The real results of the current L-PRF should be in fact much higher than what is reported here.

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing

AIM

The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients.

MATERIALS AND METHODS

Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3^rd, 7^th, and 14^th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients.

RESULTS

Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site.

CONCLUSION

Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials.

Management of Radicular Cyst Using Platelet-Rich Fibrin & Iliac Bone Graft - A Case Report

Radicular cyst is one of the most commonly occurring cyst in the oral cavity it is usually preceded by trauma or an infectious condition which is followed by enlargement. In recent times there are several treatment procedures that are being applied in order to improve the postoperative condition and to accelerate the process of healing and regeneration in the affected site. A 22-year-old patient reported to our OPD with the chief complaint of swelling on the left side of the face since 2-3 months, on investigating it was diagnosed as Radicular cyst which was initially treated by endodontic treatment of the involved tooth followed by enucleation of the cyst further an apicoectomy was done. Finally a PRF and iliac crest graft was placed for aesthetic rehabilitation with 21.

Clinical and radiographic evaluation of nanocrystalline hydroxyapatite with or without platelet-rich fibrin membrane in the treatment of periodontal intrabony defects

Background:

Nano-sized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties. Nanocrystalline hydroxyapatite (NcHA) binds to bone and stimulate bone healing by stimulation of osteoblast activity. Platelet-rich fibrin (PRF), an intimate assembly of cytokines, glycan chains, and structural glycoproteins enmeshed within a slowly polymerized fibrin network, has the potential to accelerate soft and hard tissue healing. The present study aims to explore the clinical and radiographical outcome of NcHA bone graft with or without PRF, in the treatment of intrabony periodontal defects.

Materials and Methods:

In a split-mouth study design, 20 patients having two almost identical intrabony defects with clinical probing depth of at least 6 mm were selected for the study. Selected sites were randomly divided into two groups. In Group I, mucoperiosteal flap elevation followed by the placement of NcHA was done. In Group II, mucoperiosteal flap elevation, followed by the placement of NcHA with PRF was done. Clinical and radiographic parameters were recorded at baseline and at 6-month postoperatively.

Results:

Both treatment groups showed a significant probing pocket depth (PPD) reduction, clinical attachment gain, increase bone density 6-month after surgery compared with baseline. However, there was a significantly greater PPD reduction and clinical attachment gain when PRF was added to NcHA.

Conclusion:

The NcHA bone graft in combination with PRF demonstrated clinical advantages beyond that achieved by the NcHA alone.

Comparative evaluation of platelet-rich fibrin with demineralized freeze-dried bone allograft in periodontal infrabony defects: A randomized controlled clinical study

INTRODUCTION

Several bone graft materials have been used in the treatment of infrabony defects. Demineralized freeze-dried bone allograft (DFDBA) has been histologically proven to be the material of choice for regeneration. However, platelet-rich fibrin (PRF) has been said to have several properties that aid in healing and regeneration. Hence, this study focuses on the regenerative capacity of PRF when compared with DFDBA.

MATERIALS AND METHODS

A total of 40 sites with intrabony defects were selected and were assigned to the test group (open flap debridement [OFD] and PRF, n = 20) and the control group (OFD + DFDBA, n = 20). At the test sites, two PRF plugs were placed in the intrabony defect after debridement of the site and flap was sutured in place. The parameters measured were probing depth (PD), relative attachment level (RAL), and gingival marginal level (GML). These parameters were measured just before surgery (baseline) and at 6 months postsurgery. The changes in PD, RAL, and GML were analyzed at baseline and postsurgically after 6 months in each group with paired t-test and between the two groups with unpaired t-test.

RESULTS

The mean reduction in PD after 6 months in the test PRF group is 3.67 ± 1.48 mm where in control DFDBA group is 3.70 ± 1.78 mm. Gain in RAL in the test PRF group is 2.97 ± 1.42 mm where in control DFDBA group, it is 2.97 ± 1.54 mm. Gingival margin migrated apically in the test PRF group by 0.43 ± 1.31 mm where in control DFDBA group by 0.72 ± 2.3 mm. It was seen that the differences in terms of PD (P = 0.96), RAL (P = 1.00) and GML (P = 0.62) were not significant.

CONCLUSION

Platelet-rich fibrin has shown significant results after 6 months, which is comparable to DFDBA for periodontal regeneration in terms of clinical parameters. Hence, it can be used in the treatment of intrabony defects.

Interdisciplinary management of an isolated intrabony defect

The treatment of intrabony defects is a real challenge in molar teeth as it is chronic, slowly progressing disease which needs timely intervention. Periodontal inflammation associated with intrabony defect is not a separate entity as it secondarily affects the pulp causing retrograde pulpitis. However, treatment of these lesions will be complicated due to extensive bone loss. The tooth was endodontically treated followed by periodontal surgery to eliminate the deep periodontal pocket and promote bone fill in osseous defect. PepGen P-15 composited with platelet rich plasma was utilized for enhancing bone formation. The combination of these graft materials provides synergistic effect on bone regeneration.

Evolution of Barrier Membranes in Periodontal Regeneration-"Are the third Generation Membranes really here?"

In the last decades, Guide Tissue Regeneration (GTR) technique has been applied for the treatment of various periodontal defects such as intrabony defects, furcation involvements and localized gingival recession defects. From early days of using membranes with the simple aim of minimizing toxic response in the host, membranes have come a long way. Third generation membranes not only act as barriers but also as delivery devices to release specific agents. Many clinical trials have focused on using membranes as delivery devices for antibiotics and growth factors. In this article we take a brief look at the evolution of barrier membranes and future avenues with regard to third generation membranes.

Platelet rich fibrin - a novel acumen into regenerative endodontic therapy

Research into regenerative dentistry has added impetus onto the field of molecular biology. It can be documented as a prototype shift in the therapeutic armamentarium for dental disease. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. A new family of platelet concentrates called the platelet rich fibrin (PRF) has been recently used by several investigators and has shown application in diverse disciplines of dentistry. This paper is intended to add light on the various prospects of PRF and clinical insights to regenerative endodontic therapy.

Bioactive membranes for bone regeneration applications: effect of physical and biomolecular signals on mesenchymal stem cell behavior

This study focuses on the in vitro characterization of bioactive elastin-like recombinamer (ELR) membranes for bone regeneration applications. Four bioactive ELRs exhibiting epitopes designed to promote mesenchymal stem cell adhesion (RGDS), endothelial cell adhesion (REDV), mineralization (HAP), and both cell adhesion and mineralization (HAP-RGDS) were synthesized using standard recombinant protein techniques. The materials were then used to fabricate ELR membranes incorporating a variety of topographical micropatterns including channels, holes and posts. Primary rat mesenchymal stem cells (rMSCs) were cultured on the different membranes and the effects of biomolecular and physical signals on cell adhesion, morphology, proliferation, and differentiation were evaluated. All results were analyzed using a custom-made MATLAB program for high throughput image analysis. Effects on cell morphology were mostly dependent on surface topography, while cell proliferation and cell differentiation were largely dependent on the biomolecular signaling from the ELR membranes. In particular, osteogenic differentiation (evaluated by staining for the osteoblastic marker osterix) was significantly enhanced on cells cultured on HAP membranes. Remarkably, cells growing on membranes containing the HAP sequence in non-osteogenic differentiation media exhibited significant up-regulation of the osteogenic marker as early as day 5, while those growing on fibronectin-coated glass in osteogenic differentiation media did not. These results are part of our ongoing effort to develop an optimized molecularly designed periosteal graft.

Effects of different scaffolds on rat adipose tissue derived stroma cells

BACKGROUND

Adipose tissue derived stroma cells (ASC's) offer for many advantages for tissue engineering strategies over mesenchymal stroma cells from other sources and ideal carrier materials have to be identified for them. The aim of this study was to demonstrate and to compare the effects of three clinically established biomaterials on proliferation and metabolic activity of rat ASC's in vitro.

MATERIALS AND METHODS

Rat adipose tissue derived stroma cells (ASC's) were isolated and differentiated into distinct lineages proved by lineage specific staining and gene expression analysis (RT-PCR). The biomaterials Bio-Gide(®), Tutodent(®) Membrane and Belotero(®) Soft were tested with rat ASC's for their biocompatibility using scanning electron microscopy (SEM), cell vitality staining, cytotoxicity and proliferation tests (LDH, MTT, BrdU, WST-1).

RESULTS

The collagen membrane Bio-Gide(®) resulted in a significantly higher viability and proliferation (WST-1, BrdU) compared to Tutodent(®) Membrane. No significant difference was determined in the LDH and MTT test. The hyaluronic acid gel Belotero(®) Soft showed no cytotoxicity (LDH, FDA/PI) and had no negative effects on metabolic activity (WST-1, MTT) or cell proliferation (BrdU) of ASC's.

CONCLUSION

Our results indicate Bio-Gide(®) and Belotero(®) Soft as preferable carrier materials for ASC's. For the further establishment of ASC's-based treatment strategies, in vivo investigations on the tissue regeneration potential of these cell-biomaterial scaffolds should follow.

Sinus Augmentation With Platelet-Rich Fibrin in Combination With Bovine Bone Graft Versus Bovine Bone Graft in Combination With Collagen Membrane

The purpose of this study was to compare the efficacy between the use of bovine bone graft material and platelet-rich fibrin (PRF) mixture (test group) and bovine bone graft material and collagen membrane combination (control group) in 2-stage maxillary sinus augmentation. According to specific inclusion/exclusion criteria, patients treated between 2008 and 2012 were selected. Panoramic radiographs were used for radiologic assessments. To evaluate the relationship between sinus-graft height and each implant, the bone level (BL) was divided by implant length (IL). To evaluate the change in the height of grafted sinus, the grafted sinus floor above the lowest part of the original sinus height (GSH) was divided by the original sinus height (OSH). Samples taken during implant surgery were used for histologic and histomorphometric analyses. Twenty-five patients, 32 augmentation surgeries, and 66 one-stage implants were included in the study. No implant loss or complication was observed in either group. There were no statistical differences according to new bone formation (P = .61) and biomaterial remnant (P = .87). During the evaluation period, the test group showed statistically less change in the BL/IL ratio (P = .022). The difference of GSH/OSH ratio was found to be insignificant between groups (P = .093). It was observed that the grafted sinus covering the implant apex and sinus floor was above the original sinus height in both groups. It may be concluded from this study that both combinations can be successfully used for sinus augmentation. Further studies evaluating different graft materials and PRF combinations in the early phases of healing would be beneficial.

Role of Platelet rich fibrin in wound healing: A critical review

AIM

The aim is to review and discuss the strategies available for use of platelet rich fibrin as healing aid in dentistry.

BACKGROUND

Platelet rich fibrin (PRF) is a fibrin matrix in which platelet cytokines, growth factors, and cells are trapped and may be released after a certain time and that can serve as a resorbable membrane. Choukroun and his associates were amongst the pioneers for using PRF protocol in oral and maxillofacial surgery to improve bone healing in implant dentistry. Autologous PRF is considered to be a healing biomaterial, and presently, studies have shown its application in various disciplines of dentistry.

MATERIALS AND METHODS

By using specific keywords, electronic search of scientific papers was carried out on the entire PubMed database with custom range of 5 years. The electronic search yielded 302 papers; based on inclusion and exclusion criteria which were specifically predetermined, 72 papers were identified as suitable to the inclusion criteria and the remaining 230 papers were excluded. After adding three more selected papers through hand search, full text of all the articles retrieved and review was done. By pooling the extracted data from selected papers, the reviewed data was synthesized.

CONCLUSION

Recently by showing good promising results with use of the PRF, it has proved to have a good prospect for its use as healing aid in various aspects of the dentistry.

Platelet-Rich Fibrin as a Biofuel for Tissue Regeneration

Wound healing is a staged process which involves the activity of leukocytes and platelets. For this process to work efficiently, the platelets play a vital role. The growth factors present in platelets are important to guide the regenerating cells to the area of healing. Platelet-rich-fibrin (PRF) is one such material that holds on to these growth factors enmeshed in the fibrin network resulting in their sustained release over a period of time that can accelerate the wound healing process. With this knowledge, research has been carried out for a past few years for the clinical application of PRF. Various platelet concentrates have been studied including the platelet-rich-plasma (PRP). However, the short duration of cytokine release and its poor mechanical properties have resulted in the search of a new material with adequate properties for clinical application and ease of preparation. PRF has found a place in the regenerative field owing to its advantages over PRP. This review focuses on the properties and various applications of PRF in the clinical practice.

Combination of platelet rich fibrin, hydroxyapatite and PRF membrane in the management of large inflammatory periapical lesion

Periapical inflammatory lesion is the local response of bone around the apex of tooth that develops after the necrosis of the pulp tissue or extensive periodontal disease. The final outcome of the nature of wound healing after endodontic surgery can be repair or regeneration depending on the nature of the wound; the availability of progenitor cells; signaling molecules; and micro-environmental cues such as adhesion molecules, extracellular matrix, and associated non-collagenous protein molecules. The purpose of this case report is to add knowledge to the existing literature about the combined use of graft material [platelet rich fibrin (PRF) and hydroxyapatite (HA)] and barrier membrane in the treatment of large periapical lesion. A periapical endodontic surgery was performed on a 45 year old male patient with a swelling in the upper front teeth region and a large bony defect radiologically. The surgical defect was filled with a combination of PRF and HA bone graft crystals. The defect was covered by PRF membrane and sutured. Clinical examination revealed uneventful wound healing. Radiologically the HA crystals have been completely replaced by new bone at the end of 2 years. On the basis of the results obtained in our case report, we hypothesize that the use of PRF in conjunction with HA crystals might have accelerated the resorption of the graft crystals and would have induced the rapid rate of bone formation.

Elucidating multiscale periosteal mechanobiology: a key to unlocking the smart properties and regenerative capacity of the periosteum?

The periosteum, a thin, fibrous tissue layer covering most bones, resides in a dynamic, mechanically loaded environment. The periosteum also provides a niche for mesenchymal stem cells. The mechanics of periosteum vary greatly between species and anatomical locations, indicating the specialized role of periosteum as bone's bounding membrane. Furthermore, periosteum exhibits stress-state-dependent mechanical and material properties, hallmarks of a smart material. This review discusses what is known about the multiscale mechanical and material properties of the periosteum as well as their potential effect on the mechanosensitive progenitor cells within the tissue. Furthermore, this review addresses open questions and barriers to understanding periosteum's multiscale structure-function relationships. Knowledge of the smart material properties of the periosteum will maximize the translation of periosteum and substitute periosteum to regenerative medicine, facilitate the development of biomimetic tissue-engineered periosteum for use in instances where the native periosteum is lacking or damaged, and provide inspiration for a new class of smart, advanced materials.

Elucidating multiscale periosteal mechanobiology: a key to unlocking the smart properties and regenerative capacity of the periosteum?

The periosteum, a thin, fibrous tissue layer covering most bones, resides in a dynamic, mechanically loaded environment. The periosteum also provides a niche for mesenchymal stem cells. The mechanics of periosteum vary greatly between species and anatomical locations, indicating the specialized role of periosteum as bone's bounding membrane. Furthermore, periosteum exhibits stress-state-dependent mechanical and material properties, hallmarks of a smart material. This review discusses what is known about the multiscale mechanical and material properties of the periosteum as well as their potential effect on the mechanosensitive progenitor cells within the tissue. Furthermore, this review addresses open questions and barriers to understanding periosteum's multiscale structure-function relationships. Knowledge of the smart material properties of the periosteum will maximize the translation of periosteum and substitute periosteum to regenerative medicine, facilitate the development of biomimetic tissue-engineered periosteum for use in instances where the native periosteum is lacking or damaged, and provide inspiration for a new class of smart, advanced materials.

Comparative evaluation of autologous platelet-rich fibrin and platelet-rich plasma in the treatment of mandibular degree II furcation defects: a randomized controlled clinical trial

BACKGROUND

The treatment of molar furcation defects remains a considerable challenge in clinical practice. The identification of clinical measurements influential to treatment outcomes is critical to optimize the results of surgical periodontal therapy. The present study aimed to explore the clinical and radiographical effectiveness of autologous platelet-rich fibrin (PRF) and autologous platelet-rich plasma (PRP) in the treatment of mandibular degree II furcation defects in subjects with chronic periodontitis.

MATERIAL AND METHODS

Seventy-two mandibular degree II furcation defects were treated with either autologous PRF with open flap debridement (OFD; 24 defects) or autologous PRP with OFD (25), or OFD alone (23). Clinical and radiological parameters such as probing depth, relative vertical clinical attachment level and horizontal clinical attachment level along with gingival marginal level were recorded at baseline and 9 mo postoperatively.

RESULTS

All clinical and radiographic parameters showed statistically significant improvement at both the test sites (PRF with OFD and PRP with OFD) compared to those with OFD alone. Relative vertical clinical attachment level gain was also greater in PRF (2.87 ± 0.85 mm) and PRP (2.71 ± 1.04 mm) sites as compared to control site (1.37 ± 0.58 mm), and relative horizontal clinical attachment level gain was statistically significantly greater in both PRF and PRP than in the control group.

CONCLUSIONS

The use of autologous PRF or PRP were both effective in the treatment of furcation defects with uneventful healing of sites.

Comparison of two different absorbable membranes for the coverage of lateral osteotomy sites in maxillary sinus augmentation: a preliminary study

INTRODUCTION

Barrier membranes, both absorbable and non-absorbable, have been used in sinus augmentation for many years. Some years ago, a new autologous blood substrate called Platelet-Rich-Fibrin (PRF) was introduced, and to date, the supporting effect on bone regeneration has been controversial. This study aimed to evaluate the effect of PRF on bone regeneration when used as a barrier membrane at the lateral osteotomy site in sinus augmentation.

MATERIAL AND METHODS

Twelve sinuses from six patients requiring bilateral sinus floor augmentation were treated with a two-stage surgical technique using sinus augmentation and implant placement after 5 months. The sinuses were grafted with autologous bone and bone-substitute material (Bio-Oss(®)) mixed in a 1:1 ratio and were covered in a randomized split-mouth design with a PRF or a conventional collagen membrane (Bio-Gide(®)), respectively. Five months later threaded titanium dental implants were inserted and bone specimens harvested with a trephine burr were evaluated histomorphometrically.

RESULTS

Bone quality seemed to be equal at both sites of the grafted sinuses. Mean vital bone formation after 5 months was 17.0% and 17.2%, for the PRF and collagen sites, respectively. The mean of residual bone-substitute was 15.9% and 17.3% for PRF and collagen, respectively. No local complications, such as dehiscences or membrane exposures, were detected at either site in any of the treated patients. After 12 months all implants reached primary stability in the augmented maxillary sinus floor without any peri-implant tissue inflammation.

CONCLUSIONS

Within the limits of the study the coverage of the lateral sinus window with two different absorbable membranes has been shown to result in a similar amount of vital bone formation and residual bone-substitute.

Platelet rich fibrin: a new paradigm in periodontal regeneration

Among the great challenges facing clinical research is the development of bioactive surgical additives regulating inflammation and increasing healing. Although the use of fibrin adhesives and platelet-rich plasma (PRP) is well documented, they have their own limitations. Hence, reconstructive dental surgeons are looking for an "edge" that jump starts the healing process to maximize predictability as well as the volume of regenerated bone. Overcoming the restrictions related to the reimplantation of blood-derived products, a new family of platelet concentrate, which is neither a fibrin glue nor a classical platelet concentrate, was developed in France. This second generation platelet concentrate called platelet-rich fibrin (PRF), has been widely used to accelerate soft and hard tissue healing. Its advantages over the better known PRP include ease of preparation/application, minimal expense, and lack of biochemical modification (no bovine thrombin or anticoagulant is required). This article serves as an introduction to the PRF "concept" and its potential clinical applications with emphasis on periodontal regeneration.

Platelet rich fibrin: a novel approach for osseous regeneration

 : To evaluate the efficacy of autologous platelet rich fibrin in soft tissue healing and bone regeneration in mandibular third molar extraction sockets.

METHOD

The study was conducted in 20 patients visiting in outpatient department of Oral and Maxillofacial Surgery, requiring extraction of bilateral mandibular third molar, following extraction platelet rich fibrin (PRF) was placed in one extraction sockets, the other socket was studied as the control sites with no PRF. The patient were assessed for post operative pain, soft tissue healing and trabecular pattern in healing bone. Radiological assessment of the extraction site was done for period of 3 months to evaluate the change in bone density.

RESULTS

Pain was less in study side compare to control site soft tissue was healing was better in study site. Evaluation of trabecular bone formation started earlier in PRF site compare to control site. The evaluation of bone density by radiological assessment showed the grey level value calculated after 3 months at the PRF site well comparatively higher than the average baseline value of the bone density at the extraction site in control site.

CONCLUSION

The study showed that autologous PRF is biocompatible and has significantly improved soft tissue healing. Bone regeneration and increase in bone density in extraction sockets. However, a more elaborate study with a large number of clinical cases is essential to be more conclusive regarding its efficacy.

Comparative evaluation of autologous platelet-rich fibrin and platelet-rich plasma in the treatment of 3-wall intrabony defects in chronic periodontitis: a randomized controlled clinical trial

BACKGROUND

The topical use of platelet concentrates is recent, and its efficiency remains controversial. The present study aims to explore the clinical and radiographic effectiveness of autologous platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) in the treatment of intrabony defects in patients with chronic periodontitis.

METHODS

Ninety intrabony defects were treated with either autologous PRF with open-flap debridement or autologous PRP with open-flap debridement or open-flap debridement alone. Clinical and radiologic parameters, such as probing depth (PD), clinical attachment level (CAL), intrabony defect depth, and percentage defect fill, were recorded at baseline and 9 months postoperatively.

RESULTS

Mean PD reduction and CAL gain were greater in PRF (3.77 ± 1.19 and 3.17 ± 1.29 mm) and PRP (3.77 ± 1.07 and 2.93 ± 1.08 mm) groups than the control group (2.97 ± 0.93 and 2.83 ± 0.91 mm). Furthermore, significantly greater percentage of mean bone fill was found in the PRF (55.41% ± 11.39%) and PRP (56.85% ± 14.01%) groups compared with the control (1.56% ± 15.12%) group.

CONCLUSIONS

Within the limit of the present study, there was similar PD reduction, CAL gain, and bone fill at sites treated with PRF or PRP with conventional open-flap debridement. Because PRF is less time consuming and less technique sensitive, it may seem a better treatment option than PRP. However, long-term, multicenter randomized, controlled clinical trials will be required to know their clinical and radiographic effects on bone regeneration.

Comparison of platelet rich fibrin and collagen as osteoblast-seeded scaffolds for bone tissue engineering applications

OBJECTIVES

The loss of jaw bone caused by different kinds of pathologies leads to dysfunction and reduced quality of life in affected patients. Thus, the pivotal goal in bone tissue engineering is to reconstruct these defects. The essential precondition for new tissue generation is an extracellular matrix which acts as a scaffold so that cells can migrate, differentiate, and proliferate. Fibrin, a biopolymer responsible for blood clot formation, has been shown to be suitable for tissue engineering applications. The aim of the present study is a comparison of platelet rich fibrin (PRF) with the commonly used collagen membrane BioGide(®) as a scaffold for human osteoblast cell seeding for bone tissue engineering.

MATERIAL AND METHODS

Human osteoblasts were cultured with eluates from PRF (n = 7) and BioGide(®) (n = 8) membranes incubated in serum-free cell culture medium. Vitality of these cells was assessed by fluorescein diacetate and propidium iodide staining, biocompatibility with the lactate dehydrogenase test and proliferation levels with the MTT ([3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide]), and BrdU (5-bromo-2-deoxyuridine) tests. In addition, human osteoblasts were seeded on both membrane systems and cell growth was compared by the water soluble tetrazolium (WST-1) (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate) test and scanning electron microscopy (SEM). Osteoblastic differentiation was assessed by alkaline phosphatase activity measured by ELISA in the supernatant of osteoblasts cultivated on PRF membranes (n = 10), PRF clots (n = 10), and BioGide(®) membranes (n = 10).

RESULTS

Lactate dehydrogenase test values were higher for PRF compared to BioGide(®) . The BrdU test showed superior cell growth after cultivation in eluate from PRF than in eluate from BioGide(®) . The WST-1 assay demonstrated superior cell proliferation on PRF than on BioGide(®) . SEM revealed osteoblast colonization of both membranes. Cultivation of osteoblasts on PRF membranes and PRF clots showed significantly higher alkaline phosphatase activity than on BioGide(®) membranes.

CONCLUSION

Metabolic activity and proliferation of human osteoblast cells in vitro were supported to a significant higher extent by eluates from PRF membranes. Both membranes are suitable as scaffolds for cultivation of human osteoblast cells in vitro; proliferation was significant higher on PRF membranes and on PRF clot than on BioGide(®) membranes.

[Engineering a bone free flap for maxillofacial reconstruction: technical restrictions]

Vascularisation is a key for success in bone tissue engineering. Creating a functional vascular network is an important concern so as to ensure vitality in regenerated tissues. Many strategies were developed to achieve this goal. One of these is cellular growth technique by perfusion bioreactor chamber. These new technical requirements came along with improved media and chamber receptacles: bioreactors (chapter 2). Some bone tissue engineering processes already have clinical applications but for volumes limited by the lack of vascularisation. Resorbable or non-resorbable membranes are an example. They are used separately or in association with bone grafts and they protect the graft during the revascularization process. Potentiated osseous regeneration uses molecular or cellular adjuvants (BMPs and autologous stem cells) to improve osseous healing. Significant improvements were made: integration of specific sequences, which may guide and enhance cells differentiation in scaffold; nano- or micro-patterned cell containing scaffolds. Finally, some authors consider the patient body as an ideal bioreactor to induce vascularisation in large volumes of grafted tissues. "Endocultivation", i.e., cellular culture inside the human body was proven to be feasible and safe. The properties of regenerated bone in the long run remain to be assessed. The objective to reach remains the engineering of an "in vitro" osseous free flap without morbidity.

Simultaneous sinus-lift and implantation using microthreaded implants and leukocyte- and platelet-rich fibrin as sole grafting material: a six-year experience

PURPOSE

To assess the relevance of simultaneous sinus-lift and implantation with leukocyte- and platelet-rich fibrin (L-PRF, Choukroun's technique) as sole subsinus filling material.

MATERIALS

Twenty-three lateral sinus elevations (SA4 sinus) were performed on 20 patients with simultaneous implant placement. Seven patients were treated with 19 Astra implants (AstraTech, Mölndal, Sweden) and 13 patients with 33 Intra-Lock implants (Intra-Lock Ossean, Boca Raton, FL). L-PRF membranes were used to cover the Schneiderian membrane, the implant tips served as "tent pegs" for the L-PRF-patched sinus membranes, and the subsinus cavity was finally filled with L-PRF clots. Clinical and radiographic follow-up was performed just after implant placement, after 6 months, 1 year and each following year.

RESULTS

Six months after surgery, all implants were clinically stable during abutment tightening. The maximum follow-up was 6 years, and all patients were followed up for a minimum of 2 years. No implant was lost during this 6-year experience, and the vertical bone gain was always substantial, between 8.5 and 12 mm bone gain (10.4 ± 1.2). The final level of the new sinus floor was always in continuation with the implant apical end, and the periimplant crestal bone height was stable.

CONCLUSION

The use of L-PRF as sole filling material during simultaneous sinus-lift and implantation seems to be a reliable surgical option promoting natural bone regeneration.

Treatment of 3-wall intrabony defects in patients with chronic periodontitis with autologous platelet-rich fibrin: a randomized controlled clinical trial

BACKGROUND

Platelet-rich fibrin (PRF) is considered a second-generation platelet concentrate that is widely used in osseous regeneration. The present study aims to explore the clinical and radiographic effectiveness of autologous PRF in the treatment of intrabony defects in patients with chronic periodontitis.

METHODS

Fifty-six intrabony defects were treated with either autologous PRF with open-flap debridement or open-flap debridement alone. Clinical parameters such as the probing depth (PD) and periodontal attachment level (PAL) were recorded at baseline and 9 months postoperatively. The defect fill at baseline and 9 months was calculated on standardized radiographs by using image-analysis software.

RESULTS

The mean PD reduction was greater in the test group (4.55 ± 1.87 mm) than in the control group (3.21 ± 1.64 mm), whereas the mean PAL gain was also greater in the test group (3.31 ± 1.76) compared to the control group (2.77 ± 1.44 mm). Furthermore, a significantly greater percentage of mean bone fill was found in the test group (48.26% ± 5.72%) compared to the control group (1.80% ± 1.56%).

CONCLUSIONS

Within the limits of the present study, there was greater PD reduction, PAL gain, and bone fill at sites treated with PRF with conventional open-flap debridement compared to conventional open-flap debridement alone. However, a long-term, multicentered randomized controlled clinical trial is required to know the clinical and radiographic effects of PRF on bone regeneration.