Platelet-rich Fibrin Preparation Research Articles

Platelet-rich fibrin: A review of its role as a new treatment in androgenetic alopecia.

Androgenetic alopecia (AGA) is a major cause of hair loss resulting from a complex interplay between various genes and hormones with the result being follicular miniaturization and altered hair cycle dynamics. Platelet-rich plasma (PRP) has a well-established role as adjunctive therapy in AGA but there are many limitations of it. In an attempt to overcome the shortcomings of PRP, liquid platelet-rich fibrin (PRF) was developed. This article critically reviews the protocol for the preparation and clinical outcomes of PRF. The articles published so far in the English language regarding the preparation and clinical outcomes of PRF were reviewed. Among five studies analyzing various centrifugation speeds and centrifugation times, three of the studies favored low-speed centrifugation, whereas two studies did not support this methodology. A horizontal centrifuge may be preferred over a fixed-angle centrifuge for PRF. Five clinical studies on the use of PRF showed a significant effect on AGA. At present, there is no consensus regarding the preparation of PRF. Most studies used fixed-angle centrifugation favored low centrifuge speed and less centrifugation time. Larger studies are needed to determine the optimal centrifugation force and time. A horizontal centrifuge may be preferred over a fixed-angle centrifuge due to the higher yield of platelets, and lesser shear trauma to the cells. In addition, larger, well-designed studies are needed to confirm the benefits of PRF over PRP.

Industrial Mass Production of Platelet Dry Powder

The goal of this paper is to examine the use of pig blood in the industrial mass production of platelet dry powder and to transform platelet dry powder into a low-cost and mass-produced material. Platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) contain multiple types of growth factors (GFs) and can be widely used in medical applications. However, neither can be mass-produced, due to the complexity of the PRP preparation process and the lack of anticoagulants in the PRF preparation process, increasing the risk of coagulation during mass production. Another obstacle is the insufficient supply of autologous PRP and autologous PRF. In this study, platelet dry powder was mass-produced from pig blood through the indirect addition of calcium chloride solution. Furthermore, the results showed that different concentrations and percentages of calcium chloride solution had significant effects on concentrations of TGF-β1 and PDGF-BB in the platelet dry powder. The platelet dry powder mass-produced from pig blood demonstrated high concentrations of GFs and long-term shelf stability, increasing the supply to industries that use it in product development.

Sustainability and Release Pattern of Growth Factors from Bone Grafts Prepared with Platelet-Rich Fibrin.

Platelet-rich fibrin (PRF) is used to prepare "sticky bone" by combining it with bone graft material. The present study investigated the ability of different bone grafts to absorb growth factors from the PRF and release them over time. Human blood was collected from 10 healthy volunteers for liquid PRF preparation. Bovine bone, allograft (mineralized and demineralized), and synthetic bone were each mixed with the PRF to prepare a sticky bone. All sticky bone samples were incubated for up to 4 days. The absorption and release pattern kinetics of two selective growth factors within the PRF-platelet-derived growth factor (PDGF) and bone morphogenetic protein-2 (BMP-2)-were quantified with immunofluorescence staining and enzyme-linked immunoassay (ELISA) testing. All bone graft materials adsorbed the examined growth factors from the PRF. β-TCP showed the highest adsorption levels, followed by the xenograft, and the allografts showed the lowest adsorption levels. Furthermore, PDGF showed a fast-release pattern from the grafts, whereas BMP-2 was released at a later stage. Similar to the adsorption pattern, the β-TCP and xenograft were better able to sustain the release of the PRF growth factors from the graft than the allografts. The adsorption of PDGF and BMP-2 differ between graft materials, with superior results for β-TCP, followed by xenograft, then allograft materials.

Metformin-suppressed platelet's function in vitro: Possible relation to delayed or failure of platelet-rich fibrin preparation

Platelet-rich fibrin (PRF) is a popular autologous blood-derived biomaterial that is used in regenerative therapy. Owing to its simple preparation without additional factors, the PRF quality directly reflects the characteristics of individual blood samples. Antiplatelet or anticoagulant drugs can hamper the successful preparation of PRF. We recently observed similar phenomena in metformin-taking type-2 diabetics (T2DM). Thus, we hypothesized that metformin interferes with platelet function, thereby suppressing coagulation. For practical reasons, leukocyte- and platelet-rich plasma was prepared from healthy male donors (n = 9–15, age: 26–80 years) and treated with metformin (1–10 mM) for 24–72 h. Intrinsic and extrinsic coagulation activities were evaluated using prothrombin time (PT) and activated partial thromboplastin time (ATPP). Platelet adhesion and aggregation assays were performed using ADP stimulation. Among the parameters tested, APTT was the most sensitive and was significantly prolonged in the concentration range of 1–10 mM in a time- and concentration-dependent manner. Although obtained from healthy platelets and relatively higher concentrations of metformin, these findings suggest that metformin may induce further dysfunction of platelets to suppress intrinsic coagulation activity in T2DM patients, leading to failure of PRF preparation. This phenomenon may not have a severe impact on clinical diabetology or hematology. However, clinicians using PRF are recommended to be more sensitive to such information to avoid unexpected events in clinical settings.

Platelet-rich fibrin: A promising regenerative material

Periodontal regeneration is a process involving biological events such as cell adhesion, migration, proliferation, and differentiation in an orchestrated sequence. It is well known that platelets play a key role in hemostasis and the wound healing process. Platelets were introduced as regenerative potential. Choukroun et al. (2001) first described platelet-rich fibrin (PRF). It is the second generation of platelet concentration. It consists of a natural fibrin matrix. It is autogenous fibrin made up of the patient’s blood free from anticoagulants. It is three-dimensional architecture consisting of the specific composition of leukocyte and platelet-rich fibrin biomaterials. Various technique has been used in the preparation of PRF but Choukroun’s PRF technique is the most common and easy technique developed in France. The patient’s blood was taken at around 5 ml which is collected in each of the two sterile vacutainer tubes with a 6 ml capacity without anticoagulant and centrifugation. PRF is used in various fields such as endodontics, oral and maxillofacial surgery, periodontics, and tissue engineering. It is more economical and easy preparation than other grafts. PRF should be handled properly before it shrinks and gets dehydrated. It is the most successful periodontal regenerative material.

Blood Clots versus PRF: Activating TGF-β Signaling and Inhibiting Inflammation In Vitro.

The preparation of platelet-rich fibrin (PRF) requires blood centrifugation to separate the yellow plasma from the red erythrocyte fraction. PRF membranes prepared from coagulated yellow plasma are then transferred to the defect sites to support tissue regeneration. During natural wound healing, however, it is the unfractionated blood clot (UBC) that fills the defect site. It is unclear whether centrifugation is necessary to prepare a blood-derived matrix that supports tissue regeneration. The aim of the present study was to compare lysates prepared from PRF and UBC based on bioassays and degradation of the respective membranes. We report here that lysates prepared from PRF and UBC membranes similarly activate TGF-β signaling, as indicated by the expression of interleukin 11 (IL-11), NADPH oxidase 4 (NOX-4) and proteoglycan 4 (PRG4) in gingival fibroblasts. Consistently, PRF and UBC lysates stimulated the phosphorylation and nuclear translocation of Smad3 in gingival fibroblasts. We further observed that PRF and UBC lysates have comparable anti-inflammatory activity, as shown by the reduction in lipopolysaccharide (LPS)-induced IL-6, inducible nitric oxidase synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in RAW264.7 cells. Moreover, inflammation induced by Poly (1:C) HMW and FSL-1, which are agonists of Toll-like receptor (TLR) 3 and 2/6, respectively, was reduced by both PRF and UBC. PRF and UBC lysates reduced the nuclear translocation of p65 in LPS-induced RAW264.7 cells. In contrast to the similar activity observed in the bioassays, UBC membranes lack the structural integrity of PRF membranes, as indicated by the rapid and spontaneous disintegration of UBC membranes. We show here that the lysates prepared from PRF and UBC possess robust TGF-β and anti-inflammatory activity. However, visual inspection of the PRF and UBC membranes confirmed the negative impact of erythrocytes on the structural integrity of membranes prepared from whole blood. The data from the present study suggest that although both UBC and PRF have potent TGF-β and anti-inflammatory activity, UBC does not have the strength properties required to be used clinically to prepare applicable membranes. Thus, centrifugation is necessary to generate durable and clinically applicable blood-derived membranes.

Responses of promyelocytic leukemia HL60 cells as an inflammatory cell lineage model to silica microparticles used to coat blood collection tubes

BackgroundThe preparation of platelet-rich fibrin (PRF) requires glass blood collection tubes, and thus, the shortage or unavailability of such tubes has driven clinicians to search for suitable substitutes, such as silica-coated plastic tubes. However, we have previously demonstrated the cytotoxicity of silica microparticles (MPs) used in plastic tubes to cultured human periosteal cells. To further establish the effects of silica MPs on inflammation, we examined silica MP-induced changes in a human promyelocytic cell model in vitro.MethodsHuman promyelocytic HL60 cells were used either without chemical induction or after differentiation induced using phorbol myristate acetate (PMA) or dimethyl sulfoxide. HL60 cells, osteoblastic MG63, and Balb/c mouse cells were treated with silica MPs, and their surface ultrastructure and numbers were examined using a scanning electron microscope and an automated cell counter, respectively. Differentiation markers, such as acid phosphatase, non-specific esterase, and CD11b, were visualized by cytochemical and immunofluorescent staining, and superoxide dismutase (SOD) activity was quantified.ResultsRegardless of SOD activity, silica cytotoxicity was observed in MG63 and Balb/c cells. At sub-toxic doses, silica MPs slightly or moderately upregulated the differentiation markers of the control, PMA-induced monocytic, and dimethyl sulfoxide-induced granulocytic HL60 cells. Although SOD activity was the highest (P < 0.05) in PMA-induced cells, a silica-induced reduction in cell adhesion was observed only in those cells (P < 0.05).ConclusionsSilica MP contamination of PRF preparations can potentially exacerbate inflammation at implantation sites. Consequently, unless biomedical advantages can be identified, silica-coated plastic blood collection tubes should not be routinely used for PRF preparations.

The effect of resting and compression time post-centrifugation on the characteristics of platelet rich fibrin (PRF) membranes.

To evaluate the effect of resting and compression time after centrifugation on the physical properties of platelet rich fibrin (PRF) membranes, and to provide optimal guidance regarding the clinical preparation of PRF. A total of 12 volunteers enrolled in this study divided into 2 groups equally. For each volunteer, 6 tubes of 10mL venous whole blood was drawn. To evaluate the influence of resting time after centrifugation, PRF clots were taken out 0, 1, 3, 5, 7, and 10min from tubes following centrifugation, and then the weight, size, maximum stress, and maximum strain of each group were measured. To evaluate the influence of compression time on the preparation of PRF membranes, the weight ratio of PRF membranes to PRF clots was calculated by compression for 10s, 30s, 60s, 90s, 120s, and 180s, respectively. Scanning electron microscopy was performed to observe the cross-linking of the fibers within membranes, and the maximum stress and strain of PRF membranes were tested followed by stress-strain curve analysis. The weight and volume of PRF clots and PRF membranes increased in size and weight reached the top at 3min, followed by a decrease after 7-min resting. The maximum strain of the PRF membranes after 10min decreased significantly compared to the 3-min and 5-min groups. The maximum stress was found at 3min followed by a statistical decrease when resting time went on. Scanning electron microscopy demonstrated that the internal fibrous structure of the PRF membranes was looser when the compression time was less than 60s when comparing the 90-s group. The maximum stress of PRF membranes was shown using a wait period of 3min post-centrifugation followed by compression for 120s. The findings from the present study demonstrate that the time post-centrifugation of PRF membranes showed a maximum weight, volume, and mechanical properties after resting for 3-5min in the tube post-centrifugation followed by a compression time of 120s. Although research to date has focused primarily on centrifugation protocols, this study revealed for the first time that the resting time post-centrifugation greatly affected the mechanical properties of PRF. This study demonstrated that the resting and compression time after centrifugation influences the mechanical strength of PRF membranes, which might explain differences in PRF characteristics prepared by different clinicians that may provide a standard guide for preparation of PRF membranes.

Tranexamic acid integrated into platelet-rich fibrin produces a robust and resilient antihemorrhagic biological agent: a human cohort study

To investigate the incorporation of the antifibrinolytic agent tranexamic acid (TA) during platelet-rich fibrin (PRF) formation to produce a robust fibrin agent with procoagulation properties. Blood from healthy volunteers was collected. Into 3 tubes, TA was immediately added in 1-mL, 0.4-mL, and 0.2-mL volumes, and the fourth tube was without additions. After PRF preparation, the clots were weighed in their raw (clot) and membrane forms. PRF physical properties were analyzed using a universal testing system (Instron). Protein and TA levels in the PRF were analyzed using a bicinchoninic acid assay and a ferric chloride assay, respectively. The addition of TA to PRF led to a robust weight compared with sham control. PRF weight was greater in females in all tested groups. The addition of TA also led to greater resilience to tears, especially at 1-mL TA addition to the blood. Furthermore, TA addition led to a greater value of total protein within the PRF and entrapment of TA in the PRF. Addition of TA to a PRF preparation leads to robust PRF with greater protein levels and the amalgamation of TA into the PRF. Such an agent may enhance the beneficial properties of PRF and attribute procoagulation properties to it.

A Standardized g-Force Allows the Preparation of Similar Platelet-Rich Fibrin Qualities Regardless of Rotor Angle.

Platelet-rich fibrin (PRF) is an autologous blood concentrate that supports tissue regeneration. The effect of the centrifuge rotor angle in the fabrication of PRF is still not fully elucidated. The hypothesis of this study is: When applying the same g-force (relative centrifugal force [RCF]) and centrifugation time, PRF components and bioactivity are not modified using either a swing-out rotor or a fixed angle rotor. For this purpose, peripheral blood samples (from five donors) were used to gain solid (710 ×g, 8 min) and liquid (44 ×g, 8 min) PRF matrices using three different centrifuges (one fixed angle as a control and two different swing-out rotor centrifuges). The physical characteristics of the solid PRF were measured to evaluate the clot formation and cellular distribution. The liquid PRF was used to evaluate the cell number, bioactivity, and influence on primary human osteoblasts (pOBs) and primary human fibroblasts (pHFs) in vitro. Solid PRF clots were significantly larger in the group of fixed rotor centrifuges compared with either of the two evaluated swing-out rotor centrifuges. No differences were observed when evaluating the cellular distribution within the solid PRF. No statistically significant differences were documented in the cell's density in liquid PRF samples (platelets, lymphocytes, neutrophils, eosinophils, and basophils) among the differently gained PRF samples. No statistically significant differences were documented for the released growth factors (vascular endothelial growth factor, epidermal growth factor, and transforming growth factor beta 1) over 7 days. pOBs and pHFs viability after treatment with PRF conditioned media showed no statistically significant differences between the evaluated groups. However, the number of adherent cells treated with PRF obtained with the use of the fixed angle rotor was significantly higher when compared with those treated with PRF obtained by using the swing-out rotors. The presented results confirm that regardless of the centrifuge rotor used, the components and bioactivity of solid and liquid PRF matrices are modified by the applied RCF and centrifugation time. These findings are of great importance for highlighting the essential role of adapting the centrifugation protocols when using different centrifuges and to correctly report the used centrifugation protocols in scientific research to allow for reproducible results. Impact statement Platelet-rich fibrin (PRF) is prepared from autologous peripheral blood and is widely applied in research and clinical treatments. The centrifugation parameters used during the preparation of PRF directly influence its components and bioactivity. By using a standardized protocol, the present study demonstrated that adapting various centrifuges to a standardized relative centrifugal force and centrifugation protocol resulted in reproducible PRF matrices with similar bioactivity, regardless of the centrifuge rotor angle. These findings underline the necessity to carefully adapt and correctly report the used centrifuge and centrifugation protocols in scientific research to allow reproducible results.

Evaluation of L-platelet-rich fibrin in non- and post-COVID-19 patients and its role in periodontal regeneration – A microscopic analysis

Introduction: Platelet-rich fibrin (PRF) is a term for autologous platelet concentrates generated from the patient's own blood (PRF). PRF and its derivatives (L-PRF, A-PRF, i-PRF) have been used for delicate tissue restoration in a variety of dental procedures. The quantity of leucocytes and other growth factors in PRF of healthy and post-COVID-19 people differs, according to the literature, and these influence wound tissue healing. Materials and Methods: Thirty healthy volunteers and 30 post-COVID-19 volunteers (age range 24–60 years). For PRF preparation, a REMI PR-23 table centrifuge and a blood collection kit consisting of a 19G needle and 10 ml blood collection tubes were used. The analysis was performed by dividing the subject groups into three test groups (Group 1 – post-COVID-19, 0–30 days; Group 2 – post-COVID-19, 31–90 days; Group 3 – normal patients). Group 1, 2 and 3 consisted of 23, 7 and 30 patients, respectively. Results: The result was statistically significant between the normal and posted COVID-19 patient groups (P = 0.00). Not much statistical significance was found between post-COVID-19 patients from 0–30 days to 31–90 days (P = 0.370). Considering the limitations of the study, our findings imply that typical patients' PRF clots or membranes comprise the majority of platelets and half of the leucocytes present in the first blood collection. Conclusion: Within the fibrin network, platelet growth factors are stuck, but the PRF clot or membrane of the post-COVID-19 patients contains a reduced/negligible number of leucocytes. Thus, the growth factors which is released are also less. Therefore, usage of PRF in post-COVID-19 patients for periodontal regenerative therapies should be avoided, at least for the first 60 days, to replenish the reduced leucocyte count and growth factors in the blood.

The Uses and Application of Platelet Rich Fibrin in Clinical Practice

Platelet derivatives are commonly used in wound healing and tissue regeneration. Different procedures of platelet preparation may differentially affect growth factor release and cell growth. Preparation of platelet-rich fibrin (PRF) is accompanied by release of growth factors, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor b1 (TGFb1), and several cytokines. When compared with the standard procedure for platelet-rich plasma (PRP), PRF released 2-fold less PDGF, but 415-fold and 42-fold VEGF and TGF b1, respectively.

Non‐surgical management of oro‐antral communication using platelet‐rich fibrin: A review of the literature

AbstractOro‐antral communication (OAC) is an opening between the maxillary sinus and the oral cavity, which can provide a pathway to cause an infection of the maxillary sinus. Although surgical techniques propose many advantages, several drawbacks have been reported in the previous studies. Bioactive modifiers such as platelet‐rich fibrin (PRF) are widely being used in oral surgery. Various studies have been conducted for closure of OACs using PRF. Due to the heterogeneity of the techniques found, we opted for a literature review to highlight the variety of techniques discussed in the literature. A comprehensive search of the PubMed, Google Scholar and Cochrane databases was performed for published articles between 2014 and 2021. Keywords for OAC management and repair and inclusion criteria were used to screen articles for final review. Out of 195 articles found, 12 articles were included to the study. Eight studies performed simple direct application of PRF clots, 2 studies used PRF in combination with collagen membrane and in 2 studies the treatment plan was to use buccal advancement flap reinforced by PRF. There were several variations among approaches to the closure of OAC using PRF in terms of treatment planning, pre‐ and post‐operative medication and preparation of PRF. Despite the mentioned variations, review of recent studies showed that all of the cases experienced full epithelialisation of OAC. This technique, without manipulation of any additional flaps and auto‐grafts, has several advantages. However, further research, both experimental and clinical, is necessary to unravel the success rate of using PRF in the management of OACs.

Clinical Application of Platelet-Rich Fibrin in Dermatology

Platelet-rich fibrin (PRF) is a second-generation platelet concentrate obtained from autologous blood. PRF is composed of abundant platelets, leucocytes, and a high concentration of various growth factors and fibrinogen. The composition and three-dimensional structure of PRF enable it to effectively make cells migrate and proliferate, playing an important role in tissue repair. Furthermore, the easy preparation and low cost of PRF make it a good treatment option. Numerous articles have been published about the application of PRF in clinical practice, however, the application of PRF in dermatology has not been comprehensively reviewed. The objective of this review article was to discuss various applications of PRF in dermatology, including healing chronic wounds, treating androgenic alopecia, skin rejuvenation, autologous fat transplantation, and treating vitiligo. PRF is a promising dermatologic treatment, but lacks a standardized protocol regarding its methods of attainment and use, which needs more investigations.

Antibacterial and Antifungal Efficacy of Platelet-Rich Fibrin and Platelet-Rich Fibrin Matrix against Root Canal Microflora.

Background:Binding of such proteins with a developing fibrin mesh or to the extracellular matrix has the ability to create chemotactic gradients aiding the recruitment of stem cells, thereby, stimulating cell migration and differentiation this may promotes repair and regeneration. There is a unique concept in platelet concentrates called platelet-rich fibrin matrix (PRFM) which is processed using higher attraction without the utilization of bovine thrombin.Aim and Objectives:The aim of this study is to evaluate the antibacterial and antifungal effects of platelet-rich fibrin (PRF) and PRFM against root canal microflora.Materials and Methods:Blood samples were taken from 20 adults, age ranging from 20 to 40 years who were systemically healthy, nonsmokers with no symptoms of infection, or on antibiotics at least 3 months before experiments. The procedures and the protocols involved in the study were accepted by the Institutional Ethical Committee. Written informed consent was obtained from the donors and patients. Approximately 10 ml of blood was collected from each donor. 5 ml of blood was used for the preparation of PRF and 5 ml for PRFM.Results:The antifungal scores among the groups. The highest antifungal scores were seen in metapex followed by PRF and PRFM group. Kruskal–Wallis test was applied to check the statistical difference among the groups, and there was a statistically significant difference seen among the groups (P = 0.00). The antibacterial scores among the groups. The highest antibacterial scores were seen in Metapex followed by PRF group and PRFM group Kruskal–Wallis test was applied to check the statistical difference among the groups, and there was a statistically significant difference seen among the groups.Conclusion:PRF demonstrated antibacterial activity against passage isolates but had no antifungal efficacy. This antibacterial property may be a valuable adjunct when using PRF for regenerative procedures in endodontics. Both PRF and PRFM have to be analyzed for antimicrobial properties for extended duration and various other clinical strains with larger sample size.

English

Management of non-vital immature anterior permanent teeth in children remains a challenge in paediatric dentistry and endodontics. Once the tooth becomes non-vital, root development ceases, rendering the tooth weak, and unable to withstand physiological forces of mastication. This results in a high rate of root fracture with poor prognosis in the medium to long term. Despite being endodontically treated, over 50 % of such teeth will be lost in the first 10 years following trauma. Traditional endodontic treatment does not contribute to any quantitative or qualitative increase in root dimensions resulting in life-long oral disability. The advancement in the science of Endodontics - Regenerative Endodontics has revolutionized current treatment strategies in treating the immature non-vital permanent tooth which has overcome the drawbacks of traditional treatment approaches. This report provides an insight view on successful maturogenesis of immature non-vital permanent incisors by induction of intracanal bleeding along with complications endured during the process. Regenerative endodontics is defined as “biologically based procedures designed to replace damaged structures, including dentin and root structures, as well as cells of the pulp - dentin complex”.1 Continued root development and reestablishment of pulp - dentine complex can be achieved by these procedures. Two major concepts in the regenerative endodontics are guided tissue regeneration (GTR) and tissue engineering. The base of these procedures is stem cells which can differentiate into the desired tissue component, growth factors or other tissue - inducing mediators and scaffold.2 Regenerative endodontic procedure (REP) includes induction of intracanal bleeding, placement of platelet rich fibrin (PRF), and platelet rich plasma (PRP). The goals of these procedures were elimination of signs and symptoms, continued root development, apical healing, and positive response to vitality testing. But preparation of PRP and PRF requires withdrawal of blood and sight of syringe can add emotional stress to young patients. Revascularization may be defined as the invagination of undifferentiated periodontal cells from the apical region in immature teeth.3,4 The nature of tissue formed after revascularization is not certain and can be confirmed by histological evaluation. Presence of blood supply is reliable. Revascularization considers only one facet - nature of newly formed tissue thus making term revascularization inaccurate and thus many authors disagreed with this term.5

Platelet-rich fibrin: Basics of biological actions and protocol modifications.

Platelet-rich fibrin (PRF) represents second generation of platelet concentrates, which has gained increasing awareness in recent years for regenerative procedures. This biologic additive is completely autologous, easy to prepare, has minimal expense, and possesses prolonged growth factor release, together with several other advantages over traditionally prepared platelet concentrates. Since its introduction, various protocols for PRF preparation have been proposed with different amounts of growth factors and other biomolecules necessary for wound healing. However, reference data about potential effect of some PRF components on hard and soft tissue healing are still conflicting. The current article intends to clarify the relevant advances about physiological role of certain PRF components and to provide insight into the new developmental approach. Also, this review summarizes the evolution of platelet concentrates and biologic properties of different modifications of PRF procedure.

Impact of g force and timing on the characteristics of platelet-rich fibrin matrices

Recently, new centrifugation protocols for the preparation of platelet-rich fibrin (PRF) have been introduced in an attempt to further improve the beneficial impact of these 2nd generation platelet concentrate membranes. This in-vitro study aimed to compare the biological and physical characteristics of three types of PRF membranes using two different centrifuges with adapted relative centrifugal forces (RCF): leucocyte- and platelet-rich fibrin, advanced platelet-rich fibrin, and advanced platelet-rich fibrin+. Release of growth factors, macroscopic dimensions, cellular content and mechanical properties of the respective membranes, prepared from blood of the same individual were explored. Furthermore, the impact of timing (blood draw-centrifugation and centrifugation-membrane preparation) was assessed morphologically as well as by electron microscopy scanning. No statistically significant differences amongst the three PRF modifications could be observed, neither in their release of growth factors or the cellular content, nor in clot/membrane dimensions. The difference between both centrifuges were negligible when the same g-force was used. A lower g-force, however, reduced membrane tensile strength. Timing in the preparation process had a significant impact. Adaptation of RCF only had a minimal impact on the final characteristics of PRF membranes.

Blood Wettability of Different Dental Implant Surfaces after Different Pre-Treatments: Ultrasonic Instrumentation, Platelet-Rich Fibrin Coating, and Acid Etching. An In Vitro Study

Background: The blood wettability of titanium implant surfaces favors primary osseointegration and tissue healing in peri-implantitis. The current study aims to evaluate this property on the main different kinds of surfaces, brand new and after treatments. Methods: grade IV titanium disks were used, five machined, five laser-treated, five sandblasted. The experiment was on four steps. Between each step, specimens were sterilized. At the end of each step, a 4 µL blood drop was put on the samples, and contact angles were calculated. The steps consisted of—1: no treatment; 2: surface instrumentation with an ultrasonic titanium tip; 3: platelet-rich fibrin (PRF) coating and drying with sterile gauze; 4: etching with phosphoric acid, rinse and saline solution and air-drying. At the end of each phase, a blood drop was placed on the surfaces. Blood for PRF preparation and for calculation of contact angles was collected from a single source. Results: average wettability decreased after instrumentation, and increased after the PRF application to a superior level both to the first and second steps. The highest wettability was obtained after etching. This trend is statistically significant for machined and sandblasted surfaces. Conclusions: In the clinical environment, PRF and phosphoric acid used for conditioning exposed implant surfaces can be used for the healing of peri-implant tissues.

Platelet-Rich Fibrin, Preparation and Use in Dermatology.

The goal of these recommendations is to provide a framework to practitioners for implementing useful, evidence-based recommendations for the preparation of platelet-rich fibrin (PRF) and its use in various dermatological indications. The Indian Association of Dermatologists, Venereologists and Leprologists (IADVL) assigned the task of preparing these recommendations to its taskforce on platelet-rich plasma. A comprehensive literature search was done in the English language on the PRF across multiple databases. The grade of evidence and strength of recommendation was evaluated on the GRADE framework (Grading of Recommendation, Assessment, Development and Evaluation). A draft of clinical recommendations was developed on the best available evidence which was also scrutinized and critically evaluated by the IADVL Academy of Dermatology. Based on the inputs received, this final consensus statement was prepared. A total of 40 articles (meta-analyses, prospective and retrospective studies, reviews [including chapters in books] and case series) were critically evaluated and the evidence thus gathered was used in the preparation of these recommendations. This expert group recommends use of A-PRF+ protocol, that is (200 g for 8 min) for preparation of solid PRF and C-PRF protocol (700 g for 8 min) for liquid PRF. Swing out bucket model of centrifuge or the horizontal centrifuge is recommended for preparation of both PRF, and liquid PRF. Centrifugation must begin within 90–120 s of drawing of blood. PRF can be used in various indications for skin rejuvenation and nonhealing ulcers as either monotherapy or in combination with other therapies.