Controversies related to scientific report describing g-forces from studies on platelet-rich fibrin: Necessity for standardization of relative centrifugal force values

Evaluation of effect on stability of implants with and without platelet rich fibrin using a resonance frequency analyzer - An in-vivo study

Background

Although the conventional replacement for lost teeth has been partial or full dentures, the need for a fixed, esthetic, and functional restoration makes dental implants a reliable alternative.

Aim

To evaluate the initial and final stability of platelet rich fibrin coated implants using resonance frequency analyzer.

Method

ology: Thirteen patients with two or more missing teeth were informed about the procedure, and a consent form was obtained after cone beam computer tomography evaluation. Blood was drawn from the anticubital area of the patient, which was centrifuged to obtain platelet-rich fibrin. In all, 26 implants were placed, among which 13 were platelet-rich fibrin-coated (test group) and 13 were without platelet-rich fibrin (control group), and implant stability quotient values were recorded.

Results

The mean age of the patients was 34.4 (SD = 4.28). Majority of the patients were males (9; 69.2%) whereas there were only four (30.8%) female patients. When comparison between overall primary implant stability with and without PRF was done, the mean difference was 5.12 and this difference was not statistically significant (p = 0.221) whereas a statistically significant difference (p = 0.019) was found when comparison between overall secondary implant stability was done with and without PRF. The primary and secondary stability values for the control group were 69.18 ± 7.45 and 73.84 ± 8.21 respectively, and the primary and secondary stability values for the test group were 64.06 ± 12.66 and 81.49 ± 7.61 respectively, which showed statistically significant differences among the groups. The difference in these values signify that primary stability is more in control group whereas secondary stability is more in case group. This signifies that PRF enhances the stability of implant.

Conclusion

Implants coated with platelet-rich fibrin exhibited better osseointegration than implants without platelet-rich fibrin.

Platelet rich fibrin and simvastatin-loaded pectin-based 3D printed-electrospun bilayer scaffold for skin tissue regeneration

Designing multifunctional wound dressings is a prerequisite to prevent infection and stimulate healing. In this study, a bilayer scaffold (BS) with a top layer (TL) comprising 3D printed pectin/polyacrylic acid/platelet rich fibrin hydrogel (Pec/PAA/PRF) and a bottom nanofibrous layer (NL) containing Pec/PAA/simvastatin (SIM) was produced. The biodegradable and biocompatible polymers Pec and PAA were cross-linked to form hydrogels via Ca2+ activation through galacturonate linkage and chelation, respectively. PRF as an autologous growth factor (GF) source and SIM together augmented angiogenesis and neovascularization. Because of 3D printing, the BS possessed a uniform distribution of PRF in TL and an average fiber diameter of 96.71 ± 18.14 nm was obtained in NL. The Young's modulus of BS was recorded as 6.02 ± 0.31 MPa and its elongation at break was measured as 30.16 ± 2.70 %. The wound dressing gradually released growth factors over 7 days of investigation. Furthermore, the BS significantly outperformed other groups in increasing cell viability and in vivo wound closure rate (95.80 ± 3.47 % after 14 days). Wounds covered with BS healed faster with more collagen deposition and re-epithelialization. The results demonstrate that the BS can be a potential remedy for skin tissue regeneration.

Injectable platelet rich fibrin effect on laser depigmented gingiva: a clinical randomized controlled split mouth trial with histological assessment

OBJECTIVE

To determine whether intra-mucosal injection of injectable platelet-rich fibrin (i-PRF) can promote healing after Diode Laser Gingival Depigmentation (DLGD).

METHODOLOGY

A total of 20 arch sites of hyperpigmented gingiva of 10 patients underwent DLGD. For each patient, two arch sites were randomly assigned for either intra-mucosal injection of i-PRF (G1-i-PRF) (n=10 sites) or no treatment (G2-Control): (n=10 sites). Wound Healing Score (WHS), patient satisfaction, and Pigmentation Index (DOPI) were measured at 1 week and 1 and 3 months postoperatively. Histological assessment of tissue specimens was performed at baseline and 1 week.

RESULTS

The percentage change in WHS at 1 week was significantly higher in G1 (58.34±15.43) compared to G2 (37.50±11.79). At day 1, 50% of patients in G1 were pain free compared with 75% in G2, who had mild pain. Mean DOPI decreased significantly at 3 months in both groups (P-value <0.001), without significant differences between groups. G1 specimens showed significantly higher epithelial thickness (P-value <0.001), as well as a higher number of blood vessels and less percentage of inflammatory cells.

CONCLUSIONS

i-PRF demonstrated better clinical and histological healing potential and less patient discomfort compared to sites without treatment after DLGD. Registered at https://clinicaltrials.gov/ as (NCT05283668).

Platelet-rich fibrin stimulates the proliferation and expression of proteins related to survival, adhesion, and angiogenesis in gingival fibroblasts cultured on a titanium nano-hydroxyapatite-treated surface

OBJECTIVES

This in vitro study aimed to evaluate the cell viability and expression of proteins related to angiogenesis, adhesion, and cell survival (vascular endothelial growth factor, paxillin, vinculin, fibronectin, and protein kinase B) in gingival fibroblasts that were cultured on titanium discs treated with or without nanohydroxyapatite and exposed to platelet-rich fibrin (PRF)-conditioned medium.

METHODS

To obtain the conditioned medium, the PRF membranes were prepared and incubated for 48 h in a culture medium without fetal bovine serum. Analyses were performed at 24 and 48 h for the cells cultured on machined-titanium discs or surfaces treated with nanohydroxyapatite in a control medium or PRF-conditioned medium, resulting in four experimental groups (CT-TI, CT-NANO, PRF-TI, and PRF-NANO).

RESULTS

A decrease in the viability of the gingival fibroblasts was not observed in any of the experimental groups. The PRF-NANO group showed significantly higher immunoexpression of paxillin and AKT at 24 and 48 h (p < 0.01). The same result was observed for vinculin expression at 24 h (p < 0.001). The expression of fibronectin at 48 h and VEGF at 24 and 48 h was significantly higher when the cells were exposed to the PRF-conditioned medium, regardless of the disc surface (p < 0.05).

CONCLUSION

Gingival fibroblasts cultured on a nanohydroxyapatite-treated surface and in a PRF-conditioned medium showed a greater expression of proteins modulating adhesion, angiogenesis, and cell survival. Our results may contribute to the understanding of the mechanisms related to peri-implant soft tissue sealing.

Optimization of platelet-rich fibrin

The use of platelet-rich fibrin (PRF) has gained tremendous popularity in recent years owing to its ability to speed wound healing postsurgery. However, to date, many clinicians are unaware of methods designed to optimize the technology. This overview article will discuss the advancements and improvements made over the years aimed at maximizing cell and growth factor concentrations. First, a general understanding explaining the differences between RPM and RCF (g-force) is introduced. Then, the low-speed centrifugation concept, fixed angle versus horizontal centrifugation, and methods to maximize platelet concentrations using optimized protocols will be discussed in detail. Thereafter, the importance of chemically modified PRF tubes without the addition of chemical additives, as well as regulation of temperature to induce/delay clotting, will be thoroughly described. This article is a first of its kind summarizing all recent literature on PRF designed to optimize PRF production for clinical treatment.

Lyophilized platelet rich fibrin and gelatin incorporated bioadhesive bone cement composite for repair of mandibular continuity defects

Mandibular continuity defects stem from conditions such as malignancies, trauma, cysts, osteomyelitis and osteoradionecrosis, presenting significant challenges. If mandibular reconstruction fails, it can result in facial collapse, causing significant aesthetic and functional concerns for the patient. In the present study we developed a bio-adhesive Bone Cement (BC) enriched with lyophilised PRF and gelatin to enhance bone repair and induce regeneration. The developed BC consisted of a mixture of Tetracalcium Phosphate (TTCP) and O-Phospho-l-serine (OPLS) in addition to lyophilised Platelet Rich Fibrin (PRF) for sustained growth factor release and gelatin (GE) for improved cement resorption. It is primarily designed for in-situ application, conforming to the shape and size of the defect for effective bone repair and regeneration. The study evaluated four groups: (i) BC (control), (ii) BC-GE (control), (iii) BC-PRF, and (iv) BC-GE-PRF. All the four groups were characterised using FTIR, SEM and XRD. The mechanical studies of the prepared beads exhibited a significant increase in the compressive strength of the PRF loaded bone cement composites. In vitro degradation study of the beads over a 60-day period revealed a significantly higher percentage of bone cement resorption in the gelatin-incorporated groups, BC-GE (44 ± 0.5 %), and BC-GE-PRF (45 ± 2 %). The assessment of growth factor release (TGF-β and VEGF) using ELISA revealed a prolonged and sustained release of both growth factors over a 28-day period. In vitro studies were performed on human Dental Follicle Stem Cells (DFSCs) to assess cell attachment, proliferation, mineralisation and osteogenic differentiation. These studies clearly depicted that BC-PRF and BC-GE-PRF showed significantly greater proliferation of DFSCs. Furthermore, BC-PRF and BC-GE-PRF samples exhibited notably elevated expression of Runx2 and OPN (osteogenic markers), as well as a higher intensity of alizarin red stain (mineralisation). Therefore, it was concluded that PRF incorporated bioadhesive bone cement composites greatly enhance the cell attachment, proliferation, mineralisation and osteogenic differentiation of the DFSCs. Thus, the PRF and gelatin incorporated bone cement composites is expected to facilitate effective and faster bone regeneration and healing in a wide range of dental and maxillofacial defects.

Amniotic membrane versus platelet-rich fibrin in treatment of gingival recession- a randomized control trial

Objective

To determine the efficacy of latelet-rich fibrin (PRF) and Amniotic membrane (AM) along with the coronally advanced flap (CAF) technique in treating Miller's class I gingival recession (GR) defects.

Material and methods

A total of 32 sites with Miller's class I GR defects were distributed into Group A (CAF + PRF, n = 16) and Group B (CAF + AM, n = 16). Clinical parameters like gingival index (GI), plaque index (PI), gingival bleeding index (GBI), gingival sulcus depth (GSD), relative attachment level (RAL), and gingival marginal level (GML) were measured at baseline and at 3, 6 and 9 months after surgical intervention.

Results

PRF and AM with CAF were effective treatment modalities for treating Miller's class I GR defects, with an average root coverage value of 2.00 ± 0.75 mm in Group A and 1.5 ± 0.3 mm in Group B. Complete coverage (100 %) was obtained in 57 % sites of group A and 49 % sites of group B. At the 9-month follow-up, there was a significant increase in relative attachment levels in both groups when compared to baseline.

Conclusion

In the present study it was observed that there was a clinically and statistically significant improvement in root coverage with both groups. PRF-treated sites showed > 50 % complete coverage and hence were superior. AM showed comparable results to PRF and could be used as an alternative.

Do blood concentrates influence inflammatory signs and symptoms after mandibular third molar surgery? A systematic review and network meta-analysis of randomized clinical trials

OBJECTIVES

To investigate, through a network meta-analysis, the effectiveness of blood concentrates in reducing pain perception, trismus, and edema after mandibular third molar extraction.

MATERIALS AND METHODS

An electronic search was performed in nine databases to locate randomized clinical trials comparing blood concentrate use after mandibular third molar extraction. Two authors selected and extracted the data independently. The individual risk of bias in the studies was assessed with the RoB v2.0 tool. A network meta-analysis compared postoperative pain and trismus scores after applying different blood concentrates, using the mean difference (MD) as an effect estimate. The GRADE approach assessed the certainty of evidence.

RESULTS

Thirty-one randomized clinical trials were included in the review and 18 in the meta-analysis. Leukocyte- and platelet-rich fibrin (L-PRF) was the most used blood concentrate, followed by platelet-rich plasma (PRP). The network meta-analysis, depending on the analyzed period, evaluated up to 1240 surgeries. Among the analyzed blood concentrates, advanced platelet-rich fibrin (A-PRF) performed better among the analyzed blood concentrates, decreasing postoperative pain in 1, 2, 3, and 7 days and reducing trismus up to the inflammatory peak compared to blood clots. Only two studies had a low risk of bias.

CONCLUSIONS

Based on very low certainty of evidence, using concentrates seemed efficient compared to blood clots in reducing pain and trismus after mandibular third molar surgeries. A-PRF decreased postoperative pain throughout the evaluated time and trismus during the acute inflammatory peak.

CLINICAL RELEVANCE

A-PRF after mandibular third molar extractions performed better among the analyzed blood concentrates and seemed efficient in improving postoperative quality by decreasing inflammatory signs and symptoms.

Auto-dentin platelet-rich fibrin matrix is an alternative biomaterial for different augmentation procedures: A retrospective case series report

OBJECTIVES

Autologous dentin grafts derived from extracted teeth have shown promise as bone graft materials for promoting bone regeneration. This retrospective case series aimed to evaluate clinical, radiographic, and histologic outcomes of using autologous dentin matrices in various bone regeneration procedures.

MATERIALS AND METHODS

This case series included 26 eligible patients and encompassed 4 socket preservation cases, 5 cases of guided tissue regeneration, 5 cases of guided bone regeneration (GBR), 10 cases of sinus augmentation procedures, 2 immediate placement implants, and 2 socket shields. Dentin grafts were prepared from extracted teeth, cleaned, and processed. These grafts were combined with platelet-rich fibrin (PRF) to create adhesive dentin matrices, then covered with collagen membranes for simultaneous guided bone augmentation cases. Cone beam computed tomography (CBCT) scans were conducted before surgery and 4 months postoperatively to assess ridge dimensions. Histologic evaluation was performed through bone core biopsies for socket preservation cases at the 4-month mark.

RESULTS

A total of 42 implants were placed in 26 patients, with an average follow-up of 32 months. Notably, two implant failures occurred following lateral maxillary sinus augmentation. CBCT scans at the 4-month interval revealed bone coverage over implant platforms in the majority of cases. Histologic analysis from two cases of socket preservation demonstrated dentin granules enveloped by newly formed bone undergoing continuous remodeling. The quantitative histomorphometric assessment revealed a bone area of 42.8 ± 3.56%, a remaining graft area of 19.05 ± 4.58%, and a viable bone of 38.15 ± 7.84%.

CONCLUSIONS

The utilization of autologous dentin particles mixed with PRF proved effective as an alternative to conventional bone graft materials in GBR and maxillary sinus augmentation procedures. Larger controlled clinical trials are recommended to further substantiate these findings.

Technical considerations in obtaining platelet rich fibrin for clinical and periodontal research

Autologous platelet rich fibrin (PRF), is currently being widely used and investigated across the globe by clinicians and periodontal research. The technical aspect required for the procurement of PRF includes revolution per minute (RPM), relative centrifugal force (RCF) or G-force, rotor radius, rotor angle, stability or vibration in the centrifugal machine and material of test-tube, besides the systemic health of the individual may influence the final outcome. Present technical note intends to compile these aspects for better understanding and appropriate outcome while preparing PRF in varying clinical scenarios.

Understanding Solid-Based Platelet-Rich Fibrin Matrices in Oral and Maxillofacial Surgery: An Integrative Review of the Critical Protocol Factors and Their Influence on the Final Product

Platelet-rich fibrin (PRF) is a second-generation platelet concentrate whose use in clinical practice has been widely disseminated. This has led to the development of several commercial protocols, creating great confusion as to the terminology and implications of each of them. This integrative review aims to identify the critical factors of each of the phases of the solid-based PRF matrix protocol and their possible influence on their macro- and microscopic characteristics. An electronic search of the MEDLINE database (via PubMed), Web of Science, Scopus, LILACS, and OpenGrey was carried out. The search was temporarily restricted from 2001 to 2022. After searching, 43 studies were included that met the established criteria. There were numerous factors to consider in the PRF protocol, such as the material of the blood collection tubes, the duration of phlebotomy, the parameters related to blood centrifugation, the time from centrifugation to dehydration of the fibrin clots and their dehydration into membranes, as well as the time to clinical use. These factors influenced the macro- and microscopic characteristics of the PRF and its physical properties, so knowledge of these factors allows for the production of optimised PRF by combining the protocols and materials.

Platelet-rich fibrin improves the osteoneogenesis in non-critical defects in calvaria: a histological and histometric study

PURPOSE

The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF) and autograft on non-critical bone repair.

METHODS

Four bone defects (8.3 × 2 mm) were produced on the calvarium of 15 rabbits. The surgical defects were treated with either autograft, autograft associated to PRF, PRF alone, and sham. Animals were euthanized on the second, fourth or sixth posteoperative week. Histological analyses for presence of bone development on deffect was evaluated comparing the groups treated with autograft and without the autograft separately within the same period. Mann-Whitney's tests were used to compare the percentage of bone repair in each post-operative period for autograft × autograft + PRF groups and also for control × PRF groups (α = 5%).

RESULTS

No differences were observed between the groups that received autograft and autograft associated to PRF on the second and fourth postoperative week, but areas treated with PRF demonstrated significant osteogenesis when compared to sham group on the fourth and sixth weeks. The groups that received PRF (with autograft or alone) demonstrated an enlarged bone deposition when compared to their control group.

CONCLUSIONS

The use of PRF may influence bone repair and improve the bone deposition in late period of repair demonstrating osteoconductive and osteogenic properties.

Liquid platelet-rich fibrin in root surface biomodification during gingival recession treatment: Randomized, controlled, split-mouth, clinical trial

BACKGROUND AND OBJECTIVE

Free gingival graft (FGG) has been successfully used in the treatment of gingival recessions, as it is the most predictable technique for increasing the attached gingiva. This study aimed to evaluate the effect of liquid platelet-rich fibrin (PRF) with FGG on root surface coverage as root surface biomodification.

MATERIALS AND METHODS

The research sample consisted of 32 surgical sites in 16 patients, they had 2 bilateral recessions in the incisor area of the same dental arch, the sample was divided into 2 groups randomly, and liquid PRF was applied in the first group with the FGG (experimental group), and in the second group the FGG was applied alone (control group). Gingival recession depth (RD) and width of attached gingiva (WAG) were measured before starting, after 1, 3, and 6 months. The percentage of root coverage (RC) was calculated after 6 months. Healing Index (HI) was recorded after 1 week, 2 weeks, and 1 month.

RESULTS

Both groups showed a reduction in gingival RD during all follow-up periods but the difference between both groups was not statistically significant (p > 0.05) at 1 and 3 months, whereas there were significant differences at 6 months (p = 0.001). RC was better in the liquid PRF group than in the control group, but this difference was not statistically significant (p > 0.05). The postoperative 7th and 14th days HI scores of the liquid PRF group were significantly better than the control group (p = 0.000 and p = 0.004, respectively), whereas there were no significant differences in HI scores between both groups at first month (p > 0.05).

CONCLUSIONS

According to the results, the addition of liquid PRF to the root surface with FGG showed further development in terms of decreasing RD, increasing WAG, and accelerated wound-healing.

Adjunctive use of platelet-rich fibrin in surgical treatment of furcation defects: A systematic review

Periodontitis is an infectious disease characterized by the inflammatory destruction of the tooth supporting tissues. In multi-rooted teeth, this process leads to periodontal destruction within furcations creating defects demanding in terms of treatment. Regeneration of class II furcation involvement, although possible, is considered an unpredictable procedure, especially in terms of the bone fill. The interest in wound healing improvement by additional use of autologous concentrates of growth factors remains high in many fields of dentistry. Platelet-rich fibrin (PRF) is a second-generation platelet concentrate and biomaterial. PRF forms a solid fibrin matrix, which is slowly remodeled comparable to the natural blood clot. Its utilization is associated with release of growth factors and glycoproteins over a long period of time. PRF activates alkaline phosphates, which show osteoblastic activity and this activation influences the bone formation. The aim of this review of randomized controlled trials (RCTs) was to evaluate the adjunctive use of platelet-rich fibrin in surgical treatment of furcation defects.

Autologous platelet-rich fibrin promotes wound healing in cats

Street cats commonly present large skin wounds that pose significant challenges in veterinary practice. Platelet-rich fibrin (PRF) is a second-generation platelet concentrate increasingly used in humans to promote wound healing. Ease of use and clinical success in humans has prompted interest in using PRF in veterinary practice. However, until now, there is no reported study on the use of autologous PRF in feline wound management. This study evaluated the effect of application of autologous PRF in cats with naturally occurring cutaneous wounds. 16 cats with full-thickness cutaneous acute/subacute wounds were randomly allocated to PRF or Control (standard care) groups. Each cat was enrolled for 2 weeks. PRF was prepared according to previously described procedures. PRF was applied on Days 1 and 4 in addition to standard wound care. Wound size was measured using tracing planimetry. Wound surface area was calculated using SketchAndCalc^™ software on scanned tracing images. Average wound sizes at enrolment were 8.39 cm² (Control) (standard deviation (SD) 5.08 cm²) and 9.18 cm² (PRF) (SD 3.71 cm²) (range 2.42-15.97 cm²). By Day 14, the mean wound size for the Control group was 2.17 cm² (SD 1.52 cm²) and for the PRF was 0.62 cm² (SD 0.44 cm²) (p = 0.015). At Day 14, the PRF group showed mean 93.85% wound contraction with SD 3.66, while the control group showed mean 76.23% wound contraction with SD 5.30 (p = <0.0001). Based on the results, PRF could be further investigated to promote wound healing in cats as a low-risk and convenient adjunctive therapy.

Does the Choice of Preparation Protocol for Platelet-Rich Fibrin Have Consequences for Healing and Alveolar Ridge Preservation After Tooth Extraction? A Meta-Analysis

PURPOSE

Multiple preparation protocols for platelet-rich fibrin (PRF) are in use today, and clinical results are often heterogeneous. This study analyzes the impact of the chosen PRF preparation protocol on 1) wound healing and 2) alveolar ridge preservation.

METHODS

For this systematic review and meta-analysis, eligible studies were identified in PubMed and Cochrane databases. Included were randomized controlled and controlled clinical trials with healthy patients treated with PRF after atraumatic tooth extraction compared to untreated socket(s), reporting at least one of the following outcome variables: pain, swelling, soft tissue healing, alveolar osteitis risk, horizontal and vertical bone loss, socket fill, and new bone formation. Main predictor variable was relative centrifugal force (RCF) comparing high RCF (high PRF), intermediate RCF (standard [S-PRF]), low RCF (advanced PRF), and various RCF settings (concentrated growth factor preparation [CGF]). The type of centrifugation tubes (silica-coated plastic and glass) was a secondary predictor. Weighted or standardized mean differences, risk ratio and corresponding 95% confidence intervals were calculated.

RESULTS

Forty studies published between 2012 and 2022 were selected. The pooled effects of all outcomes were significant against untreated sockets. Within the subgroups high PRF or advanced PRF had the lowest efficacy for many outcome parameters. Pain reduction (in visual analog scale units) was highest for S-PRF (-1.18 [-1.48, -0.88], P < .00001) and CGF (-1.03 [-1.16, -0.90], P < .001). The risk ratio of alveolar osteitis (0.09 [0.01, 0.69], P < .02) and soft tissue healing (standardized mean difference = 2.55 [2.06, 3.03], P < .001) were best for CGF. No subgroup differences were found for bone-related outcomes. No meaningful analysis of the tube material effect was possible.

CONCLUSION

This study confirms that PRF is associated with reduced postoperative complications but indicates that preparation protocol influences clinical outcomes. S-PRF and CGF protocols appear to be superior for several outcome parameters.

Comparison of Antimicrobial Activity against Porphyromonas gingivalis between Advanced Platelet-Rich Fibrin and Injectable Platelet-Rich Fibrin

Platelet-rich fibrin (PRF) obtained via low-speed centrifugation has antimicrobial properties. This study was conducted to evaluate the effectiveness of advanced platelet-rich fibrin plus (A-PRF+) and injectable platelet-rich fibrin (I-PRF), obtained from patients with different periodontal states, against Porphyromonas gingivalis. A-PRF+ and I-PRF samples were obtained from venous blood of 60 subjects divided equally into three groups: periodontitis, gingivitis, and healthy gingiva groups. The antibacterial experiments evaluated biofilm inhibition, mature biofilm impact, and time-kill kinetics. The percent reduction in biofilm-growing and mature biofilm bacteria ranged from 39% to 49% and 3% to 7%, respectively. In the time-kill kinetics assay, PRF from the periodontitis group was more effective as an antimicrobial than that from the gingivitis and healthy gingiva group ( $p<0.001$ ); I-PRF was more effective than A-PRF+ ( $p<0.05$ ) and both of them showed peak antibacterial activity after 12 h of exposure. Both A-PRF+ and I-PRF exhibited antibacterial properties against P. gingivalis, but I-PRF appeared to be more effective. The PRF obtained from the different groups appeared to have different degrees of antimicrobial efficacy.

Network meta-analysis of platelet-rich fibrin in periodontal intrabony defects

OBJECTIVES

To evaluate the effect of platelet-rich fibrin alone or in combination with different biomaterials for the treatment of periodontal intra-bony defect.

METHODS

Up to April 2022, Cochrane library, Medline, EMBASE, and Web of Science databases were searched for randomized clinical trials. The outcomes of interest were probing pocket depth reduction, clinical attachment level gain, bone gain, and bone defect depth reduction. Bayesian network meta-analysis with 95% credible intervals was calculated.

RESULTS

Thirty-eight studies with 1157 participants were included. Platelet-rich fibrin alone or platelet-rich fibrin +biomaterials showed a statistically significant difference when compared with open flap debridement (p < 0.05, low to high certainty evidence). Neither biomaterials alone nor platelet-rich fibrin +biomaterials showed a statistically significant difference when compared to platelet-rich fibrin alone (p > 0.05, very low to high certainty evidence). Platelet-rich fibrin +biomaterials showed insignificant differences as compared to biomaterials alone (p > 0.05, very low to high certainty evidence). Allograft +collagen membrane ranked the best in probing pocket depth reduction while platelet-rich fibrin +hydroxyapatite ranked the best in bone gain.

CONCLUSION

It seems that (1) platelet-rich fibrin with/without biomaterials were more effective than open flap debridement. (2) Platelet-rich fibrin alone provides a comparable effect to biomaterials alone and platelet-rich fibrin +biomaterials. (3) Platelet-rich fibrin +biomaterials provide a comparable effect to biomaterials alone. Although allograft +collagen membrane and platelet-rich fibrin +hydroxyapatite ranked the best in terms of probing pocket depth reduction and bone gain respectively, the difference between different regenerative therapies remains insignificant, and therefore, further studies are still needed to confirm these results.

Comparative histological evaluation of two PRF formulations (PRF High and PRF Medium) on quality of life and healing outcome of apicomarginal defects: A randomized clinical trial

The objective of this randomized clinical trial was to investigate the effects of two PRF formulations (PRF High and PRF Medium) on quality of life and healing outcome (2D and 3D) of apicomarginal defects. Patients presenting with endodontic lesions and concomitant periodontal communication were randomly allocated to PRF High and PRF Medium groups. The treatment protocol in each group included a periapical surgical procedure with placement of PRF clot and membrane in the bony defect and on the denuded root surface, respectively. Quality of life was assessed for 1 week after surgery following a modified version of the patient's perception questionnaire. Postoperative pain was assessed using a visual analog scale. Clinical and radiographic evaluations were performed using Rud and Molven 2D criteria and Modified PENN 3D criteria. Buccal bone formation was assessed using sagittal and corresponding axial sections in CBCT. Histological analysis was performed using hematoxylin and eosin (H and E) staining and attaching primary antibodies to tissue sections. In total, 40 patients were enrolled in the trial (N = 20 per group). PRF Medium group patients reported significantly less swelling on the 1st (p = 0.036), 2nd (p = 0.034), and 3rd (p = 0.023) days, and average pain on the 2nd (p = 0.031), 3rd (p = 0.03), and 4th (p = 0.04) days postoperatively. The difference in success rate for periapical healing was non-significant between the PRF Medium group (89.5%) and PRF High group (90%), in both 2D and 3D imaging (p = 0.957). The formation of buccal bone was observed in five cases (26.3%) and four cases (20%) in the PRF Medium and PRF High groups, respectively, with a non-significant difference (p = 0.575). PRF Medium clots had a loose fibrin structure with a significantly higher number of neutrophils (473.79 ± 82.89 per mm²) than PRF High clots, which had a dense structure and fewer neutrophils (253.15 ± 63.86 per mm²) (p = 0.001). Autologous platelet concentrates (APCs) promoted satisfactory periapical healing, with no significant difference between the groups. Within the limitations of the study, it seems that PRF Medium should be preferred over PRF High when the patients' quality of life is the priority.

Effectiveness of using platelet-rich fibrin to increase keratinized tissue around the tooth in the modified apical reposition flap method: A split-mouth, randomized controlled trial

OBJECTIVES

One of the simplest methods to increase keratinized gingiva is the modified apically repositioned flap (MARF) technique. In this method, the periosteum remains exposed, which may lead to postoperative pain and discomfort. In the presence of bone dehiscence, bone resorption and gingival recession may occur. Hence, this study aims to use platelet-rich fibrin (PRF) to promote wound healing in the MARF technique and overcome its disadvantages.

MATERIAL AND METHODS

In this randomized controlled trial study, 10 patients (six males and four females with a mean age of 33.9 ± 11.13) with less than 2 mm of attached gingiva bilaterally were treated by the MARF + PRF membrane (test group), on the one hand, whereas, on the other hand, it was treated only by MARF (control group). Clinical parameters of keratinized gingiva include thickness, width, and vestibule depth before and 8 weeks after the intervention were measured.

RESULTS

The attached gingival width increased significantly in both groups (1.7 mm in the MARF and 2.3 mm in the PRF) and this was greater in the PRF group (p < .05). Gingival thickness in the PRF method was significantly higher than in the control group (p < .05). Probe depth, vestibular depth, and postoperative pain were not different in both groups. Wound shrinkage in the MARF group (51%) was significantly higher than in the PRF group (30%) (p < .05).

CONCLUSION

Using PRF with the MARF method significantly increased the width and thickness of the gingiva and reduced shrinkage compared to MARF only. Postoperative pain and vestibular depth changes were similar in both groups.

The efficacy of non-surgical platelet-rich fibrin application on clinical periodontal parameters and periostin level in periodontitis: Clinical trial

Platelet-rich fibrin (PRF) has been widely used in regenerative dentistry due to many growth factors produced. Periostin, a matricellular protein, is a reliable marker for tissue regeneration. Periostin is part of the cellular matrix and regulates bone homeostasis. This study aims to explore the efficacy of PRF in improvement of the clinical periodontal parameters as an adjunct to the scaling and root planing and to evaluate periostin level in gingival crevicular fluid (GCF) at baseline, 1- and 3-month recall visits. Fourteen periodontitis patients who met the inclusion criteria were recruited in this study. Two contralateral periodontal pockets with 4-6 mm in depth in each patient were selected. The sites in every participant were randomly allocated into control sites or test sites. In control sites, only conventional scaling and root planing was carried out. In test sites, however, scaling and root planing method and PRF were applied. Periostin level in GCF and clinical periodontal parameters were measured. The test sites revealed greater relative attachment gain (2.614 ± 0.606 mm and 3.321 ± 0.668 mm) than control sites (1.285 ± 0.671 mm and 1.839 ± 0.632 mm) and a significant pocket reduction (2.535 ± 0.664 mm and 3.321 ± 0.668 mm) than the control sites (1.21 ± 0.508 mm and 1.892 ± 0.655 mm) at 1- and 3-month recall visits respectively. In the test sites, level of periostin (48.83 ± 9.3 ng/μl and 98.90 ± 24.94 ng/μl) were greater than periostin levels in the control sites (42.65 ± 7.03 ng/μl and 49.29 ± 15.14 ng/μl) at 1- and 3-month recall visits respectively. In conclusion, the non-surgical application of PRF as an adjunct to scaling and root planing significantly improved the clinical periodontal parameters through raising periostin level in GCF.

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

OBJECTIVE

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.

STUDY DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

The G-Force conundrum in platelet-rich fibrin generation: Management of a problem hidden in plain sight

Aim:

A force of 400 g at 2700 revolutions per minute (RPM) results in an optimum leukocyte and platelet-rich fibrin (L-PRF). Most of centrifuges with varying characteristics generate a g-force in excess of 700 g at 2700 RPM. In this context, the study explores the effect of the original centrifugation protocol and a modified protocol tailor-made to lower the RPM to generate a g-force of ~ 400 g on platelet concentration, clot size and growth factors release in L-PRF prepared in two different commercially available centrifuges.

Materials and Methods:

Twenty five subjects each were assigned to the following groups; R₁ and R₂ where L-PRF was obtained from two laboratory swing-out centrifuges (Remi 8C^® and Remi C854^®, Mumbai, India), respectively. PRF was obtained from each subject within a group using two protocols; Original (O) protocol: conforming to the original centrifugation cycle (2700 RPM for 12 min) and Modified (M) protocol. Clot size, growth factor estimation, and platelet counts were measured at 20, 40, and 60 min from all the L-PRF clots, respectively.

Results:

At the third time period (40–60 min), there were no significant differences in clot sizes with the original protocol (P = 0.09), but a highly significant difference was noticed with the modified protocol in both the centrifuges (P = 0.001). Our results showed an increased concentration of vascular endothelial growth factor and epidermal growth factor with modified protocol than with original protocol with both the centrifuges (P = 0.001). By the end of second and third time periods, more platelet concentration was observed with modified protocol than with the original protocol in both the centrifuges (P = 0.001).

Conclusion:

This study infers that the centrifuge type and relative centrifugal force can affect the quality and quantity of cells and growth factors and an optimum relationship between g-force and RPM should be maintained to obtain L-PRF with adequate cell viability and optimum growth factor release.

Efficacy of platelet-rich fibrin in promoting the healing of extraction sockets: a systematic review

PURPOSE

To address the focused question: in patients with freshly extracted teeth, what is the efficacy of platelet-rich fibrin (PRF) in the prevention of pain and the regeneration of soft tissue and bone compared to the respective control without PRF treatment?

METHODS

After an electronic data search in PubMed database, the Web of Knowledge of Thomson Reuters and hand search in the relevant journals, a total of 20 randomized and/or controlled studies were included.

RESULTS

66.6% of the studies showed that PRF significantly reduced the postoperative pain, especially in the first 1-3 days after tooth extraction. Soft tissue healing was significantly improved in the group of PRF compared to the spontaneous wound healing after 1 week (75% of the evaluated studies). Dimensional bone loss was significantly lower in the PRF group compared to the spontaneous wound healing after 8-15 weeks but not after 6 months. Socket fill was in 85% of the studies significantly higher in the PRF group compared to the spontaneous wound healing.

CONCLUSIONS

Based on the analyzed studies, PRF is most effective in the early healing period of 2-3 months after tooth extraction. A longer healing period may not provide any benefits. The currently available data do not allow any statement regarding the long-term implant success in sockets treated with PRF or its combination with biomaterials. Due to the heterogeneity of the evaluated data no meta-analysis was performed.

Standardized Platelet-Rich Fibrin (PRF) from canine and feline origin: An analysis on its secretome pattern and architectural structure

Platelet-rich fibrin (PRF) has been incorporated in surgical procedures to promote tissue and bone healing, particularly in human medicine. The rationale for the use of platelet-based products stems from the fact that platelets, after being activated, release growth factors (GFs) and other active molecules such as cytokines, that modulate inflammation and tissue repair. Although PRF has been advanced as a therapeutic treatment for veterinary use, namely in canine and feline patients (following human medicine developments), to our knowledge a full characterization of PRF therapeutic effectors has never been performed. Herein, we studied the biological properties and release profile of GFs and other cytokines throughout ten days in in vitro culture conditions, in order to investigate the potential therapeutic ability of PRF for canine and feline practice. A protocol for obtaining PRF from whole blood without anti-coagulant from both species was optimized, originating large and homogenous PRF clots. Then, PRF clots obtained from four dogs and four cats were incubated in culture medium to assess the temporal release of platelet-derived growth factor-BB (PDGF-BB), vascular endothelial factor-A (VEGF-A), transforming growth factor β-1 (TGF-β1), and interleukin-8 (IL-8). Furthermore, morphological characterization of PRF clots, fresh and after 10 days of incubation, was performed by histology and high-resolution field emission electron scanning microscopy. In standard culture conditions, PRF clots from both species released PDGF-BB, TGF- β1 and VEGF-A, in a sustained manner, up to day 10. Moreover, PRF presents an initial burst release of IL-8, a mediator of inflammatory response which plays a key role in neutrophil recruitment and degranulation. Overall, our findings show that PRF clots may be an efficient therapeutic strategy in canine and feline clinical practice, accelerating the local healing mechanism, through the sustained delivery of signalling molecules involved in the healing cascade.

Effect of Leukocyte-Platelet Rich Fibrin (L-PRF) on Tissue Regeneration and Proliferation of Human Gingival Fibroblast Cells Cultured Using a Modified Method

BACKGROUND

An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology.

METHODS

Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit-8 assay.

RESULTS

A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration.

CONCLUSION

The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields.

Platelet-rich fibrin: An effective chronic wound healing accelerator

BACKGROUND

Platelets are cells that play a central role in wound healing, and they are the main source of the growth factor complex that plays the main role in natural wound healing. It is aimed to present the beneficial effects of topical application of PRF on chronic ulcers that do not respond to standard wound care in cases of chronic ulcers that require a long treatment process and high costs.

MATERIALS AND METHODS

The study included 16 patients between the dates of January 2017 and September 2019. The study was approved by the local ethics board and planned retrospectively.

RESULTS

The mean number of PRF applications in the patients was 4.37 (range: 1-8), while the wounds of 10 patients were completely closed up to the mean number of applications, and at least 50% of the wounds of 4 patients were closed up to the mean number of applications.

DISCUSSION

Choukroun's platelet-rich fibrin may be considered as a 2nd-generation platelet concentration. Its preparation protocol is reported to be highly simple and low-cost.

CONCLUSION

PRF is a safe, practical, easy to use adjuvant treatment method which has a potential for closing chronic wounds.

Guided bone regeneration simultaneous with implant placement using bovine-derived xenograft with and without liquid platelet-rich fibrin: a randomized controlled clinical trial

OBJECTIVE

To assess augmentation success after guided bone regeneration (GBR) carried out simultaneously with implant placement using bovine-derived xenograft alone and in combination with liquid platelet-rich fibrin (liquid-PRF).

METHODS

This randomized controlled clinical trial was conducted on patients with horizontal bone deficiency in the posterior regions of the mandible. After implant placement, GBR procedures were randomly performed using liquid-PRF-enriched bovine-derived xenograft (for the test group) and with bovine-derived xenograft alone (for the control group). To assess the change in augmentation thickness, the primary outcome of the study, cone beam computed tomography was carried out at the implant sites on completion and 6 months after surgery. The secondary outcomes were marginal bone level and implant survival rate at prosthetic delivery and at 6 months, 1 year, and 2 years follow-up after loading. The significance level was set at p<0.05 for all analysis.

RESULTS

Twenty patients with 50 implants were analyzed for the test group and 20 patients with 48 implants for the control group. At 6 months postoperatively, the mean values of augmentation thickness were 1.63 ± 0.21 mm, 2.59 ± 0.34 mm, and 3.11 ± 0.36 mm for the test group and 1.34 ± 0.14 mm, 2.49 ± 0.24 mm, and 2.97 ± 0.24 mm for the control group at 2 mm, 4 mm, and 6 mm below to the implant shoulder (p < 0.001, p = 0.007, and p = 0.036, respectively). The mean marginal bone loss was found to be less than 1 mm for both study groups during the 2 years of follow-up after prosthetic loading. Implant survival rate was 100% for both study groups.

CONCLUSION

Bovine-derived xenograft alone and in combination with liquid-PRF are both successful in achieving bone augmentation around the implants and produce a small change in marginal bone level and a high implant survival rate after loading.

CLINICAL RELEVANCE

There is a lack of evidence in the literature regarding the augmentation success of liquid-PRF used in combination with bone graft substitutes. This study indicates that liquid-PRF could be used as a supportive material with bovine-derived xenograft in GBR procedures carried out simultaneously with implant placement.

Is the use of platelet-rich fibrin effective in the healing, control of pain, and postoperative bleeding in the palatal area after free gingival graft harvesting? A systematic review of randomized clinical studies

OBJECTIVE

A systematic review (SR) was conducted to answer the following focused question based on PICO strategy: In patients who were submitted to harvesting palatal free gingival graft, could platelet-rich fibrin (PRF) application in comparison with another method improve the healing, pain, and control of postoperative bleeding in the palatal area in randomized clinical trials?

METHODS

A SR was conducted according to the PRISMA guidelines. The MEDLINE (PubMed), Scopus, Embase, and Web of Science databases were searched, and hand searches were made, covering the period up to August 2020, for randomized clinical trials (RCTs) reporting the effect of PRF membrane in postoperative palatal healing management compared with any other methods. The risk of bias (RoB) of the studies included was assessed by using the RoB 2 tool.

RESULTS

The electronic search strategy identified 150 articles. After title screening and abstract reading, 141 studies were excluded, and 9 full-text publications were comprehensively evaluated. Finally, 8 articles were included in the systematic review. Six studies showed that the PRF membrane was effective in improving wound healing during the first 2 weeks. As regards patient-centered outcomes, five studies showed that PRF promoted less postoperative pain. Finally, five studies that evaluated bleeding showed that the PRF membrane improved control of postoperative bleeding. RoB was classified as low in 4 studies, 3 with some concerns, and only one study did not describe the outcome data, and as this was missing, it was not possible to verify the protocol of data analysis for this study; therefore, it was classified as having high RoB.

CONCLUSION

Within the limitations of this study, the collective evidence emerging from this SR may support the use of PRF membrane in the palatal area after free gingival graft harvesting. The results of this review must be interpreted with caution, due to the low number of RCTs included and high degree of heterogeneity among the PRF protocols. Further well-designed RCTs with accurate protocol and standard PRF parameters are required in order to gain clear understanding of the influence of PRF on wound healing and patient-centered outcomes.

CLINICAL RELEVANCE

The use of PRF membrane for the protection of the palatal donor site following free gingival graft harvesting procedures improves wound healing and patients' quality of life.

A clinical and radiographic study of implants placed in autogenous bone grafts covered by either a platelet-rich fibrin membrane or deproteinised bovine bone mineral and a collagen membrane: a pilot randomised controlled clinical trial with a 2-year follow-up

Purpose

To compare the survival and clinical performance of implants placed in sites previously augmented with autogenous bone grafts covered by either a platelet-rich fibrin (PRF) membrane (PRF group) or a standard procedure (gold standard) involving coverage of the autogenous bone graft with deproteinised bovine bone mineral and a resorbable collagen membrane (control group).

Methods

A total of 27 partially edentulous patients (test n = 14, control n = 13) with indication for staged lateral bone block augmentation and dental implant placement were included. Twenty-four months after crown placement (range: 14–32 months), patients were recalled for a final clinical and radiographic follow-up. Outcome measures were implant survival, implant crown survival, clinical parameters of the implant, peri-implant marginal bone level, marginal bone level of adjacent tooth surfaces, biological and technical complications and patient-related outcome measures.

Results

Two implants were lost in the control group (85% survival rate); none were lost in the PRF group (100% survival rate). None of the 26 initially placed implant crowns were lost, but one implant and therefore one implant crown were lost after 20 months. Consequently, the definitive implant crown survival was 92% (95% confidence interval (CI): 73–110%) in the control group and 100% in the PRF group. No statistical difference in implant survival rate (p = 0.13) or implant crown survival was seen between the groups (p = 0.28). The mean marginal bone level at the follow-up was 0.26 mm (95% CI: 0.01–0.50 mm) in the PRF group and 0.68 mm (95% CI: 0.41–0.96 mm) in the control group. The difference between the groups was − 0.43 mm (95% CI: − 0.80 to − 0.05 mm, p = 0.03), which was statistically significant (p = 0.03). Both groups demonstrated similar healthy peri-implant soft tissue values at the final follow-up.

Conclusion

Although the current study is based on a small sample of participants, the findings suggest that the methodology of the PRF and the control group approach can both be used for bone augmentation with a similar outcome. A significant, but clinically irrelevant, higher peri-implant marginal bone level was registered in the PRF group than in the control group. Patients in both groups were highly satisfied with the treatment.

Trial registration

ClinicalTrials.gov Identifier: NCT04350749. Registered 17 April 2020. Retrospectively registered.

Methodological variations affect the release of VEGF in vitro and fibrinolysis' time from platelet concentrates

Blood Concentrates (BCs) are autologous non-transfusional therapeutical preparations with biological properties applied in tissue regeneration. These BCs differ in the preparation method, in fibrin network architecture, growth factors release as well as in platelet/cell content. Methodological changes result in distinct matrices that can compromise their clinical effectiveness. The present study evaluated the influence of different g-forces and types of tubes in the release of vascular endothelial growth factor (VEGF) from platelet-rich fibrin (PRF) as a function of time. The PRF-like samples were obtained with three g-forces (200, 400, and 800 x g) for 10 minutes in pure glass tubes or in polystyrene-clot activator tubes. Scanning and Transmission electron microscopy was used to morphometric analyzes of PRF’s specimens and flow cytometry was used to quantify VEGF slow release until 7 days. Our results showed that platelets were intact and adhered to the fibrin network, emitting pseudopods and in degranulation. The fibrin network was rough and twisted with exosomic granulations impregnated on its surface. An increase in the concentration of VEGF in the PRF supernatant was observed until 7 days for all g forces (200, 400 or 800 xg), with the highest concentrations observed with 200 x g, in both tubes, glass or plastic. Morphological analyzes showed a reduction in the diameter of the PRF fibers after 7 days. Our results showed that g-force interferes with the shape of the fibrin network in the PRF, as well as affect the release of VEGF stored into platelets. This finding may be useful in applying PRF to skin lesions, in which the rapid release of growth factors can favor the tissue repair process. Our observations point to a greater clarification on the methodological variations related to obtaining PRF matrices, as they can generate products with different characteristics and degrees of effectiveness in specific applications.

Additive Effect of Platelet Rich Fibrin with Coronally Advanced Flap Procedure in Root Coverage of Miller's Class I and II Recession Defects-A PRISMA Compliant Systematic Review and Meta-Analysis

AIM

This systematic review and meta-analysis aims to assess the additive effect of leukocyte and platelet-rich fibrin (L-PRF) on coronally advanced flap (CAF) procedures in root coverage of Miller's class I and II gingival recession defects. Review methodology: A comprehensive search in MEDLINE (PubMed), Scopus and CENTRAL (the Cochrane Central Register of Controlled Trials), along with an additional hand search, provided eight randomized clinical trials to be included in this review. A total of 167 patients with 470 gingival recession defects were analyzed. A meta-analysis was carried out to assess the change in gingival thickness (GT), width of keratinized gingiva (WKG), root coverage percentage (%RC), clinical attachment level (CAL) and recession depth (RD) at all follow-ups between CAF alone and CAF + L-PRF groups for all included studies. A subgroup analysis was carried out based on recession type (single/multiple).

RESULTS

Overall, a significant improvement in GT, CAL and RD was found when treated with CAF + L-PRF. There was a trend for a positive effect in terms of an increase in WKG when using L-PRF, especially in the treatment of single recession, though significance was not achieved (p = 0.08 overall). The results of heterogeneity among the subgroups were varied and were found to be greater than 91.3% for GT and 32.8% for WKG.

CONCLUSION

L-PRF when used in addition to CAF showed favorable results for the treatment of class I and II gingival recession defects.

Platelet-Derived Products in Veterinary Medicine: A New Trend or an Effective Therapy?

Platelet-derived products (PDPs) have gained popularity, mainly due to their high concentrations of bioactive molecules such as growth factors and cytokines, which play important roles in tissue healing and regeneration. PDPs are obtained through minimally invasive procedures and their therapeutic effect has been widely recognized. In veterinary medicine, however, the lack of standard protocols to generate PDPs is a major hurdle for assessing the clinical relevance of PDP-based therapies and for their widespread usage. The aim of this review is to analyze the technical and scientific specificities of PDPs in terms of preparation methodologies, classification categorization, nomenclature, and biological proprieties to advance their future biotechnological potential in veterinary contexts.

Pain after mandibular ramus block harvesting and lateral ridge augmentation with and without involvement of platelet-rich fibrin: a randomized controlled trial

The purpose of this study was to evaluate pain after mandibular ramus block harvesting and lateral ridge augmentation. Autogenous bone block grafts were covered with platelet-rich fibrin (PRF) membranes (test group) or deproteinized bovine bone and a resorbable collagen membrane (control group). This study included 27 partially edentulous patients (test = 14, control = 13) with an indication for bone block augmentation before staged implant placement. Postoperative methylprednisolone (32 mg, day 1) and analgesics comprising ibuprofen (400 mg, four times daily) and paracetamol (1 g, four times daily) were prescribed for 1 week. Pain was recorded by the patient on a 100-mm visual analogue scale (VAS), hourly on the day of surgery and daily for the following 7 days. The average (mean ± standard deviation) maximum pain score over the whole observation period was similar in the test (13.6 ± 13.5) and control (21.0 ± 19.9) groups (P = 0.17). In conclusion, harvesting of a mandibular ramus block and lateral ridge augmentation, in conjunction with the pharmacological protocol described, is characterized by low postoperative pain. Adding PRF membranes to the surgical site generally resulted in slightly lower pain perception, although a statistically significant difference between the test and control groups was only identified on day 1 postoperative.

Effects of rotor angle and time after centrifugation on the biological in vitro properties of platelet rich fibrin membranes

This study evaluated the impact of rotor angle and time of storage after centrifugation on the in vitro biological properties of platelet-rich fibrin (PRF) membranes. Blood samples (n = 9) were processed with a vertical fixed-angle (V) or a swing-out horizontal (H) centrifuge, with 20-60 min of sample storage after centrifugation. Leukocytes, platelets, and red blood cells were counted, and fibrin architecture was observed by scanning electron microscopy (SEM). The release of FGF2, PDGFbb, VEGF, IL-6, and IL-1β was measured after incubation on culture media for 7-21 days. Cell content was equivalent in all experimental groups (p > .05). The fibrin matrix was similar for fixed-angle and horizontal centrifugation. Horizontal centrifugation induced a twofold increase in PDGF and 1.7× increase on FGF release as compared to V samples, while IL-1β was significantly reduced (p < .05). No significant difference was observed on the release of growth factors and cytokines at different times after centrifugation (p < .05). These data suggest that both angles of centrifugation produce PRF membranes with similar structure and cellularity, but horizontal centrifugation induces a higher release of growth factors. Higher times of storage after centrifugation did not impact on cell content and the release of growth factors.

Inflammatory cell profile using different autologous fibrin protocols

Autologous fibrin has been widely used in surgical procedures for both soft and hard tissue repair. There are different protocols and devices to obtain this matrix, with varying centrifugal time, gravity force, speed, angle of the sample tube and spinning radius. The aim of this study was to compare three methods of obtaining autologous fibrin: L-PRF using the Intra-Spin L-PRF centrifuge (Dohan protocol), the advanced PRF (A-PRF) using the Intra-Spin L-PRF centrifuge and autologous leukocyte fibrin (ALF), using the Kasvi centrifuge. Venous blood was collected from 7 healthy volunteers, which were submitted to the 3 different methods of centrifugation. The membranes were tissue-processed and evaluated by immunohistochemistry for CD3, CD20, CD68 and CD138. For CD68+, a lower number of cells was immunolabelled in the L-PRF group when compared to the other groups (A-PRF and ALF). For CD3+, a lower number of immunolabellated cells was observed in the ALF group when compared to the remaining groups (p < 0.05). In the A-PRF group, the CD20+ cell count was lower than in the remaining groups. No difference was observed in CD138+ cell counts between the groups. The 3 protocols tested are suitable for obtaining autologous fibrin membranes.

Use of Platelet-Rich Fibrin in the Treatment of Grade 2 Furcation Defects: Systematic Review and Meta-Analysis

In periodontitis patients, furcation defects are crucial sites to regenerate due to their complex anatomy. Various modern surgical techniques and use of biomaterials have been suggested in the literature. Among all, platelet-rich fibrin (PRF) has potential in tissue regeneration thanks to its role in the release of growth factors. Therefore, the purpose of this study was to evaluate the beneficial effect of the addition of PRF to open flap debridement (OFD) or as an adjuvant to other biomaterials such as bone grafts in the treatment of grade 2 mandibular furcation defects. Systematic research was carried out on the databases Medline, Scopus, Embase, and Cochrane Library and registered on PROSPERO (CRD42020167662). According to the PICO guidelines by Cochrane, randomized trials and prospective non-randomized trials were evaluated, with a minimum follow-up period of 6 months. The inclusion criteria were the absence of systemic diseases, non-smoking patients, and a population aged from 18 to 65 years. Vertical pocket probing depth (PPD), vertical clinical attachment level (VCAL), and gingival recession (REC) were the primary outcomes. Vertical furcation depth (VFD), and the percentage of bone defect fill (%v-BDF) were considered as secondary outcomes. A meta-analysis of the primary and secondary outcomes was performed. Publication bias was assessed through a funnel plot. Eighty-four articles were initially extracted. Eight randomized clinical trials were analyzed according to the exclusion and inclusion criteria. The Quality assessment instrument (QAI) revealed four articles at low risk of bias, one at moderate, and three at high risk of bias. The metanalysis showed significant data regarding PPD, VCAL, VFD and %v-BDF in the comparison between PRF + OFD vs. OFD alone. The adjunct of PRF to a bone graft showed a significant difference for VCAL and a not statistically significant result for the other involved parameters. In conclusion, the adjunctive use of PRF to OFD seems to enhance the periodontal regeneration in the treatment of grade 2 furcation defects. The combination of PRF and bone graft did not show better clinical results, except for VCAL, although the amount of literature with low risk of bias is scarce. Further well-designed studies to evaluate the combination of these two materials are therefore needed.

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

Purpose

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.

Methods

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.

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.

Conclusions

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.

Histology of augmented autogenous bone covered by a platelet-rich fibrin membrane or deproteinized bovine bone mineral and a collagen membrane: A pilot randomized controlled trial

OBJECTIVES

This study aimed to evaluate histologic and histomorphometric bone characteristics with a focus on vitality after lateral alveolar ridge augmentation using an autogenous bone graft as a block covered by either a platelet-rich fibrin (PRF) membrane (test group) or a standard procedure involving coverage of the bone block with a deproteinized bovine bone mineral and a resorbable collagen membrane (control group).

MATERIAL AND METHODS

A total of 27 (test = 14, control = 13) partially edentulous patients with indication for bone block augmentation before implant installation were included. For analyses, a biopsy of augmented bone was retrieved six months after bone grafting.

RESULTS

Histologic evaluation of augmented bone revealed a predominance of non-vital bone toward the periosteum and few localized areas of vital bone in the center of the graft in both groups. In contrast, augmented bone toward the native bone demonstrated extensive bone remodeling in both groups. Histomorphometric analyses demonstrated a mean of 14% vital bone, 80% non-vital bone, 5% soft tissue, and 1% blood vessels in the test group. In the control group, the corresponding shares were 14% vital bone, 63% non-vital bone, 22% soft tissue, and 1% blood vessels. We observed no significant differences between the groups (p > .05).

CONCLUSION

In conclusion, a comparable low bone vitality of augmented bone was observed in the PRF and in the control group. Consequently, the present study could not verify the potential beneficial effect of a PRF membrane on bone vitality of an autogenous bone graft used as a block.

Autologous platelet-rich fibrin stimulates canine periodontal regeneration

Platelet-rich fibrin (PRF) provides a scaffold for cell migration and growth factors for promoting wound healing and tissue regeneration. Here, we report using PRF in periodontal healing after open flap debridement (OFD) in canine periodontitis. A split-mouth design was performed in twenty dogs. Forty periodontitis surgical sites were randomly categorized into 2 groups; OFD alone and OFD with PRF treatment. Clinical parameters of periodontal pocket depth, gingival index, and the cemento-enamel junction-alveolar bone levels/root length ratio were improved in the OFD + PRF group. The OFD + PRF group also demonstrated a dramatically decreased inflammatory score compared with the OFD group. Collagen accumulation was improved in the OFD + PRF group at later time points compared with baseline. PRF application also significantly reduced inflammatory cytokine expression (TNFA and IL1B), and promoted the expression of collagen production-related genes (COL1A1, COL3A1, and TIMP1) and growth factors (PDGFB, TGFB1, and VEGFA). These findings suggest that PRF combined with OFD provides a new strategy to enhance the overall improvement of canine periodontitis treatment outcomes, especially in terms of inflammation and soft tissue healing. Therefore, PRF use in treating periodontitis could play an important role as a regenerative material to improve canine periodontitis treatment.

Efficacy of Platelet-Rich Fibrin in Secondary Cleft Alveolar Bone Grafting

The main objective of this article is to evaluate the efficacy of platelet-rich fibrin (PRF) for secondary alveolar bone grafting. Patients between 9 and 14 years of age were included in study and were divided in two groups: Group 1—iliac bone with PRF and group 2—iliac bone without PRF. Radiographic assessment was done preoperatively, immediate postoperatively, and at 3, 6, and 9 months, respectively. Vertical bone height was assessed using 4-point scale. In group 1, 14 patients showed grade 1 resorption at 3 months and at 6 and 9 months all patients showed grade 1 resorption. In group 2, 16 patients had grade 1 resorption at 3 months, 2 patients had grade 2 resorption at 6 months, and 6 patients had grade 2 resorption at 9 months. Use of PRF growth factor with autogenous bone results in greater osteogenic effect which increases new bone regeneration and better wound healing.

Effect of platelet-rich fibrin on cell proliferation, migration, differentiation, inflammation, and osteoclastogenesis: a systematic review of in vitro studies

Objective

To systematically assess the effects of platelet-rich fibrin (PRF) on in vitro cellular behavior.

Methods

A systematic electronic search using MEDLINE database was performed. In vitro studies using PRF were considered and articles published up to June 31, 2018 were screened. Eligible studies were selected based on the use of human PRF.

Results

In total, 1746 titles were identified with the search terms, from these 37 met the inclusion criteria and were chosen for data extraction. In addition, 16 new studies, mainly published in 2019, were also included in the analysis resulting in 53 studies. No meta-analysis could be performed due to the heterogeneity of study designs. Included studies show that PRF enhances proliferation, migration, adhesion, and osteogenic differentiation on a variety of cell types along with cell signaling activation. Furthermore, PRF reduces inflammation, suppresses osteoclastogenesis, and increases the expression of various growth factors in mesenchymal cells.

Summary and conclusions

Despite some notable differences of the studies, the overall findings suggest a positive effect of PRF on cell proliferation, migration, adhesion, differentiation, and inflammation pointing towards a therapeutic potential in regenerative dentistry.

Clinical relevance

PRF serves as a reservoir of bioactive molecules to support wound healing and bone regeneration. Although the cellular mechanisms by which PRF supports the clinical outcomes remain unclear, in vitro research provides possible explanations. This systematic review aims to provide an update of the existing research on how PRF affects basic physiological processes in vitro. The overall findings suggest that PRF induces cell proliferation, migration, adhesion, and differentiation along with possessing anti-inflammatory properties further supporting its therapeutic potential in wound healing and bone regeneration.

Incorporating antibiotics into platelet-rich fibrin: A novel antibiotics slow-release biological device

BACKGROUND

The aim of the present in vitro study was to explore the possibility of using platelet-rich fibrin (PRF) as a local sustained released device for antibiotics.

MATERIALS AND METHODS

Platelet-rich fibrin was prepared with the addition of antibiotics (5 mg/ml metronidazole; 150 mg/ml clindamycin; 1 mU/ml penicillin) or saline prior to centrifugation, while collagen sponges served as control. PRFs anti-bacterial properties were examined in an anti-biogram assay with Staphylococcus aureus or Fusobacterium nucleatum at different time intervals after PRF preparation.

RESULTS

The addition of antibiotic solutions at volumes of 2 or 1 ml led to significant changes in PRF's physical properties, while the addition of 0.5 ml solution did not. PRF with saline showed minor anti-bacterial activity, while all PRFs with antibiotics showed significant anti-bacterial activity (p < 0.05). No differences were observed between raw (clot) and pressed (membrane) forms of PRF. Collagen sponges with and without antibiotics showed similar results to PRF. PRF and collagen sponges with antibiotics preserved their anti-bacterial properties 4 days after preparation.

CONCLUSIONS

Platelet-rich fibrin incorporated with antibiotics showed long-term anti-bacterial effect against F. nucleatum and S. aureus. This modified PRF preparation may be used to reduce the risk of post-operative infection in addition to the beneficial healing properties of PRF.

Effects of L-PRF and A-PRF+ on periodontal fibroblasts in in vitro wound healing experiments

Objective

To determine whether leukocyte‐platelet‐rich fibrin (L‐PRF) and advanced platelet‐rich fibrin (A‐PRF+) differ in their in vitro capacity to induce proliferation and migration of periodontal fibroblasts.

Background

L‐PRF and A‐PRF + are autologous materials used in periodontal regenerative surgery. They derive from blood from patients, but have different characteristics. The literature is controversial regarding the effects of the two PRF preparations on periodontal tissue fibroblasts.

Materials and methods

L‐PRF and A‐PRF + membranes were prepared from eight patients and incubated in 3 mL of culture medium for 2 days. Gingival fibroblasts (G‐F) and periodontal ligament fibroblast (PDL‐F) primary cells were retrieved from 7 donors. These cells were pre‐cultured for 1 day in wound healing experiment plates leaving a gap of 500 ± 50 µm in a concentration of 3.3 x 10⁵ cells/mL. 70 µL of the cell suspension was placed in each half of the well. Thereafter, the pre‐cultured L‐PRF and A‐PRF + supernatants were added to the experimental plates, and the fibroblasts were incubated for another 24 h. Medium alone (NEG) and fibroblast growth factor II (FGF) were used as controls. Subsequently, cell migration was registered for 24 h with live cell imaging in a time frame microscope at 5% CO₂ in air at 37°C. Images were analyzed using ImageJ. Cell proliferation and cell viability were measured.

Results

L‐PRF and A‐PRF + induced higher cell proliferation than FGF and NEG. Both A‐PRF + and L‐PRF induced significant faster artificial wound closure than controls. Both PRF conditioned media induced faster cell migration in the initial phase (P < .01), but in the stoppage phase, the induced migration was higher for the A‐PRF+, compared with L‐PRF (P < .01).

Conclusion

L‐PRF and A‐PRF + have a stimulatory effect on migration and proliferation of periodontal fibroblasts, and artificial wound closure was longer sustained by A‐PRF + than L‐PRF.

Usefulness of platelet-rich fibrin as a hemostatic agent after dental extractions in patients receiving anticoagulant therapy with factor Xa inhibitors: a case series

PURPOSE

To evaluate the clinical outcomes of platelet-rich fibrin (PRF) application for hemostasis after dental extraction in patients receiving anticoagulant therapy with factor Xa inhibitors.

METHODS

In total, 25 patients receiving anticoagulant therapy with rivaroxaban or apixaban who required routine dental extraction were evaluated. In all patients, PRF was used for hemostasis in addition to adapting sutures. Bleeding was subjectively assessed using a sterilize gauze pad at 24, 48, and 72 h after the procedure.

RESULTS

All invited participants (n = 25) consented to participate. The PRF clots successfully arrested bleeding after extraction in all patients, with no complications at any time point after the procedure. Favorable soft tissue healing was observed during suture removal at 10 days after the procedure in all patients, with no signs of infection or late healing.

CONCLUSIONS

The results of this case series indicate that PRF is a promising natural hemostatic agent for the management of bleeding after dental extraction in patients receiving factor Xa inhibitor therapy. Further controlled clinical studies with larger patient samples are necessary to clarify the findings of this case series.

A Proof of the Low Speed Centrifugation Concept in Rodents: New Perspectives for In Vivo Research

IMPACT STATEMENT

This study evaluated for the first time the composition and bioactivity of platelet-rich fibrin (PRF) produced from small animal blood by reducing the initial blood volume needed for the preparation of PRF from 10 to 3 mL. The results showed that different preparation protocols of PRF produced using 3 mL of animal blood exhibit the same composition, properties, and bioactivity as PRF prepared using 10 mL human blood.

Comparison of platelet-rich fibrin (PRF) produced using 3 commercially available centrifuges at both high (~ 700 g) and low (~ 200 g) relative centrifugation forces

OBJECTIVES

Platelet-rich fibrin (PRF) has gained tremendous momentum in recent years as a natural autologous growth factor derived from blood capable of stimulating tissue regeneration. Owing to its widespread use, many companies have commercialized various centrifugation devices with various proposed protocols. The aim of the present study was to compare 3 different commercially available centrifuges at both high and low g-force protocols.

MATERIALS AND METHODS

PRF was produced on three commercially available centrifuges including the IntraSpin Device (IntraLock), the Duo Quattro (Process for PRF), and Salvin (Salvin Dental). Two separate protocols were tested on each machine including the original leukocyte and platelet-rich fibrin (L-PRF) protocol (~ 700 RCF max (~ 400 RCF clot) for 12 min) as well as the advanced platelet-rich fibrin (A-PRF+) protocol (~ 200 g RCF max (~ 130 g RCF clot) for 8 min). Each of the tested groups was compared for cell numbers, growth factor release, scanning electron microscopy (SEM) for morphological differences, and clot size (both weight and length/width).

RESULTS

The present study found that PRF clots produced utilizing the low-speed centrifugation speeds (~ 200 g for 8 min) produce clots that (1) contained a higher concentration of evenly distributed platelets, (2) secreted higher concentrations of growth factors over a 10 day period, and (3) were smaller in size. This was irrespective of the centrifugation device utilized and consistently observed on all 3 devices. The greatest impact was found between the protocols utilized (up to a 200%). Interestingly, it was further revealed that the centrifugation tubes used had a much greater impact on the final size outcome of PRF clots when compared to centrifugation devices. It was found that, in general, the Process for PRF tubes produced significantly greater-sized clots when compared to other commercially available tubes. The Salvin Dental tubes also produced significantly greater PRF clots when compared to the IntraLock tubes on each of the tested centrifugation devices.

CONCLUSIONS

The present study demonstrated the reproducibility of a scientific concept (reduction in RCF produces PRF clots with more evenly distributed cells and growth factors) utilizing different devices. Furthermore, (and until now overlooked), it was revealed for the first time that the centrifugation tubes are central to the quality production of PRF. Future research investigating tube characteristics thus becomes critically important for the future optimization of PRF.

CLINICAL RELEVANCE

This is the first study to reveal the marked impact of centrifugation tubes on the final production of PRF. Future study thus becomes markedly important to further optimize the quality of PRF-based matrices. It was further found that little variability existed between the centrifugation devices if optimized centrifugation protocols (lower centrifugation speeds) were utilized.