The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors, and fibrin architecture of a leukocyte- and platelet-rich fibrin (L-PRF) clot and membrane

Influence of haematological parameters on size of the advanced platelet-rich fibrin+ (A-PRF+) in the horse

The advanced-PRF+ (A-PRF+) is a platelet concentrate, showing a higher concentration of growth factors, an increased number of cells and looser structure of the fibrin clot than leukocyte-PRF. A high variability in the size of PRF associated with patients, haematological features and centrifugation protocols was reported. The aims of this study were to evaluate the feasibility of A-PRF+ production in the field and the correlation between haematological parameters, macroscopic and microscopic features in equine A-PRF+. Samples from twenty Standardbred horses (3-7 years) were harvested with glass tubes without anticoagulants, previously heated at 37 °C. Blood samples were centrifugated at 1300 rpm for 8 min with a fixed-angle centrifuge and a horizontal centrifuge in the field, at a temperature of 15-17 °C. Clots were measured and placed on the Wound Box® for a 2-min compression. Membranes were measured and fixed in 10% formalin for histological examination. Clot and membrane surface did not differ between sex and centrifuge. Haematological parameters did not show a significant correlation to clot and membrane size. Membranes obtained from both centrifugation protocols showed a loose fibrin structure and cells evenly distributed throughout the clot. Tubes' warming was effective to obtain A-PRF+ clots from all samples, regardless the environmental temperature. Further studies are needed to evaluate the influence of other blood molecules on the A-PRF+ structure and size.

How to explain the beneficial effects of leukocyte- and platelet-rich fibrin

The survival of an organism relies on its ability to repair the damage caused by trauma, toxic agents, and inflammation. This process involving cell proliferation and differentiation is driven by several growth factors and is critically dependent on the organization of the extracellular matrix. Since autologous platelet concentrates (APCs) are fibrin matrices in which cells, growth factors, and cytokines are trapped and delivered over time, they are able to influence that response at different levels. The present review thoroughly describes the molecular components present in one of these APCs, leukocyte- and platelet-rich fibrin (L-PRF), and summarizes the level of evidence regarding the influence of L-PRF on anti-inflammatory reactions, analgesia, hemostasis, antimicrobial capacity, and its biological mechanisms on bone/soft tissue regeneration.

Comprehensive evaluation of advanced platelet-rich fibrin in common complications following sagittal split ramus osteotomy: a double-blind, split-mouth, randomized clinical trial

The sagittal split ramus osteotomy (SSRO) carries potential risks and complications. A double-blind, split-mouth, randomized clinical trial was performed, involving 30 patients undergoing mandibular setback. Advanced platelet-rich fibrin (A-PRF) was applied to one side, and the other side served as a control. The volume of postoperative drainage over 24 h was recorded. At 1, 2, and 5 days, and 3 months postsurgery, nerve recovery was assessed using the two-point discrimination test (TPD), while pain was evaluated using a visual analogue scale (VAS pain). Facial swelling was evaluated by taking linear measurements from facial reference points at the same time intervals. In the treatment group, the 24-hour drainage volume was lower (P = 0.011), pain was better on day 5 (P = 0.011), and TPD was better on day 2 (P = 0.011), day 5 (P = 0.007), and 3 months postoperatively (P = 0.020) than in the control group. There was also less facial swelling in the treatment group when compared to the baseline of 3 months postoperative (day 1, P = 0.012; day 2, P = 0.001; day 5, P = 0.011). The difference in bone mineral density (HU) at 3 months between the treatment group (469.7 ± 134.2) and the control group (348.3 ± 127.2) was statistically significant (P = 0.011), in favour of the treatment group. A-PRF may reduce postoperative complications such as neurosensory disturbance of the inferior alveolar nerve, pain, swelling, and drainage while enhancing bone healing in the osteotomy gap following SSRO. TRIAL REGISTRATION: The study was registered with the Chinese Clinical Trial Register (ChiCTR2200064534).

A Novel Use of Autologous Fibrin by Intracatheter Injection in Persistent Postoperative Biliary Defects: Technical Note on a Preliminary Experience

PURPOSE

To introduce percutaneous selective injection of autologous platelet-rich fibrin as a novel technique for persistent bile leakage repair and sharing the results of our preliminary experience.

MATERIALS AND METHODS

Seven patients (57.1% females; mean age 69.6 ± 8 years) with the evidence of persistent bile leak secondary to hepatobiliary surgery and ineffective treatment with percutaneous transhepatic biliary drainage were submitted to fibrin injection. Platelet-rich fibrin, a dense fibrin clot promoting tissue regeneration, was obtained from centrifuged patient's venous blood. Repeated percutaneous injections through a catheter tip placed in close proximity to the biliary defect were performed until complete obliteration at fistulography. Technical and clinical success were evaluated.

RESULTS

Bile leaks followed pancreaticoduodenectomy in five and major hepatectomy in two patients. Technical success defined as fibrin injection at BD site was achieved in all seven patients, and clinical success defined as a complete healing of the BD at fistulography was achieved in six patients. The median time to BD closure was 76.7 ± 40.5 days and the average procedure number was 3 ± 1 per patient. In one patient, defect persistance after four treatments required gelatin sponge injection. No major complications occurred. One case of post-procedural transitory hyperpirexia was registered.

CONCLUSION

In persistent biliary defects, despite prolonged biliary drainage stay, percutaneous injection of autologous platelet-rich fibrin appears as a readily available and feasible emergent technique in promoting fistulous tracts obliteration still mantaining main ducts patency.

Comparison of histologic and radiographic changes of sockets grafted with LPRF and sockets without intervention after tooth extraction

OBJECTIVES

After tooth extraction, marked resorption occurs in extraction socket walls, leading to functional and esthetic problems in that area. One of the methods introduced to reduce this resorption is the use of platelet derivatives. This study aimed to evaluate the effects of leukocyte and platelet-rich fibrin (L-PRF) on the changes following tooth extraction.

MATERIALS AND METHODS

The participants were 24 patients who needed to replace at least one single-rooted tooth with an implant. They were randomly divided into test and control groups. After the tooth extraction, the sockets in the test group received LPRF clots, while in the control group, the sockets were left free of any interventions. CBCT scans were obtained from the extraction site both immediately after the tooth extraction and 8 weeks later. The histologic biopsy was also obtained while the implant site was being prepared 8 weeks after the extraction.

RESULTS

The average vertical bone loss in the buccal crest was not significantly different between the two groups (1.67 ± 1.67 in the test group and 2.3 ± 1.36 in the control group; mean difference =  - 0.36, 95% CI: - 1.65-0.93, p-value = 0.57). Nor was the difference in resorption of the palatal wall (mean difference =  - 0.19, 95% CI: - 1.51.12, p-value = 0.76). The mean ridge width resorption in 25% of the coronal aspect of sockets was also measured in the test (1.30 ± 0.66) and control group (0.58 ± 0.95) (mean difference = 0.73, 95% CI: 0.03-1.42, p-value = 0.04). The new bone formation in histologic view was not statistically different between groups (p-value = 0.15).

CONCLUSION

The LPRF neither reduces the rate of ridge resorption in vertical or horizontal dimensions of extraction sockets nor induces more new bone formation.

CLINICAL RELEVANCE

This study helps dentists choose the appropriate material for ridge preservation.

Impact of aminopenicillin administration routes on antimicrobial effects of platelet-rich fibrin: An in-vitro investigation

INTRODUCTION

The aim of the study was to investigate the impact of different aminopenicillin administration routes on the antimicrobial effects of platelet-rich fibrin (PRF).

METHODS

We enrolled patients undergoing treatment with amoxicillin/clavulanic acid (AMC) orally or ampicillin/sulbactam (SAM) intravenously. AMC was applied in a single oral dose (875/125 mg), or in a double oral dose (1750/250 mg), and SAM in a dose of 2000/1000 mg. Blood was obtained one hour after the intake of AMC or 15 min after the infusion of SAM ended. Antimicrobial effects were investigated in agar diffusion tests with fresh PRF, PRF stored for 24, and PRF stored for 48 h. Agar diffusion tests were performed with Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae, and Porphyromonas gingivalis. Inhibition zones (IZs) around a 6 mm PRF disc were measured after 24 h.

RESULTS

IZs for fresh PRF and the single oral dose of AMC were 0.0, 4.7, 15.2, 2.3, and 0.9 mm (E. coli, S. aureus, S. pneumoniae, H. influenzae, and P. gingivalis, respectively). For the double oral dose, these values were 0.0, 11.4, 20.0, 8.1, and 7.4 mm. IZs for SAM were 11.9, 18.2, 24.7, 20.3, and 22.1 mm. Differences between parenteral and oral application as well as between different oral doses were significant (p<0.0001, one-way ANOVA).

DISCUSSION

The results of our study demonstrate that oral administration is a suitable route to load PRF with these drugs. This could expand the scope of PRF application to prevent infections at the surgical site, especially in an outpatient setting in which drugs are normally applied orally.

Evaluation optimum ratio of synthetic bone graft material and platelet rich fibrin mixture in a metal 3D printed implant to enhance bone regeneration

BACKGROUND

This study aims to evaluate the optimal ratio of synthetic bone graft (SBG) material and platelet rich fibrin (PRF) mixed in a metal 3D-printed implant to enhance bone regeneration.

METHODS

Specialized titanium hollow implants (5 mm in diameter and 6 mm in height for rabbit; 6 mm in diameter and 5 mm in height for pig) were designed and manufactured using 3D printing technology. The implants were divided into three groups and filled with different bone graft combinations, namely (1) SBG alone; (2) PRF to SBG in 1:1 ratio; (3) PRF to SBG in 2:1 ratio. These three groups were replicated tightly into each bone defect in distal femurs of rabbits (nine implants, n = 3) and femoral shafts of pigs (fifteen implants, n = 5). Animal tissue sections were obtained after euthanasia at the 8th postoperative week. The rabbit specimens were stained with analine blue, while the pig specimens were stained with Masson-Goldner's trichrome stain to perform histologically examination. All titanium hollow implants were well anchored, except in fracture specimens (three in the rabbit and one fracture in the pig).

RESULT

Rabbit specimens under analine blue staining showed that collagen tissue increased by about 20% and 40% in the 1:1 ratio group and the 2:1 ratio group, respectively. Masson-Goldner's trichrome stain results showed that new bone growth increased by 32% in the 1:1 ratio PRF to SBG, while - 8% in the 2:1 ratio group.

CONCLUSION

This study demonstrated that placing a 1:1 ratio combination of PRF and SBG in a stabilized titanium 3D printed implant resulted in an optimal increase in bone growth.

Towards optimized tissue regeneration: a new 3D printable bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate

Introduction

Autologous platelet concentrate (APC) are pro-angiogenic and can promote wound healing and tissue repair, also in combination with other biomaterials. However, challenging defect situations remain demanding. 3D bioprinting of an APC based bioink encapsulated in a hydrogel could overcome this limitation with enhanced physio-mechanical interface, growth factor retention/secretion and defect-personalized shape to ultimately enhance regeneration.

Methods

This study used extrusion-based bioprinting to create a novel bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate. Chemico-physical testing exhibited an amorphous structure characterized by high shape fidelity. Cytotoxicity assay and incubation of human osteogenic sarcoma cells (SaOs2) exposed excellent biocompatibility. enzyme-linked immunosorbent assay analysis confirmed pro-angiogenic growth factor release of the printed constructs, and co-incubation with HUVECS displayed proper cell viability and proliferation. Chorioallantoic membrane (CAM) assay explored the pro-angiogenic potential of the prints in vivo. Detailed proteome and secretome analysis revealed a substantial amount and homologous presence of pro-angiogenic proteins in the 3D construct.

Results

This study demonstrated a 3D bioprinting approach to fabricate a novel bioink of alginate/cellulose hydrogel loaded with thrombocyte concentrate with high shape fidelity, biocompatibility, and substantial pro-angiogenic properties.

Conclusion

This approach may be suitable for challenging physiological and anatomical defect situations when translated into clinical use.

Delayed centrifugation weakens the in vitro biological properties of platelet-rich fibrin membranes

OBJECTIVE

To investigate how delayed blood centrifugation affects the composition of the resultant platelet rich fibrin membrane (PRF, a concentrated growth factor preparation) and its biological effects towards gingival fibroblasts.

MATERIALS AND METHODS

Blood samples were collected from 18 healthy individuals and centrifuged immediately (T-0), or after a 1-6-minute delay (T-1-6, respectively), to generate PRF. Each PRF membrane was weighed. T-0 and T-6 membranes were incubated for 48 h in cell culture medium at 37 °C to create PRF "releasates" (soluble factors released from the PRF). Human gingival fibroblasts were incubated for 48 h with or without the releasates, followed by RNA isolation and real-time polymerase chain reaction to measure expression of select genes associated with granulation tissue formation, angiogenesis and wound contraction. Additional T-0 and T-6 membranes were used for visualization of leucocyte nuclei and platelets by immunostaining.

RESULTS

Immediate centrifugation (T-0) resulted in the largest membranes, T-6 membranes being on average 29% smaller. Leucocytes and platelets were significantly more abundant in T-0 than in T-6 samples. Majority of the fibroblast genes studied were consistently either upregulated or downregulated by the T-0 PRF releasates. However, centrifugation after a 6-minute delay significantly weakened the fibroblast responses.

CONCLUSIONS

Delayed centrifugation resulted in smaller PRF membranes with fewer leucocytes and platelets and also significantly reduced on the expression of a set of healing-related gingival fibroblast genes.

CLINICAL RELEVANCE

The higher expression of wound healing-related genes in gingival fibroblasts by the immediately-centrifuged PRF membranes may increase their biological properties in clinical use.

Advanced platelet rich fibrin demonstrates improved osteogenic induction potential in human periodontal ligament cells, growth factor production and mechanical properties as compared to leukocyte and platelet fibrin and injectable platelet rich fibrin

OBJECTIVES

This cross-sectional invitro research aimed to compare and contrast the macroscopic and microscopic, mechanical and biochemical features of leukocyte-rich platelet-rich fibrin, advanced platelet-rich fibrin, and injectable platelet-rich fibrin.

MATERIALS AND METHODS

In all, 150 samples were taken from males aged 18 to 25 with good systemic health (n = 50 each for i-PRF, A-PRF, and L-PRF). The samples were assessed for clot length, clot width, membrane length and width. Microscopic parameters assessed were the distribution of cells and fibrin structure. Mechanical tests were performed for tensile strength using a universal testing machine and growth factor analysis was performed for platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF)- β on Days 1, 3 and 7 using commercially available ELISA kits. The osteogenic potential was analyzed in a culture of human periodontal ligament cells for 21 days using cell viability assay, alkaline phosphatase formation and alizarin red staining for mineralization.

RESULTS

L-PRF demonstrates statistically superior clot length, width, weight, membrane length, width and weight in comparison to A-PRF (p < 0.05). L-PRF demonstrates a denser fibrin structure in comparison to A-PRF and i-PRF (p < 0.05). The cells in L-PRF are most commonly situated in the proximal of the clot where as they are distributed in the proximal and middle aspect for A-PRF(p < 0.05). A-PRF demonstrates the highest tensile strength followed by L-PRF (p < 0.05). When growth factor release was evaluated, A-PRF showed noticeably increased release of all growth factors, namely PDGF-BB, TGF-ß, and VEGF, in comparison to i-PRF and L-PRF (p < 0.05). On days 7 and 14, the cell viability of human periodontal ligament cells in co-culture with A-PRF was statistically substantially greater than that of L-PRF and i-PRF (p < 0.05). Alkaline phosphatase levels were statistically substantially higher in A-PRF, followed by i-PRF and L-PRF on days 14 and 21 (p < 0.05). After 21 days of culture, A-PRF treated cultures had much more Alizarin Red staining than L-PRF and i-PRF cultures did (p < 0.05).

CONCLUSION

It was determined that although L-PRF exhibits greater size and weight in comparison to A-PRF and i-PRF, A-PRF has superior mechanical properties, increased growth factor releases of TGF-b, PDGF-BB, and VEGF as well as superior cell viability, alkaline phosphatase production, and mineralization on human periodontal ligament cells.

CLINICAL RELEVANCE

Based on these findings, A-PRF can be recommended for improved delivery of growth factors and osteogenesis whereas L-PRF is better-suited for applications relying on the size of membrane.

Tissue engineering innovations to enhance osseointegration in immediate dental implant loading: A narrative review

The demand for efficient and accelerated osseointegration in dental implantology has led to the exploration of innovative tissue engineering strategies. Immediate implant loading reduces treatment duration and necessitates robust osseointegration to ensure long-term implant success. This review article discusses the current studies of tissue engineering innovations for enhancing osseointegration in immediate dental implant loading in the recent decade. Keywords "tissue engineering," "osseointegration," "immediate implant loading," and related terms were systematically searched. The review highlights the potential of bioactive materials and growth factor delivery systems in promoting osteogenic activity and accelerating bone regeneration. The in vivo experiment demonstrates significantly improved osseointegration in the experimental group compared to traditional immediate loading techniques, as evidenced by histological analyses and biomechanical assessments. It is possible to revolutionize the treatment outcomes and patient satisfaction in dental implants by integrating bioactive materials and growth factors.

Multiplex Profiling of Biomarker and Drug Uptake in Single Cells Using Microfluidic Flow Cytometry and Mass Spectrometry

To perform multiplex profiling of single cells and eliminate the risk of potential sample loss caused by centrifugation, we developed a microfluidic flow cytometry and mass spectrometry system (μCytoMS) to evaluate the drug uptake and induced protein expression at the single cell level. It involves a microfluidic chip for the alignment and purification of single cells followed by detection with laser-induced fluorescence (LIF) and inductively coupled plasma mass spectrometry (ICP-MS). Biofunctionalized nanoprobes (BioNPs), conjugating ∼3000 6-FAM-Sgc8 aptamers on a single gold nanoparticle (AuNP) (Kd = 0.23 nM), were engineered to selectively bind with protein tyrosine kinase 7 (PTK7) on target cells. PTK7 expression induced by oxaliplatin (OXA) uptake was assayed with LIF, while ICP-MS measurement of 195Pt revealed OXA uptake of the drug in individual cells, which provided further in-depth information about the drug in relation to PTK7 expression. At an ultralow flow of ∼0.043 dyn/cm2 (20 μL/min), the chip facilitates the extremely fast focusing of BioNPs labeled single cells without the need for centrifugal purification. It ensures multiplex profiling of single cells at a throughput speed of 500 cells/min as compared to 40 cells/min in previous studies. Using a machine learning algorithm to initially profile drug uptake and marker expression in tumor cell lines, μCytoMS was able to perform in situ profiling of the PTK7 response to the OXA at single-cell resolution for tests done on clinical samples from 10 breast cancer patients. It offers great potential for multiplex single-cell phenotypic analysis and clinical diagnosis.

Antimicrobial effects of clindamycin-loaded platelet-rich fibrin (PRF)

OBJECTIVES

Recent research has demonstrated that platelet-rich fibrin (PRF) is an appropriate carrier for ampicillin/sulbactam. The aim of the study was to investigate whether PRF is also a suitable bio-carrier for clindamycin (CLI).

METHODS

PRF membranes were produced from 36 patients receiving intravenous therapy with CLI (e.g. due to the diagnosis of an osteonecrosis of the jaw or infections). Concentrations of CLI in PRF membranes were measured with liquid chromatography-tandem mass spectrometry, and the antimicrobial effects were investigated in vitro in agar diffusion tests with fresh PRF and PRF stored for 24 h. Storage was performed in an incubator at 36 °C to simulate the in-vivo situation.

RESULTS

The mean concentration of CLI in plasma was 1.0 ± 0.3 μg/100 mg plasma; in resulting PRF membranes 0.7 ± 0.4 μg/100 mg PRF. Agar diffusion tests were performed with Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus mitis, Porphyromonas gingivalis, and Fusobacterium nucleatum. Mean inhibition zones, in mm, for fresh PRF were 17.3, 12.2, 18.8, 17.1, 25.8 and 18.1, 12.7, 19.2, 17.3, and 26.3 for stored PRF, respectively.

CONCLUSION

The results demonstrate that PRF is a suitable bio-carrier for CLI when administered systemically to patients. The concentration in PRF generated from patients after infusion of 600 mg CLI dose suffices to target clinically relevant bacteria.

CLINICAL RELEVANCE

Using PRF as a carrier for local antibiotic application can prevent infections in oral and maxillofacial surgery. Within the study limitations, the findings could expand the scope of PRF application by adding CLI as a new antibiotic to the spectrum of PRF therapy.

The Association of Nanostructured Carbonated Hydroxyapatite with Denatured Albumin and Platelet-Rich Fibrin: Impacts on Growth Factors Release and Osteoblast Behavior

Platelet-rich Fibrin (PRF), a second-generation blood concentrate, offers a versatile structure for bone regeneration due to its composition of fibrin, growth factors, and cytokines, with adaptations like denatured albumin-enriched with liquid PRF (Alb-PRF), showing potential for enhanced stability and growth factor dynamics. Researchers have also explored the combination of PRF with other biomaterials, aiming to create a three-dimensional framework for enhanced cell recruitment, proliferation, and differentiation in bone repair studies. This study aimed to evaluate a combination of Alb-PRF with nanostructured carbonated hydroxyapatite microspheres (Alb-ncHA-PRF), and how this association affects the release capacity of growth factors and immunomodulatory molecules, and its impact on the behavior of MG63 human osteoblast-like cells. Alb-PRF membranes were prepared and associated with nanocarboapatite (ncHA) microspheres during polymerization. MG63 cells were exposed to eluates of both membranes to assess cell viability, proliferation, mineralization, and alkaline phosphatase (ALP) activity. The ultrastructural analysis has shown that the spheres were shattered, and fragments were incorporated into both the fibrin mesh and the albumin gel of Alb-PRF. Alb-ncHA-PRF presented a reduced release of growth factors and cytokines when compared to Alb-PRF (p < 0.05). Alb-ncHA-PRF was able to stimulate osteoblast proliferation and ALP activity at lower levels than those observed by Alb-PRF and was unable to positively affect in vitro mineralization by MG63 cells. These findings indicate that the addition of ncHA spheres reduces the biological activity of Alb-PRF, impairing its initial effects on osteoblast behavior.

Fractalkine modulates pulmonary angiogenesis and tube formation by modulating CX3CR1 and growth factors in PVECs

This study aimed to investigate effects of pulmonary fractalkine (FKN/CX3CL1) on angiogenesis and tube formation. Tube forming capability of pulmonary vascular endothelial cells (PVECs) was evaluated. CCK-8 assay was used to evaluate proliferation of PVECs. RT-PCR assay was used to determine angiogenesis specific biomarkers. Western blot was applied to identify CX3CR1, Akt, phosphorylated Akt (p-Akt), Erk1/2, phosphorylated Erk1/2 (p-Erk1/2), vascular endothelial growth factor A (VEGFA), and inducible nitric oxide synthase (iNOS) expression. VEGF-A and platelet-derived growth factor (PDGF) levels were examined using ELISA. FKN was safe and triggered tube formation in PVECs. FKN significantly enhanced VEGF-A, PDGF, and iNOS gene transcription compared to the Control group (p < 0.05). CX3CR1 interfering (LV5-CX3CR1 shRNA) remarkably reduced CX3CR1 expression compared to those in LV5 blank group (p < 0.05). Ratios of p-Akt/Akt and p-Erk/Erk were significantly decreased in CX3CR1 shRNA-treated PVECs administered Akt inhibitor (or Erk inhibitor) and 10 ng/mL FKN compared to CX3CR1 shRNA-treated PVECs administered 10 ng/mL FKN (p < 0.05). FKN increased VEGF-A and iNOS expression through activating Akt/Erk pathway. FKN promoted VEGF-A/iNOS expression and triggered p-Akt/Akt and p-Erk/Erk pathway through modulating CX3CR1. FKN-treated macrophages enhanced activation of Akt/Erk pathway. FKN-treated macrophages enhanced PDGF and VEGF-1 expression in PVECs. FKN modulated pulmonary angiogenesis and tube formation through modulating CX3CR1 and growth factors and activating p-Akt/Akt and p-Erk/Erk signaling pathway.

The role and mechanism of platelet-rich fibrin in alveolar bone regeneration

Platelet-rich fibrin (PRF), as an autologous blood preparation, has been receiving increasing attention in recent years and has been successfully applied in various clinical treatments for alveolar bone regeneration in the oral field. This review focuses on analyzing and summarizing the role and mechanism of PRF in alveolar bone regeneration. We first provide a brief introduction to PRF, then summarize the mechanisms by which PRF promotes alveolar bone regeneration from three aspects: osteogenesis mechanism, bone induction mechanism, and bone conduction mechanism, involving multiple signaling pathways such as Smad, ERK1/2, PI3K/Akt, and Wnt/β-catenin. We also explore the various roles of PRF as a scaffold, filler, and in combination with bone graft materials, detailing how PRF promotes alveolar bone regeneration and provides a wealth of experimental evidence. Finally, we summarize the current applications of PRF in various oral fields. The role of PRF in alveolar bone regeneration is becoming increasingly important, and its role and mechanism are receiving more and more research and understanding. This article will provide a reference of significant value for research in related fields. The exploration of the role and mechanism of PRF in alveolar bone regeneration may lead to the discovery of new therapeutic targets and the development of more effective and efficient treatment strategies.

The Use of Nano-Hydroxyapatite (NH) for Socket Preservation: Communication of an Upcoming Multicenter Study with the Presentation of a Pilot Case Report

Background and Objectives: The use of biomaterials in dentistry is extremely common. From a commercial perspective, different types of osteoconductive and osteoinductive biomaterials are available to clinicians. In the field of osteoconductive materials, clinicians have biomaterials made of heterologous bones at their disposal, including biomaterials of bovine, porcine, and equine origins, and biomaterials of natural origin, such as corals and hydroxyapatites. In recent years, it has become possible to synthesize nano-Ha and produce scaffolds using digital information. Although a large variety of biomaterials has been produced, there is no scientific evidence that proves their absolute indispensability in terms of the preservation of postextraction sites or in the execution of guided bone regeneration. While there is no scientific evidence showing that one material is better than another, there is evidence suggesting that several products have better in situ permanence. This article describes a preliminary study to evaluate the histological results, ISQ values, and prevalence of nano-HA. Materials and Methods: In this study, we planned to use a new biomaterial based on nanohydroxyapatite for implantation at one postextraction site; the nano-HA in this study was NuvaBONE (Overmed, Buccinasco, Milano, Italy). This is a synthetic bone graft substitute that is based on nanostructured biomimetic hydroxyapatite for application in oral-maxillofacial surgery, orthopedics, traumatology, spine surgery, and neurosurgery. In our pilot case, a patient with a hopeless tooth underwent extraction, and the large defect remaining after the removal of the tooth was filled with nano-HA to restore the volume. Twelve months later, the patient was booked for implant surgery to replace the missing tooth. At the time of the surgery, a biopsy of the regenerated tissue was taken using a trephine of 4 mm in the inner side and 8 mm deep. Results: The histological results of the biopsy showed abundant bone formation, high values of ISQ increasing from the insertion to the prosthetic phase, and a good reorganization of hydroxyapatite granules during resorption. The implant is in good function, and the replaced tooth shows good esthetics. Conclusions: The good results of this pilot case indicate starting the next Multicentric study to have more and clearer information about this nanohydroxyapatite (NH) compared with control sites.

Does leukocyte-platelet-rich fibrin (L-PRF) cause long term acceleration in the rate of canine retraction? A split-mouth, two-arm parallel group, randomized control trial

OBJECTIVE

The present study was conducted to investigate the effects of leukocyte-platelet-rich fibrin (L-PRF) on the rate of maxillary canine retraction for a period of 5 months.

METHODS

A split-mouth study was conducted on 16 subjects (9 males and 7 females; age range 17-25 years; mean age, 21.85±2.45 years) who required therapeutic extraction of bilateral maxillary first premolars. After the initial leveling and alignment, L-PRF plugs were placed in a randomly selected extraction socket (Experimental Group), and the other side served as a control (Control Group). Canine retraction was carried out by the activation of nickel-titanium (NiTi) closed-coil springs delivering 150 g of force. The rates of canine movement, canine rotation, tipping, root resorption, and molar movement were assessed at monthly intervals for five months (T0-T5). Pain, swelling and discomfort accompanying the procedure were assessed using a Likert scale.

RESULTS

The study revealed a significant increase in the rate of canine movement on the experimental side in the first two months, and significant molar anchorage loss was observed only in the first month for control side. There were no statistically significant differences between the groups regarding canine rotation, tipping, probing depth, root resorption, and pain perception.

CONCLUSIONS

The use of L-PRF plugs in extraction sockets considerably enhanced the rate of canine movement only in the first two months, and long-term efficacy was not observed in this study.

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.

Sema4D is diminished in leukocyte platelet-rich fibrin and impairs pre-osteoblastic MC3T3-E1 cells' functionality

OBJECTIVE

Semaphorin 4D (Sema4D) is a coupling factor expressed on osteoclasts that may hinder osteoblast differentiation. Since the leukocyte platelet-rich fibrin (L-PRF) membrane promotes growth factor concentration, this study aims to quantify the amount of Sema4D in L-PRF membranes, and analyze the impact of Sema4D on osteoblast cell function in vitro.

DESIGN

Enzyme-linked immunosorbent assay (ELISA) was used to quantify the levels of Sema4D in both L-PRF and whole blood (serum). To analyze the impairment of Sema4D on osteoblasts, MC3T3-E1 cells were induced to osteogenic differentiation and exposed to Sema4D ranging from 10 to 500 ng/ml concentrations. The following parameters were assayed: 1) cell viability by MTT assay after 24, 48, and 72 h; 2) matrix mineralization by Alizarin Red staining after 14 days, 3) Runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN), osteonectin (ONC), bone sialoprotein (BSP) and alkaline phosphatase (ALP) gene expression by qPCR. For all data, the significance level was set at 5%.

RESULTS

The amount of Sema4D in the whole blood (serum) was higher than in L-PRF. Osteoblasts exposed to Sema4D at all tested concentrations exhibited a decrease in matrix mineralization formation as well in RUNX-2, OCN, ONC, BSP, and ALP gene expression (p < 0.05).

CONCLUSION

The presence of Sema4D, a molecule known for suppressing osteoblast activity, diminishes within L-PRF, enhancing its ability to facilitate bone regeneration.

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.

Plasma Gel Made of Platelet-Poor Plasma: In Vitro Verification as a Carrier of Polyphosphate

Plasma gel (PG) is a blood-derived biomaterial that can be prepared by heating or chemical cross-linking without the aid of intrinsic coagulation activity and has gradually been applied in the field of esthetic surgery. To explore the applicability of PG in regenerative therapy or tissue engineering, in this study, we focused on the advantages of the heating method and verified the retention capacity of the resulting PG for polyphosphate (polyP), a polyanion that contributes to hemostasis and bone regeneration. Pooled platelet-poor plasma (PPP) was prepared from four healthy male adult donors, mixed with synthetic polyP, and heated at 75 °C for 10 or 30 min to prepare PG in microtubes. The PG was incubated in PBS at 37 °C, and polyP levels in the extra-matrix PBS were determined by the fluorometric method every 24 h. The microstructure of PG was examined using scanning electron microscopy. In the small PG matrices, almost all of the added polyP (~100%) was released within the initial 24 h. In contrast, in the large PG matrices, approximately 50% of the polyP was released within the initial 24 h and thereafter gradually released over time. Owing to its simple chemical structure, linear polyP cannot be theoretically retained in the gel matrices used in this study. However, these findings suggest that thermally prepared PG matrices can be applied as carriers of polyP in tissue engineering and regenerative medicine.

Optimizing Osseointegration in Dental Implantology: A Cross-Disciplinary Review of Current and Emerging Strategies

The paper explores the correlation between osteointegration and dental implant stability, investigating the relationship and its implications for successful outcomes in implant dentistry. Osteointegration, defined as the direct structural and functional connection between living bone and the implant surface, plays a crucial role in determining the stability and long-term success of dental implants. This review synthesizes current knowledge from scientific literature and clinical studies to elucidate the factors influencing osteointegration and their impact on implant stability. Surface characteristics of implants, such as topography and chemistry, as well as the surgical techniques employed during implant placement, are examined in detail, emphasizing their significant influence on osseointegration and subsequent implant stability. Additionally, host-related factors such as bone quality, systemic conditions, and patient-specific considerations are explored to further comprehend the complexity of the osteointegration process. The abstract underscores the importance of achieving an optimal bone-implant interface to ensure successful implant integration and stability. Furthermore, emerging technologies and materials, such as computer-guided implant placement and biomimetic surfaces, are discussed for their potential to enhance osteointegration and improve long-term implants.

Regenerative endodontic treatment of an immature incisor tooth with a novel platelet-rich product: A five-year follow-up case report

This case report presents a five-year follow-up and the management of a necrotic, immature incisor tooth treated by a novel platelet-rich plasma/platelet extract solution and platelet-rich fibrin (PRP-PES/PRF) and the restoration by using a stress-reduced direct composite restoration (SRDC) technique. The patient with a broken maxillary lateral tooth was referred to our clinic. Extra/intra-oral examinations were within normal limits. The nonvital tooth having an apical lesion and open-apical apex was treated with a regenerative endodontic treatment procedure (REP), and further root development with continued apical closure was shown in the follow-ups up to 60 months. In conclusion, the SRDC and PRP-PES/PRF combination can be an opportunity for the teeth requiring post-restoration. In contrast to the treatment strategy susceptible to weakening or fracturing the patient's tooth root, the REP approach may lead to a better prognosis for the patient's tooth.

Fat enhanced leukocyte-platelet-rich fibrin versus fascia lata in endoscopic reconstruction of CSF leaks

PURPOSE

The aim of this study was to use a new biological active fat enhanced leukocyte-platelet-rich fibrin membrane (L-PRF) for skull base defect reconstruction and compare its validity and reliability with the time-honored fascia lata.

METHODS

This prospective study was conducted on 48 patients with spontaneous CSF leaks who were divided into 2 matched groups by stratified randomization, 24 patients in each group. In group A we performed multilayer repair using fat enhanced L-PRF membrane. In group B we used fascia lata for the multilayer repair. In both groups we enforced the repair with mucosal grafts/flaps.

RESULTS

The two groups were statistically matched for age, sex, intracranial pressure, and site and size of the skull base defect. There was no statistically significant difference between the two groups regarding the outcome of the repair or recurrence of CSF leak during the first postoperative year. Meningitis occurred in one patient in group B and was successfully treated. Another patient in group B developed thigh hematoma which resolved spontaneously.

CONCLUSION

The fat enhanced L-PRF membrane is a valid reliable option in repair of CSF leaks. The membrane is autologous, readily available, easily prepared, and has the advange of including stromal fat, stromal vascular fraction (SVF), and leukocyte-platelet-rich fibrin (L-PRF). The present study showed that fat enhanced L-PRF membrane is stable, non-absorbable, not liable to shrink or become necrotic, and can establish good seal of the skull base defect and further enhance the healing process. The use of the membrane also has the advantage of avoiding thigh incision and possible hematoma formation.

Radiographic and immuno-histochemical evaluation of root perforation repair using MTA with or without platelet-rich fibrin or concentrated growth factors as an internal matrix in dog's teeth: in vivo animal study

OBJECTIVES

To comparatively evaluate the in vivo outcome of MTA repair for contaminated and non-contaminated furcation perforations (FP) with or without PRF and CGF as a matrix in dogs' teeth.

METHODS

Ninety dog teeth were divided into five groups based on the iatrogenic FP repair approach after doing root canal treatment: negative control (without FP), positive control (FP without repair), MTA, MTA + PRF and MTA + CGF groups, where FP were repaired promptly in subdivision 1 (n = 10; non-contaminated) and after 4 weeks of oral contamination in subdivision 2 (n = 10;contaminated). After 3 months, the perforation site was assessed radiographically (vertical bone density), histologically (inflammatory cell count, epithelial proliferation, cementum and bone deposition) and immunohistochemically (OPN and TRAP antibodies localisation). Data collected were statistically analysed using SPSS software at a 0.05 significance level.

RESULTS

The MTA + PRF and MTA + CGF groups demonstrated significantly more bone formation, OPN immunolocalisation and fewer inflammatory cell counts than MTA group. MTA, MTA + PRF and MTA + CGF groups showed significantly favourable radiographic, histological and immunohistochemical healing features than the positive control, especially in non-contaminated subdivisions, that significantly showed better features than the contaminated subdivisions (P < 0.001).

CONCLUSION

The use CGF and PRF as a matrix beneath MTA in FP repair in dog's teeth is promising as it could increase hard and soft tissue regeneration in non-contaminated and contaminated perforations.

CLINICAL RELEVANCE

The repair of FP is challenging especially when associated with contaminated inter-radicular bone loss. Radiographic, histological and immunohistochemical comprehensive evaluation of the root and surrounding attachment apparatus response to different perforation repair protocols could give a predictable clinical outcome.

Histological, Immunohistochemical, Biomechanical, and Wettability Evaluations of the Leukocyte- and Platelet-Rich Fibrin Membranes Derived from Canine Blood

This study aimed to perform histological, immunohistochemical, biomechanical, and wettability assessments of leukocyte- and platelet-rich fibrin (L-PRF) membranes obtained from the blood of healthy dogs. Ten client-owned Labrador Retriever dogs were enrolled. Blood samples were obtained from the external jugular vein using a vacuum tube without anticoagulant, which was immediately centrifuged at 400g for 12 min in a dedicated centrifuge. The L-PRF clot was removed from the tube, and the red clot was released from the buffy coat using a spatula. The membrane was produced using a PRF box. Histological examination identified the three portions of the L-PRF membranes. The first portion was composed mainly of red blood cells with the presence of a low number of leukocytes among them. The second portion was composed of white blood cells, mainly neutrophils. The third portion was composed of the fibrin network which was characterized by acidophilic staining. The immunohistochemical analysis showed that vascular endothelial growth factor and platelet-derived growth factor were expressed in all samples at different intensities, both in cellular components and fibrin mesh. The tensile test and wettability assessments were measured in membranes 30 min and 3 h after production. The 30 min L-PRF membranes supported twice the ultimate tensile strength compared to 3 h L-PRF membranes. The wettability of the 30 min sample membranes was statistically higher than the 3 h sample membranes. In conclusion, the centrifugation protocol allowed production of the L-PRF membrane using canine blood and this was confirmed by histological and immunohistochemical analysis. The mechanical resistance and wettability of the L-PRF membrane were significantly reduced over time.

Progress in Regenerative Medicine: Exploring Autologous Platelet Concentrates and Their Clinical Applications

The goal of regenerative medicine is to achieve tissue regeneration. In the past, commonly used techniques included autologous or allogeneic transplantation and stem cell therapy, which have limitations, such as a lack of donor sites in the case of autologous transplantation and the invasiveness of stem cell harvesting. In recent years, research has, therefore, focused on new and less invasive strategies to achieve tissue regeneration. A step forward in this direction has been made with the development of autologous platelet concentrates (APCs), which are derived from the patient's own blood. They can be classified into three generations: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factors (CGFs). These APCs have different structural characteristics, depending on the distinctive preparation method, and contain platelets, leukocytes, and multiple growth factors, including those most involved in regenerative processes. The purpose of this review is to clarify the most used techniques in the field of regenerative medicine in recent years, comparing the different types of APCs and analyzing the preparation protocols, the composition of the growth factors, the level of characterization achieved, and their clinical applications to date.

Research Hotspots and Trends of Bone Xenograft in Clinical Procedures: A Bibliometric and Visual Analysis of the Past Decade

BACKGROUND

Bone defect therapy is a common clinical challenge for orthopedic and clinical physicians worldwide, and the therapeutic effect affects the physiological function and healthy life quality of millions of patients. Compared with traditional autogenous bone transplants, bone xenografts are attracting attention due to their advantages of unlimited availability and avoidance of secondary damage. However, there is currently a lack of bibliometric analysis on bone xenograft. This study aimed to use bibliometric methods to analyze the literature on bone xenograft from 2013 to 2023, to explore the current status, hotspots, and future trends of research in this field, and to promote its development and progress.

METHODS

Using the Web of Science Core Collection database, we retrieved and collected publication data related to xenogeneic bone grafting materials worldwide from January 2013 to March 2023. Origin (2021), CiteSpace (6.2.R2 standard), and an online bibliometric platform were used for bibliometric analysis and data visualization.

RESULTS

A total of 3395 documents were retrieved, and 686 eligible papers were selected. The country and institutions with the highest number of publications and centrality were the United States (125 papers, centrality = 0.44) and the University of Zurich (29 papers, centrality = 0.28), respectively. The most cited author was Araujo MG (163 times), and the author with the most significant centrality was Froum SJ (centrality = 0.09). The main keyword clusters were "tissue engineering", "sinus floor elevation", "dental implants", "tooth extraction", and "bone substitutes". The most significant bursting keywords in the last three years were "platelet rich fibrin".

CONCLUSIONS

Research on bone xenograft is steadily growing and will continue to rise. Currently, research hotspots and directions are mainly focused on dental implants related to bone-augmentation techniques and bone tissue engineering. In the future, research hotspots and directions may focus on decellularization technology and investigations involving platelet-rich fibrin.

Cell damage evaluation by intelligent imaging flow cytometry

Essential thrombocythemia (ET) is an uncommon situation in which the body produces too many platelets. This can cause blood clots anywhere in the body and results in various symptoms and even strokes or heart attacks. Removing excessive platelets using acoustofluidic methods receives extensive attention due to their high efficiency and high yield. While the damage to the remaining cells, such as erythrocytes and leukocytes is yet evaluated. Existing cell damage evaluation methods usually require cell staining, which are time-consuming and labor-intensive. In this paper, we investigate cell damage by optical time-stretch (OTS) imaging flow cytometry with high throughput and in a label-free manner. Specifically, we first image the erythrocytes and leukocytes sorted by acoustofluidic sorting chip with different acoustic wave powers and flowing speed using OTS imaging flow cytometry at a flowing speed up to 1 m/s. Then, we employ machine learning algorithms to extract biophysical phenotypic features from the cellular images, as well as to cluster and identify images. The results show that both the errors of the biophysical phenotypic features and the proportion of abnormal cells are within 10% in the undamaged cell groups, while the errors are much greater than 10% in the damaged cell groups, indicating that acoustofluidic sorting causes little damage to the cells within the appropriate acoustic power, agreeing well with clinical assays. Our method provides a novel approach for high-throughput and label-free cell damage evaluation in scientific research and clinical settings.

Platelet-Rich Plasma Power-Mix Gel (ppm)-An Orthobiologic Optimization Protocol Rich in Growth Factors and Fibrin

Platelet- and fibrin-rich orthobiologic products, such as autologous platelet concentrates, have been extensively studied and appreciated for their beneficial effects on multiple conditions. Platelet-rich plasma (PRP) and its derivatives, including platelet-rich fibrin (PRF), have demonstrated encouraging outcomes in clinical and laboratory settings, particularly in the treatment of musculoskeletal disorders such as osteoarthritis (OA). Although PRP and PRF have distinct characteristics, they share similar properties. The relative abundance of platelets, peripheral blood cells, and molecular components in these orthobiologic products stimulates numerous biological pathways. These include inflammatory modulation, augmented neovascularization, and the delivery of pro-anabolic stimuli that regulate cell recruitment, proliferation, and differentiation. Furthermore, the fibrinolytic system, which is sometimes overlooked, plays a crucial role in musculoskeletal regenerative medicine by regulating proteolytic activity and promoting the recruitment of inflammatory cells and mesenchymal stem cells (MSCs) in areas of tissue regeneration, such as bone, cartilage, and muscle. PRP acts as a potent signaling agent; however, it diffuses easily, while the fibrin from PRF offers a durable scaffolding effect that promotes cell activity. The combination of fibrin with hyaluronic acid (HA), another well-studied orthobiologic product, has been shown to improve its scaffolding properties, leading to more robust fibrin polymerization. This supports cell survival, attachment, migration, and proliferation. Therefore, the administration of the "power mix" containing HA and autologous PRP + PRF may prove to be a safe and cost-effective approach in regenerative medicine.

Comparative Investigation of Anti-Inflammatory Effect of Platelet-Rich Fibrin after Mandibular Wisdom Tooth Surgery: A Randomized Controlled Study

This study evaluated the anti-inflammatory effect of platelet-rich fibrin (PRF) applied to the extraction socket after impacted mandibular third molar surgery with subjective and objective parameters. Forty-eight patients with impacted wisdom teeth in bilateral and similar positions were included in the study. The control group was formed with the standard surgery and the PRF group was formed with local PRF application in addition to standard procedure (n = 96). The anti-inflammatory activity of PRF on postoperative 2nd and 7th days was evaluated subjectively by clinical parameters and objectively by biochemical parameters. Postoperative 2nd- and 7th-day follow-up data of pain, edema, and trismus in the PRF group were found to be statistically significantly lower. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were found to be statistically significantly lower in the PRF group than the control in the postoperative 2nd-day follow-up period (p < 0.001). There was no statistically significant difference in interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) parameters when the PRF group and the control group were compared in both follow-up periods (p > 0.05). The study has demonstrated the effectiveness of locally applied PRF after ITM surgery via clinical parameters and objective data. The quantitative analysis of CRP and ERS can be an effective parameter in determining the amount of inflammation after ITM surgery.

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.

Efficacy of the application of leukocyte and platelet-rich fibrin (L-PRF) on alveolar ridge preservation. A randomized controlled clinical trial

INTRODUCTION

Alveolar ridge preservation (ARP) is a well-defined treatment performed to reduce bone dimensional changes occurring during the healing of post-extraction sockets to allow for adequate implant placement. Leukocyte and platelet-rich fibrin (L-PRF) has been showing to potentially promote bone and tissue regeneration during wound healing. Therefore, the aim of this study is to evaluate its efficacy for ARP when applied to fresh extraction sockets, in comparison with spontaneous healing.

MATERIALS AND METHODS

Twenty-seven patients with hopeless non-molar teeth were treated. After randomization, fresh extraction sockets were either filled with L-PRF or allowed to heal spontaneously. CBCTs and intraoral scans were obtained immediately after extraction and at 4 months. Through superimposition of the obtained images, changes in the horizontal ridge width, height, buccal volume, and ridge contour changes were measured, as well as patient-reported outcome measures (PROM's).

RESULTS

The ridge dimensions changed similarly in both groups. Although less reduction occurred in the test group at 1 mm from the bone crest, differences were not statistically significant (p > 0.05). Application of L-PRF did not prevent reductions of ridge contours, neither in the linear vertical aspect nor in volumetric changes. There were no differences between groups in the need for bone regeneration when placing implants. Patients in both groups reported similar outcomes in terms of bleeding, pain, inflammation, and function at 1 and 4 weeks postoperatively.

CONCLUSION

Alveolar preservation with L-PRF neither minimized bone resorption occurring after tooth extraction in non-molar sites nor reduced the need for bone regeneration when placing implants. Furthermore, its use did not improve PROM's.

Fibrin clot and Leukocyte-rich platelet-rich fibrin show similar release kinetics and amount of growth factors: a pilot study

BACKGROUND

In knee arthroscopic surgery, fibrin clot (FC) and leukocyte-rich platelet-rich fibrin (L-PRF) may be used in augmentation for meniscal repair. Studies have investigated growth factors released from FC and L-PRF; however, it is difficult to compare FC and L-PRF between different studies. Direct comparison of growth factors that may support meniscal healing released from FC and L-PRF may be beneficial in deciding whether to use FC or L-PRF. If no significant difference is seen, the surgeon may decide to use FC which is easier to prepare compared to L-PRF. The purpose of this pilot study is to investigate the release amount and pattern of basic fibroblast growth factor (bFGF), platelet-derived growth factor AB (PDGF-AB), transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF), and stromal cell-derived factor 1 (SDF-1) from FC and L-PRF.

METHOD

Twenty milliliters (ml) of whole blood was collected from each of the four volunteers. Ten milliliters of whole blood was allocated for preparation of FC and 10 ml for L-PRF. FC and L-PRF were separately placed in 5 ml of culture media. Five milliliters of the culture media was sampled and refilled at 15 min, 1 day, 3 days, 1 week and 2 weeks. The collected culture was used to quantify bFGF, PDGF-AB, TGF-β1, VEGF, and SDF-1 release by Enzyme-linked immune-sorbent assay (ELISA). Mann-Whitney U test was performed to assess significance of differences in amount of each growth factor released between FC and L-PRF. Significance was accepted at P value less than 0.05.

RESULTS

At two weeks, the cumulative release of TGF-β1 was the highest among all the growth factors in both FC and L-PRF (FC:19,738.21 pg/ml, L-PRF: 16,229.79 pg/ml). PDGF-AB (FC: 2328 pg/ml, L-PRF 1513.57 pg/ml) had the second largest amount, followed by VEGF (FC: 702.06 pg/ml, L-PRF 595.99 pg/ml) and bFGF (FC: 23.48 pg/ml, L-PRF 18.2 pg/ml), which order was also common in both FC and L-PRF. No significant difference in final release amount and pattern was seen between FC and L-PRF.

CONCLUSION

The current pilot study showed that cumulative release amount and release pattern of PDGF-AB, VEGF, TGF-β1, and bFGF did not significantly differ between FC and L-PRF during the two weeks of observation.

Characterization of the Protein Corona of Three Chairside Hemoderivatives on Melt Electrowritten Polycaprolactone Scaffolds

In tissue engineering, the relationship between a biomaterial surface and the host's immune response during wound healing is crucial for tissue regeneration. Despite hemoderivative functionalization of biomaterials becoming a common tissue-engineering strategy for enhanced regeneration, the characteristics of the protein-biomaterial interface have not been fully elucidated. This study characterized the interface formed by the adsorbed proteins from various hemoderivatives with pristine and calcium phosphate (CaP)-coated polycaprolactone (PCL) melt electrowritten scaffolds. PCL scaffolds were fabricated by using melt electrospinning writing (MEW). Three hemoderivatives (pure platelet-rich plasma (P-PRP), leucocyte platelet-rich plasma (L-PRP) and injectable platelet-rich fibrin (i-PRF)) and total blood PLASMA (control) were prepared from ovine blood. Hemoderivatives were characterized via SEM/EDX, cross-linking assay, weight loss, pH and protein quantification. The interface between PCL/CaP and hemoderivative was examined via FTIR, XPS and electrophoresis. i-PRF/PCL-CaP (1653 cm^-1), PLASMA/PCL-CaP (1652 cm^-1) and i-PRF/PCL (1651 cm^-1) demonstrated a strong signal at the Amide I region. PLASMA and i-PRF presented similar N1s spectra, with most of the nitrogen involved in N-C=O bonds (≈400 eV). i-PRF resulted in higher adsorption of low molecular weight (LMW) proteins at 60 min, while PLASMA exhibited the lowest adsorption. L-PRP and P-PRP had a similar pattern of protein adsorption. The characteristics of biomaterial interfaces can be customized, thus creating a specific hemoderivative-defined layer on the PCL surface. i-PRF demonstrated a predominant adsorption of LMW proteins. Further investigation of hemoderivative functionalized biomaterials is required to identify the differential protein corona composition, and the resultant immune response and regenerative capacity.

Gingival phenotype changes after different periodontal plastic surgical techniques: a single-masked randomized controlled clinical trial

ABSTRACT: OBJECTIVES: Aim of this clinical study was to evaluate the effects on gingival thickness of three surgical techniques for root coverage: the coronally advanced flap (CAF) alone, with a sub-epithelial connective tissue graft (SCTG) or with leukocyte- and platelet-rich fibrin (L-PRF) membranes.

METHODS

Sixty patients with RT1 single maxillary gingival recession were treated with CAF + L-PRF (20 patients), CAF + SCTG (20 patients) or CAF alone (20 patients). At baseline and 6-month after treatment, gingival thickness (GT), keratinized tissue width (KT), gingival recession (GR), clinical attachment level (CAL), probing depth (PD), PROMs, and the aesthetic outcome were recorded.

RESULTS

CAF + SCTG and CAF + L-PRF groups showed a significantly greater mean GT increase than CAF alone (0.31 ± 0.10 mm) with no significant differences between CAF + SCTG (0.99 ± 0.02 mm) and CAF + L-PRF (0.92 ± 0.52 mm) groups (p = 0.55). CAF + SCTG was associated with a significantly greater KT gain (3.85 ± 1.04 mm), while in CAF + L-PRF (2.03 ± 0.53 mm) and CAF (1.50 ± 0.69 mm) groups, KT was not significantly increased. Both GR and CAL showed a significant within groups' improvement, without among-groups differences. No significant among-groups difference for the aesthetic outcome but greater discomfort and pain-killer consumption in CAF + SCTG group was detected.

CONCLUSION

All investigated surgical techniques produced significant GR reduction and CAL gain. GT was similarly augmented by CAF + L-PRF and CAF + SCTG techniques; however, the CAF + SCTG technique produced a more predictable KT and GT increase.

CLINICAL RELEVANCE

The results of our study suggest that the CAF + SCTG technique represents the most predictable method for the clinician to improve the gingival phenotype, an important factor for long term gingival margin stability.

Can Our Blood Help Ensure Antimicrobial and Anti-Inflammatory Properties in Oral and Maxillofacial Surgery?

In recent decades, the potential of PRF has been extensively studied. The number of studies about PRF has increased three times since the year 2012, but the full spectrum of its fundamental properties, such as antimicrobial and anti-inflammatory activity, is not clearly described. In oral and maxillofacial surgery, PRF is described in alveolar ridge preservation, orthognathic surgery, cleft lip and palate surgery, maxillary sinus augmentation, and dental implant placement as demonstrating favorable results and its clinical advantages. The structural complexity, inhomogeneous nature, and clotting ability of PRF make its antimicrobial effect evaluation complicated. Nevertheless, most of the used antimicrobial testing methods are based on antibacterial agent diffusion ability in culture media. Because the oral and maxillofacial region is the most frequent area of PRF application, its antimicrobial activity evaluation also prevails in the oral microbiome. PRF's biological potential is highly dependent on the specific preparation protocol and methodology used; it should be carefully prepared and kept under proper conditions to keep cellular content alive. PRF's influence on living cells demonstrates a stimulating effect on bone regeneration, and an angiogenetic effect, and it provides anti-inflammatory activity. According to analyzed studies, PRF demonstrated success in oral and maxillofacial surgery in various methods of application. Antibacterial and anti-inflammatory properties were proven by antibacterial activity against different bacterial species, sustained growth factor, sustained release, and cell activity on the material application. Accurately and correctly prepared PRF can ensure antibacterial and anti-inflammatory properties, and it can be a beneficial clinical tool in oral and maxillofacial surgery.

Evolution and Clinical Advances of Platelet-Rich Fibrin in Musculoskeletal Regeneration

Over the past few decades, various forms of platelet concentrates have evolved with significant clinical utility. The newer generation products, including leukocyte-platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF), have shown superior biological properties in musculoskeletal regeneration than the first-generation concentrates, such as platelet-rich plasma (PRP) and plasma rich in growth factors. These newer platelet concentrates have a complete matrix of physiological fibrin that acts as a scaffold with a three-dimensional (3D) architecture. Further, it facilitates intercellular signaling and migration, thereby promoting angiogenic, chondrogenic, and osteogenic activities. A-PRF with higher leukocyte inclusion possesses antimicrobial activity than the first generations. Due to the presence of enormous amounts of growth factors and anti-inflammatory cytokines that are released, A-PRF has the potential to replicate the various physiological and immunological factors of wound healing. In addition, there are more neutrophils, monocytes, and macrophages, all of which secrete essential chemotactic molecules. As a result, both L-PRF and A-PRF are used in the management of musculoskeletal conditions, such as chondral injuries, tendinopathies, tissue regeneration, and other sports-related injuries. In addition to this, its applications have been expanded to include the fields of reconstructive cosmetic surgery, wound healing in diabetic patients, and maxillofacial surgeries.

Autologous blood products: Usage and preparation protocols

FOCUSED CLINICAL QUESTION

What are the appropriate preparation protocols for autologous blood products to support their clinical utilization?

SUMMARY

Autologous blood products provide a unique clinical benefit. Their popularity among the professions is growing. However, as this is a rapidly evolving field, multiple modalities are presented within the literature. Frequently there is no demonstrated superiority to previous iterations. This brief review attempts to offer a concise chronology on their evolution, preparation, and where possible, evidence to support their clinical utilization.

CONCLUSIONS

The field of autologous blood products is expanding rapidly. These products appear to yield variable clinical benefits in specific indications. However, evidence supporting their universal application is scant, and the superiority of one formulation versus another is yet to be demonstrated.

Nonpharmacological Complementary Interventions for the Management of Pain after Third Molar Surgery: An Umbrella Review of Current Meta-Analyses

Objectives. To provide a nonbiased, complete assessment of what the evidence from meta-analyses informs us about complementary and nonpharmacological treatment options for the management of pain after third molar surgery, as well as highlight any discordancy, gaps, or lack of evidence among meta-analyses. Methods. The quality of the included systematic reviews was assessed using the ROBIS tool. Corrected covered area (CCA) was calculated for pairs of similar meta-analyses to identify the amount of overlap. Reviews that were the most recent, comprehensive, and had adequate quality were considered for analyses when reviews showed a high overlap. In cases with a low amount of overlap among meta-analyses, all eligible studies were included. Also, citation matrices were constructed to address overlap. A network meta-analytical approach was adopted to rank different interventions. Results. Ten meta-analyses were included for quantitative synthesis. The quantitative analysis revealed that platelet-rich fibrin and its derivatives as well as ozone therapy reduce early and late pain better than the other complementary interventions compared to control (no complementary intervention). Conclusions. Despite the shortcomings of included meta-analyses, consolidated evidence suggests that platelet-rich-fibrin and its derivatives as well as ozone therapy outperform the other nonpharmacological complementary interventions in reducing early and late postsurgical pain following third molar extraction. However, the results should be interpreted with caution due to an unclear risk of bias and lack of firm evidence in the included meta-analyses. Moreover, there is a need for a standard protocol for the application of nonpharmacological complementary interventions.

Combination of Advanced Platelet-Rich Fibrin and Pentoxifylline/Tocopherol as a Novel Preventive Option in Osteoradionecrosis: A Case Report

Osteoradionecrosis (ORN) of the jaws is an uncommon complication of radiation therapy that seriously affects the oral and maxillofacial region. Management of ORN is intrinsically difficult and treatment effects are unpredictable. ORN can be treated with pentoxifylline/tocopherol and autologous platelet concentrates to promote wound healing. Furthermore, the low speed of relative centrifugal forces platelet-rich fibrin (PRF + ) has been shown high efficacy for ORN. A 72-year-old male patient with history of radiation treatment for squamous cell carcinoma in the left side of the tongue. Six years after the treatment, his upper right first molar tooth (no. 16) was surgically extracted due to persistent pain. A few months following the extraction, intraoral examination showed gingival inflammation, and pain when palpation around the edentulous area of tooth no. 16. Radiological examination revealed retained root of 16 with radiolucent area and horizontal bone loss around upper right second molar tooth (no. 17). Pentoxifylline and tocopherol were given for a week before the surgical operation and were continued for 8 weeks after the operation. Retained roots of teeth no. 16 and 17 were removed and the sockets were debrided, the advanced PRF+ (A-PRF + ) membranes were placed followed by primary wound closure. Following 2 weeks of treatment, the mucosa healed and progressed to complete mucosal coverage at 2 months with no pathological findings or ORN progression. At 6-month follow-up, clinical and cone-beam computed tomography (CBCT) revealed no pathology. Our case demonstrates that the combination of pentoxifylline/tocopherol and the A-PRF+ surgical approach can be useful for wound healing and prevention of ORN.

Intraovarian Injection of Reconstituted Lyophilized Growth-Promoting Factor Extracted from Horse Blood Platelets (L-GFequina) Increases Oocytes Recovery and In Vitro Embryo Production in Holstein Cows

The purpose of this study was to determine the impact of intraovarian injections of a reconstituted lyophilized growth-promoting factor extracted from horse blood platelets (L-GFequina) on the number of ovarian follicles, the recovery of cumulus−oocyte complexes (COCs), and embryo development to the blastocyst stage in Holstein cows. Thus, 12 Holstein cows were assigned to three protocols. According to the number of punctured follicles in protocol 1, ovum pick-up (OPU) was conducted on days 6 and 14 of the cycle (day 0 = estrus). In protocol 2, every large follicle (more than 7 mm) was removed, and 1 mL of L-GFequina was intraovarian injected (day 0). Two days later, equine chorionic gonadotropin (eCG) was administered, and OPU sessions were conducted on days 6, 10, and 14. The same ovarian stimulation procedure as that in protocol 2 was performed in protocol 3, except that equine L-GFequina was not supplied. OPU was carried out on days 6 and 10 of the cycle. The results indicate that the intraovarian injection of L-GFequina significantly (p < 0.05) increased the number of OPU sessions per cycle, the recovery of cumulus−oocyte complexes (COCs), and the production of blastocysts. In conclusion, an intraovarian injection of L-GFequina can improves OPU-IVEP results in Holstein cows.

Suburethral implantation of autologous regenerative cells for female stress urinary incontinence management: Results of a pilot study

OBJECTIVES

To assess the feasibility and the safety of treating female stress urinary incontinence (SUI) with suburethral implantation of a mixture of the stromal vascular fraction from adipose tissue and leukocyte-and platelet-rich-fibrin.

METHODS

Patients with SUI were treated with a mixture of stromal vascular fraction and leukocyte-and platelet-rich fibrin. The stromal vascular fraction was obtained from enzymatic digestion of autologous adipose-tissue and added to an leukocyte-and platelet-rich-fibrin membrane. The mixture was transvaginally implanted into the suburethral area. A fraction of the Stromal vascular fraction sample was used for cellular characterization. Patients were followed for 9 months. Every 3 months, the patients were clinically evaluated with a cough- stress test and a validated-questionnaire. An MRI was performed preoperatively and 3 months after the procedure to assess tissue changes.

RESULTS

Ten patients received the surgical procedure. The validated-questionnaire revealed a subjective SUI improvement in nine patients 3 months after the operation and in seven patients 9 months after the operation. Eight, six, and four patients achieved a negative cough-stress test 3, 6 and 9 months post-injection, respectively. Flow cytometric analysis of stromal vascular fraction cell phenotypes revealed predominantly mesenchymal and endothelial cell heterogeneity. In total, we injected 0,18 × 10⁶ to 13,6 × 10⁶ cells. No adverse events were observed peri- or postoperatively.

CONCLUSION

These preliminary results suggest that the suburethral implantation of a combination of SVF and l-PRF is a feasible and safe modality for treating female SUI. However, evidence is lacking and further research are needed to clarify the respective roles of SVF and l-PRF in female SUI treatment.