Background: Platelet -rich fibrin (PRF) is a blood concentrate widely used in dentistry and in oral and maxillofacial surgery obtained through centrifugation. Recent studies have shown that the centrifugation protocols (CP) and the centrifuge machine affect the final characteristic of PRF. It is therefore essential to review the various CP outlined in the literature with the aim of increasing their reproducibility. The aim of this systematic review is to revise the existence of standardization of the latest CP. Methods: A systematic approach was used to perform the electronic literature search. Included studies were those performed in humans. The research question was formulated as follow: "Is the reporting of PRF's centrifugation protocols standardized?". The last electronic search was conducted in October 2020 in biomedical search engines. The results were gathered in table format, analyzed and discussed. Results: A total of 121 articles were found in the literature to be eligible for qualitative evaluation. The search gave as a result vertical and horizontal centrifugation protocols. Twenty-nine different CP and 16 different centrifuge machines were used to produce PRF. Fixed -angle rotors ranged from 33 degrees to 45 degrees and the radius -max from 85 to 130 mm. The protocols reported in RPM ranged from 700 to 3,500 rpm and the protocols reported in RCF (xg) ranged from 44 to 1,000 g. The treatment with the highest diversity of CPs [RPM/RCF (xg)/time] was the enhancement of soft tissue healing. Conclusions: It was found an absence of standardization in the reporting of the centrifugation protocols of PRF. In this regard, the present review involves a general discussion of all the principles that influence the final content of PRF and introduces the AR2T3 acronym. The purpose of AR2T3 is to increase the reproducibility of future PRF studies. The use of the acronym will allow the elaboration of meta -analyses and guidelines that are not yet available due to the heterogeneity of the data.

Objective: The study aims to identify the latest treatment protocols implementing platelet concentrates (PCs) to treat temporomandibular joint internal derangement (TMJ-ID) alone or in combination with arthroscopy/arthrocentesis. Background: Biosupplementation to treat TMJ-ID refers to the injection of an autologous product which possesses biological activity in the synovial joint, insofar as modulation of the inflammatory process, and can set the stage for tissue repair and/or tissue regeneration. PCs are increasingly used and tested, as an easily accessible biosupplement, for TMJ-ID. Methods: A systematic approach was used to perform the literature search. The study involves a presentation of recent data and a general discussion in the form of a narrative review regarding the biological characteristics and preparation protocols of PCs, the treatment protocols for TMJ-ID and clinical outcomes. Conclusions: The PCs described in the literature to treat TMJ-ID are platelet rich plasma (PRP), plasma rich in growth factors (PRGF), platelet-rich fibrin (PRF) and concentrated growth factors (CGF). All studies reported PCs as a beneficial therapeutic for TMJ-ID, in terms of arthralgia, joint noises and mandibular range of motion. Despite the biological differences among the various PCs, there exists similarities that could explain the reported benefits. The authors recommend clinicians the implementation of the acronym AR2T3 to standardize the reporting of PC preparations in future studies. Our findings suggest that non-surgical treatment through biosupplementation using PCs provides an alternative therapy or adjunct for painful TMJ-ID. The reduction in pain and dysfunction may avoid the need for TMJ surgery.

The aim of this study was to retrospectively review the midface and orbital floor fractures treated at our institution with regard to epidemiological aspects, surgical treatment options and postoperative complications and discuss this data with the current literature. One thousand five hundred and ninety-four patients with midface and orbital fractures treated at the Department of Oral, Cranio-Maxillofacial and Facial Plastic Surgery of the Goethe University Hospital in Frankfurt (Germany) between 2007 and 2017 were retrospectively reviewed. The patients were evaluated by age, gender, etiology, fracture pattern, defect size, surgical treatment and complications. The average patient age was 46.2 (± 20.8). Most fractures (37.5%) occurred in the age between 16 and 35. Seventy-two percent of patients were male while 28% were female. The most common cause of injury was physical assault (32.0%) followed by falls (30.8%) and traffic accidents (17.0%). The average orbital wall defect size was 297.9 mm2 (± 190.8 mm2). For orbital floor reconstruction polydioxanone sheets (0.15 mm 38.3%, 0.25 mm 36.2%, 0.5 mm 2.8%) were mainly used, followed by titanium meshes (11.5%). Reconstructions with the 0.15 mm polydioxanone sheets showed the least complications (p < 0.01, r = 0.15). Eighteen percent of patients who showed persistent symptoms and post-operative complications: 12.9% suffered from persistent hypoesthesia, 4.4% suffered from post-operative diplopia and 3.9% showed intra-orbital hematoma. Results of the clinical outcome in our patients show that 0.15 mm resorbable polydioxanone sheets leads to significantly less post-operative complications for orbital floor defects even for defects beyond the recommended 200 mm2.

Background The present study evaluated the cellular tissue reaction of two equine-derived collagen hemostatic sponges (E-CHS), which differed in thickness after pressing, over 30 days in vivo. The inflammatory response during physiological wound healing in sham-operated animals was used as control group. Material and methods First, the E-CHS was pressed by applying constant pressure (6.47 ± 0.85 N) for 2 min using a sterile stainless-steel cylinder until the material was uniformly flattened. Consequently, the original (E-CHS), the pressed (P-E-CHS), as well as the control group (CG; sham operation) were studied independently. The 3 groups were evaluated in vivo after subcutaneous implantation in Wistar rats during 3, 15, and 30 days. Histochemical and immunohistochemical methods provided observations of biomaterial degradation rate, cellular inflammatory response, and vascularization pattern. A derivative of human blood known as platelet-rich fibrin (PRF) was used as an ex vivo model to simulate the initial biomaterial-cell interaction. Segments of E-CHS and P-E-CHS were cultivated for 3 and 6 days with PRF, and the release of pro-inflammatory proteins was measured using ELISA. PRF cultivated alone was used as a control group. Results At day 3, the CG induced a statistically significant higher presence of monocytes/macrophages (CD68+), pro-inflammatory macrophages (M1; CCR7+), and pro-wound healing macrophages (M2; CD206+) compared to E-CHS and P-E-CHS. At the same time point, P-E-CHS induced a statistically significant higher presence of CD68+ cells compared to E-CHS. After 15 days, E-CHS was invaded by cells and vessels and showed a faster disintegration rate compared to P-E-CHS. On the contrary, cells and vessels were located only in the outer region of P-E-CHS and the biomaterial did not lose its structure and accordingly did not undergo disintegration. The experimental groups induced similar inflammatory reaction primarily with positive pro-inflammatory CD68+/CCR7+ macrophages and a low presence of multinucleated giant cells (MNGCs). At this time point, significantly lower CD68+/CCR7+ macrophages and no MNGCs were detected within the CG when compared to the experimental groups ( P < 0.05). After 30 days, E-CHS and P-E-CHS were fully degraded. All groups showed similar inflammatory reaction shifted to a higher presence CD206+ macrophages. A low number of CCR7+ MNGCs were still observable in the implantation bed of both experimental groups. In the ex vivo model, the cells and fibrin from PRF penetrated E-CHS. However, in the case of P-E-CHS, the cells and fibrin stayed on the surface and did not penetrate towards materials central regions. The cultivation of P-E-CHS with PRF induced a statically significant higher release of pro-inflammatory proteins compared to the CG and E-CHS after 3 days. Conclusion Altering the original presentation of a hemostatic sponge biomaterial by pressing modified the initial biomaterial-cell interaction, delayed the early biomaterial’s degradation rate, and altered the vascularization pattern. A pressed biomaterial seems to induce a higher inflammatory reaction at early time points. However, altering the biomaterial did not modify the polarization pattern of macrophages compared to physiologic wound healing. The ex vivo model using PRF was shown to be an effective model to simulate the initial biomaterial-cell interaction in vivo. Clinical relevance A pressed hemostatic sponge could be applied for guided tissue regeneration and guided bone regeneration. In that sense, within the limitations of this study, the results show that the same biomaterial may have two specific clinical indications.

Evaporation of phosphate species during thermal treatment (> 400°C) of calcium phosphates leads to the formation of an alkaline layer on their surface. The aim of this study was to evaluate the hypothe- sis that the biological response of thermally treated calcium phosphates is modified by the presence of such an alkaline layer on their surface. For this purpose, 0.125–0.180 mm α- and β-tricalcium phosphate (TCP) granules were obtained by crushing and size classification, with some being subjected to thermal treatment at 500°C. The four types of granules (α-TCP, β-TCP, α-TCP-500°C, and β-TCP-500°C) were implanted subcutaneously and orthotopically in rats. Sham operations served as control. Subcutaneously, α-TCP and β-TCP induced significantly more multinucleated giant cells (MNGCs) than calcined granules. Most of the induced MNGCs were TRAP-negative, CD-68 positive and cathepsin K- negative, reflecting a typical indication of a reaction with a foreign body. The vessel density was signifi- cantly higher in the α-TCP and β-TCP groups than it was in the α-TCP-500°C and β-TCP-500°C groups. In the femur model, β-TCP-500°C induced significantly more new bone formation than that induced by β-TCP. The granule size was also significantly larger in the β-TCP-500°C group, making it more resistant to degradation than β-TCP. The MNGC density was higher in the α-TCP and β-TCP groups than in the α-TCP-500°C and β-TCP-500°C groups, including cathepsin-positive, CD-68 positive, TRAP-positive and TRAP-negative MNGCs. In conclusion, this study confirms that the biological response of calcium phosphates was affected by the presence of an alkaline layer on their surface. Thermally-treated α-TCP and β-TCP granules produced significantly fewer MNGCs and were significantly less degraded than non-thermally-treated α-TCP and β-TCP granules. Thermally treating α-TCP and β-TCP granules shifts the reaction from a foreign body re- action towards a physiological reaction by downregulating the number of induced MNGCs and enhancing degradation resistance.

Abstract Aim This computational study aimed to evaluate the influence of the angle of the osteotomy when performing a high oblique sagittal osteotomy over the distribution of stress to the osteosynthesis plates and mandibular segments. Material and methods: For this purpose, a finite element analysis of different combinations was carried out based on the osteotomy angle and mandibular mobilization using Autodesk Inventor® resulting in a total of 72 simulations. To check the correlation between the osteotomy angles with respect to the tension in the mandibular structure in different mobilizations, a student t-test was used. Results: The results of the advancement mobilizations (2.5 mm to 5.5 mm) reported increasing values for tension in the probe of the fourth screw and in the probe of the plate surface as the osteotomy angle increased (p-value <10-8). The results of the setback mobilizations (−2.5 mm to −5.5 mm) show comparable values (p-value <10-8). The resulting contact surface between bone segments varies depending on the osteotomy angle, increasing 44.67% from 45° to 70° and decreasing 22.05% when the angle is reduced to 30°. Conclusion: The angle of the osteotomy is a very relevant parameter in the design of the studied mandibular osteotomy, since the distribution of the reported stresses is substantially susceptible to its variation.

Background The high-oblique sagittal osteotomy (HOSO) is an alternative to a bilateral sagittal split osteotomy (BSSO). Due to its novelty, there are no long-term studies which have focused on describing the incidence and type of complications encountered in the post-operative follow-up. The aim of this retrospective study is to analyze patients operated on with this surgical technique and the post-operative complications encountered. Patient and methods The electronic medical records of all patients treated with orthognathic surgery at the Department of Oral, Maxillofacial and Facial Plastic Surgery, University Hospital Frankfurt, Goethe University, Frankfurt, Germany, between the years 2009 and 2016 were retrospectively reviewed. Results A total of 116 patients fulfilled the inclusion criteria. The cases operated on with the standard osteosynthesis (X, Y, and straight) showed a complication rate of 36.37% ( n = 4/11). The cases operated on with the HOSO-dedicated plates (HOSO-DP) showed, in total, a complication rate of 6.67% ( n = 7/105). The most common post-operative complication resulting from both fixation methods was a reduction in mouth opening and TMJ pain for 4.3%. During the first years of performing the surgery (2009–211), a variety of standard plates had material failure causing non-union or pseudarthrosis. No cases of material failure were observed in the cases operated on with the HOSO-DP. The statistical results showed a highly significant dependence of a reduction in OP-time over the years, when the HOSO was performed without additional procedures ( R 2 > 0.83, P < 0.0015). Conclusion The rate of complications in the HOSO were shown to be comparable to the rate of complications from the BSSO reported in the literature. Moreover, the use of the ramus dedicated plate appears to provide enough stability to the bone segments, making the surgery safer. Clinical relevance The HOSO needs to be considered by surgeons as an alternative to BSSO. Once the use of the HOSO-DP was established, the rate of complications and the operation time reduced considerably.

Background: The feedback given to students plays an important role in their efficiency related to learning practical skills. In the present study, diverse feedback modalities have been investigated. Our hypothesis is that individualized and unsupervised video feedback can produce a similar learning experience as performing practical skills in an oral and maxillofacial surgery setting with conventional direct expert feedback (control group). Methods: This prospective, randomized, controlled, and blinded study compared direct expert feedback (DEF), individualized video feedback (IVF) and unsupervised video feedback (UVF). The participants were fourth-year dental students from University Goethe in Frankfurt. The students were assigned to one of the three feedback methods ( n = 20 per group) using simple randomization. All participants watched an instruction video for an interdental (‘Ernst’) ligature and periphery venous catheterization. Next, the students were video recorded performing the tasks by themselves (pre-test). Following this, every student received feedback using one of the above-mentioned feedback modalities. The participants then performed the same task again while being video recorded (post-test) to measure the acquired competence. Six weeks later, the students participated in an objective structured clinical examination (OSCE) to evaluate their long-term knowledge retention. All examiners were blinded regarding the students’ instructional approach and their affiliation in terms of the learning group. Results: For the interdental ligature, we found significant improvements in performance in each feedback modality group between the pre-test and post-test ( p <0.001). UVF had the strongest effect on performance time. The comparison between each group in the post-test showed no significant differences between the three groups. Conclusion: This study showed that IVF and UVF can be considered an alternative or adjunct to conventional methods ( i.e. DEF) when learning procedural skills in oral and maxillofacial surgery. However, DEF showed to be the most effective method of feedback and therefore preferable in teaching.

Objectives The aim of the present study was to characterize the cellular reaction to a xenogeneic resorbable collagen membrane of porcine origin using a subcutaneous implantation model in Wistar rats over 30 days. Materials and methods Ex vivo, liquid platelet-rich fibrin (PRF), a leukocyte and platelet-rich cell suspension, was used to evaluate the blood cell membrane interaction. The material was implanted subcutaneously in rats. Sham-operated rats without biomaterial displayed physiological wound healing (control group). Histological, immunohistological, and histomorphometric analyses were focused on the inflammatory pattern, vascularization rate, and degradation pattern. Results The membrane induced a large number of mononuclear cells over the observation period, including lymphocytes, macrophages, and fibroblasts. After 15 days, multinucleated giant cells (MNGCs) were observed on the biomaterial surface. Their number increased significantly, and they proceeded to the center of the biomaterial on day 30. These cells highly expressed CD-68, calcitonin receptor, and MMP-9, but not TRAP or integrin-ß3. Thus, the membrane lost its integrity and underwent disintegration as a consequence of the induction of MNGCs. The significant increase in MNGC number correlated with a high rate of vascularization, which was significantly higher than the control group. Physiological wound healing in the control group did not induce any MNGCs at any time point. Ex vivo blood cells from liquid-PRF did not penetrate the membrane. Conclusion The present study suggests a potential role for MNGCs in biomaterial degradation and questions whether it is beneficial to accept them in clinically approved biomaterials or focus on biomaterials that induce only mononuclear cells. Thus, further studies are necessary to identify the function of biomaterial-induced MNGCs. Clinical relevance Understanding the cellular reaction to biomaterials is essential to assess their suitability for specific clinical indications and outline the potential benefit of specific group of biomaterials in the respective clinical indications.

The permeability and inflammatory tissue reaction to Mucomaix® matrix (MM), a non- cross-linked collagen-based matrix was evaluated in both ex vivo and in vivo settings. Liquid platelet rich fibrin (PRF), a blood concentrate system, was used to assess its capacity to absorb human proteins and interact with blood cells ex vivo. In the in vivo aspect, 12 Wister rats had MM implanted subcutaneously, whereas another 12 rats (control) were sham-operated without biomaterial implantation. On days 3, 15 and 30, explantation was completed (four rats per time-point) to evaluate the tissue reactions to the matrix. Data collected were statistically analyzed using analysis of variance (ANOVA) and Tukey multiple comparisons tests (GraphPad Prism 8). The matrix absorbed the liquid PRF in the ex vivo study. Day 3 post-implantation revealed mild tissue inflammatory reaction with presence of mononuclear cells in the implantation site and on the biomaterial surface (mostly CD68-positive macrophages). The control group at this stage had more mononuclear cells than the test group. From day 15, multinucleated giant cells (MNGCs) were seen in the implantation site and the outer third of the matrix with marked increase on day 30 and spread to the matrix core. The presence of these CD68-positive MNGCs was associated with significant matrix vascularization. The matrix degraded significantly over the study period, but its core was still visible as of day 30 post-implantation. The high permeability and fast degradation properties of MM were highlighted.

Platelet-rich fibrin (PRF) is a blood concentrate derived from venous blood that is processed without anticoagulants by a one-step centrifugation process. This three-dimensional scaffold contains inflammatory cells and plasma proteins entrapped in a fibrin matrix. Liquid-PRF was developed based on the previously described low-speed centrifuge concept (LSCC), which allowed the introduction of a liquid-PRF formulation of fibrinogen and thrombin prior to its conversion to fibrin. Liquid-PRF was introduced to meet the clinical demand for combination with biomaterials in a clinically applicable and easy-to-use way. The aim of the present study was to evaluate, ex vivo, the interaction of the liquid-PRF constituents with five different collagen biomaterials by histological analyses. The results first demonstrated that large variability existed between the biomaterials investigated. Liquid-PRF was able to completely invade Mucograft® (MG; Geistlich Biomaterials, Wolhusen, Switzerland) and to partly invade Bio-Gide® (BG; Geistlich Biomaterials, Wolhusen, Switzerland) and Mucoderm® (MD; Botiss Biomaterials, Berlin, Germany), and Collprotect® (CP; Botiss Biomaterials, Berlin, Germany) showed only a superficial interaction. The BEGO® collagen membrane (BCM; BEGO Implant Systems) appeared to be completely free of liquid-PRF. These results were confirmed by the different cellular penetration and liquid-PRF absorption coefficient (PAC) values of the evaluated membranes. The present study demonstrates a system for loading biomaterials with a complex autologous cell system (liquid-PRF) in a relatively short period of time and in a clinically relevant manner. The combination of biomaterials with liquid-PRF may be clinically utilized to enhance the bioactivity of collagen-based biomaterials and may act as a biomaterial-based growth factor delivery system.

Different tissue engineering techniques are used to support rapid vascularisation.A novel technique is the use of platelet-rich fibrin (PRF), an autologous source of growth factors.This study was the first to investigate the influence of PRF matrices, isolated following different centrifugation protocols, on human dermal vascular endothelial cells (ECs) in mono-culture and co-culture with human primary fibroblasts (HFs) as an in vitro model for tissue regeneration.Focus was placed on vascular structure formation and growth factor release.HFs and ECs were cultivated with PRF prepared using a high (710 ×g) or low (44 ×g) relative centrifugation force (RCF) over 14 d.Immunofluorescence staining and immunohistochemistry were used to evaluate the microvascular formation.Cell culture supernatants were collected for evaluation of growth factor release.The results showed a PRF-mediated effect on the induction of angiogenesis in ECs.Microvessel-like structure formation was promoted when ECs were combined with low-RCF PRF as compared to high-RCF PRF or control group.The percentage of vascular lumen area was significantly higher in low-RCF PRF, especially at day 7, which coincided with statistically significantly higher growth factor [vascular endothelial factor (VEGF), transforming growth factor β1 (TGF-β1) and platelet derived growth factor (PDGF)] concentration measured in low-RCF PRF as compared to high-RCF PRF or control group.In conclusion, reducing the RCF according to the low-speed centrifugation concept (LSCC) resulted in increased growth factor release and angiogenic structure formation with EC mono-culture, suggesting that PRF may be a highly beneficial therapeutic tool for tissue engineering applications.

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.

Large bone defects have always been a big challenge. The use of bone marrow mononuclear cells (BMCs) combined with an osteoconductive scaffold has been proved a good alternative for the treatment of large bone defects. Another autologous source for tissue engineering is platelet rich fibrin (PRF). PRF is a blood concentrate system obtained through a one-step centrifugation. The generated 3D matrix of the PRF clot serves as a reservoir of growth factors. Those growth factors might support the regenerative response of BMC, and therefore the effect of PRF, centrifuged with either high medium (208 g) or low (60 g) relative centrifugation force (RCF) on BMCs was evaluated in vitro in the present study. The two PRF matrices obtained were initially characterized and compared to human serum. Significantly increased concentrations of insulin-like growth factor (IGF), soluble intercellular adhesion molecule-1 (sICAM1) and transforming growth factor (TGF)-beta were found in PRF compared to human serum whereas VEGF concentration was not significantly altered. A dose-response study revealed no further activation of BMC's metabolic activity, if concentration of both PRF matrices exceeded 10% (v/v). Effect of both PRF preparations [10%] on BMC was analyzed after 2, 7, and 14 days in comparison to human serum [10%]. Metabolic activity of BMC increased significantly in all groups on day 14. Furthermore, gene expression of matrix metalloproteinases (MMP)-2, -7, and -9 was significantly stimulated in BMC cultivated with the respective PRF matrices compared to human serum. Apoptotic activity of BMC incubated with PRF was not altered compared to BMC cultivated with serum. In conclusion, PRF could be used as a growth factor delivery system of autologous or allogeneic source with the capability of stimulating cells such as BMC.

OBJECTIVE:To evaluate the clinical benefits of liquid platelet-rich fibrin (PRF) in patients with temporomandibular joint (TMJ) pain and dysfunction. METHODS:Forty-eight TMJs in 37 patients with painful internal derangement (ID) (Wilkes' I-V) were included. Patients were injected with 1.5-2cc of PRF within the superior joint space at 2-week intervals. Pain and subjective dysfunction were recorded using a visual analog scale. Statistical analyses were done using the ANOVA test. RESULTS:Thirty-three of 48 TMJs (69%) showed significant reduction in pain at 8 weeks, and at 3, 6, and 12 months (Responders). Fifteen of 48 TMJs (31%) did not improve (Non-responders). The best Responders to liquid PRF injections were ID stages Wilkes' IV (78.5%) and V (100%), compared to Wilkes' I (0%), II (47%), and III (33%). A non-significant, but notable decrease in dysfunction was found. CONCLUSION:Preliminary findings support that liquid PRF exhibits long-term analgesic effects in most patients with painful TMJ ID.

Platelet-rich fibrin is a blood concentrate system used for soft tissue and bone tissue regeneration. In the last decade, platelet rich fibrin (PRF) has been widely used in different indication fields, particularly in oral and maxillofacial surgery. This review investigates the level of scientific evidence of published articles related to the use of PRF for bone and soft tissue regeneration in dentistry and maxillofacial surgery. An electronic literature research using the biomedical search engine “National Library of Medicine” (PubMed-MEDLINE) was performed in May 2017. A total of 392 articles were found, 72 of which were classified for each indication field. When comparing PRF with biomaterials vs biomaterial alone in sinus lift (5 studies; IIa), no statistically significant differences were detected. Socket preservation and ridge augmentation using PRF significantly enhanced new bone formation compared to healing without PRF (7 studies Ib, IIa, IIb). Reepithelialization and bone regeneration was achieved in 96 of 101 patients diagnosed with medication-related osteonecrosis of the jaw (5 studies, III). In periodontology, PRF alone (6 studies; Ib, IIa, IIb) or its combination with biomaterials (6 studies; Ib, IIa, IIb) significantly improved the pocket depth and attachment loss compared to a treatment without PRF. Over 70% of the patients were part of studies with a high level of scientific evidence (randomized and controlled prospective studies). This published evidence (38 articles), with a high scientific level, showed that PRF is a beneficial tool that significantly improves bone and soft tissue regeneration. However, the clinical community requires a standardization of PRF protocols to further examine the benefit of PRF in bone and soft tissue regeneration in reproducible studies, with a higher scientific level of evidence.

Aims: Platelet-rich fibrin (PRF) exists in both solid and fluid forms. The present study was the first to evaluate the influence of homogeneous pressure on the growth factor (GF) release in pressed PRF-matrices and plugs. Methods and Material: A solid PRF-matrix (208 g; 8 min) was pressed to obtain a plug, and a pressed PRF-matrix that are used in clinical application. The released exudates were evaluated compared to liquid PRF (60 g and 3 min). The VEGF, TGF-s1 and EGF release was quantified using ELISA. The fibrin structure and cellular components in solid PRF groups were evaluated histologically. Results: The pressed PRF-matrix and PRF-plug exhibited denser fibrin structure compared to the non-pressed PRF-matrix. On day 7, the PRF-plug and non-pressed PRF-matrix showed significantly higher release of VEGF, TGF-s1 and EGF compared to that of the pressed PRF-matrix. The accumulated VEGF concentration was significantly higher in the PRF-plug compared to that in the PRF-matrix and non-pressed PRF-matrix. The accumulated EGF and TGF-s1 concentrations over 10 days showed no statistically significant differences between the evaluated solid PRF groups. The exudates released TGF-s1 and EGF passively, that was only detectable in after 1 and 7 hours. Liquid PRF released significantly higher GFs than the exudates at all investigated time points. The early VEGF and EGF release in liquid PRF (1 hour to 1 day) was significantly higher than that in the solid PRF-matrices. On day 10, significantly higher accumulated GFs were detected in the solid PRF groups compared to those in the liquid PRF. Thus, the combination of both solid and liquid PRF is a potential tool to generate a clinically relevant system with sustained bioactivity. Conclusions: These results highlight the potential to influence the GFs release profile of solid PRF matrices by pressure and obtain a clinically applicable plug with significantly higher VEGF release, providing further understanding of the release profile of PRF matrices as a drug delivery system.