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 is aimed to investigate 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 (seven 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 (six studies; Ib, IIa, IIb) or its combination with biomaterials (six 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, with a high scientific level, showed that PRF (38 articles) 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.

Preliminary findings support that liquid PRF exhibits long-term analgesic effects in most patients with painful TMJ ID.

Background: Recent advances in 3D printing technology have enabled the emergence of new educational and clinical tools for medical professionals. This study provides an exemplary description of the fabrication of 3D-printed individualised patient models and assesses their educational value compared to cadaveric models in oral and maxillofacial surgery. Methods: A single-stage, controlled cohort study was conducted within the context of a curricular course. A patient's CT scan was segmented into a stereolithographic model and then printed using a fused filament 3D printer. These individualised patient models were implemented and compared against cadaveric models in a curricular oral surgery hands-on course. Students evaluated both models using a validated questionnaire. Additionally, a cost analysis for both models was carried out. P-values were calculated using the Mann-Whitney U test. Results: Thirty-eight fourth-year dental students participated in the study. Overall, significant differences between the two models were found in the student assessment. Whilst the cadaveric models achieved better results in the haptic feedback of the soft tissue, the 3D-printed individualised patient models were regarded significantly more realistic with regard to the anatomical correctness, the degree of freedom of movement and the operative simulation. At 3.46 € (compared to 6.51 €), the 3D-printed patient individualised models were exceptionally cost-efficient. Conclusions: 3D-printed patient individualised models presented a realistic alternative to cadaveric models in the undergraduate training of operational skills in oral and maxillofacial surgery. Whilst the 3D-printed individualised patient models received positive feedback from students, some aspects of the model leave room for improvement.

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.

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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.

Objective 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. Study design 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. Results 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. Conclusion 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.

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.