The aim of this comprehensive review was to evaluate comparative studies on horizontal and fixed-angle centrifugation methods for preparing platelet-rich fibrin (PRF). Furthermore, additional studies utilizing horizontal PRF (H-PRF) were systematically investigated. This overview review article offers deeper insights into the advantages of H-PRF when compared to fixed-angle methods across a wide range of regenerative medical and dental applications. A comprehensive search was conducted in PubMed and Web of Science up to December 5, 2024. Grey literature was also searched via Google Scholar for additional relevant studies, and reference lists of eligible studies were screened for further potential inclusion. All in vitro, in vivo, and clinical studies that utilized horizontal or swing-out centrifugation to prepare solid or liquid PRF, along with their subfractions such as the buffy coat, platelet-poor plasma (PPP), or heated variants like albumin gel or albumin gel with liquid PRF (Alb-PRF) as interventions, were included in this study. A total of 75 studies were included. Thirteen studies directly compared horizontal centrifugation to fixed-angle centrifugation for producing PRF, while the remaining 62 studies were non-comparative and focused on expanding the uses and clinical applications of H-PRF. These studies spanned categories such as cell concentrations, fibrin matrix structure, growth factor release, antibacterial and anti-inflammatory properties, and regenerative applications in bone, periodontal, cartilage, skin, hair, regenerative endodontics, corneal defect repair, wound healing, and soft tissue regeneration. Of the studies comparing horizontal to fixed-angle centrifugation, 84.6% favored horizontal centrifugation, while 15.4% found no difference. None of the studies favored fixed-angle centrifugation. Additionally, more optimized methods for concentrating liquid-PRF (C-PRF) using horizontal centrifugation and extending the resorption properties of PRF-ranging from 2 to 3 weeks to membranes lasting 4 months through an albumin denaturation process were-further discussed. Based on these findings, it remains logical to utilize H-PRF in clinical practice owing to the greater superiority in results from the majority of studies. Nevertheless, further comparative clinical studies are needed to support these findings. While the current evidence is limited and further clinical trials are warranted, several studies have now indicated that horizontal centrifugation, compared to fixed-angle, results in higher cell concentrations, more uniform cell distribution, and increased growth factor release. These advantages suggest that the use of H-PRF may lead to enhanced clinical outcomes when the application of PRF is indicated. Since horizontal centrifugation can also lead to better cell separation, it should also be the preferred method for producing C-PRF and Alb-PRF for clinical applications.
This systematic review aimed to evaluate all available evidence across all fields of medicine regarding the comparative effectiveness of platelet-rich plasma (PRP) versus injectable platelet-rich fibrin (i-PRF). A comprehensive search was conducted in PubMed, Scopus, and Web of Science up to September 30, 2024. Following a thorough screening process, studies were divided into in vitro, in vivo, and clinical studies based on their tissue/clinical indications. The initial search generated 2192 articles, of which 23 met the inclusion criteria. The findings demonstrated that i-PRF yielded higher platelet concentrations and offered a more sustained, long-term release of growth factors over time when compared to PRP. Overall, it was determined from in vitro studies that i-PRF significantly improved the activity of many cell types, including for skin, cartilage, periodontal, bone, soft tissue around dental implants, and pulp cells. In vivo outcomes also generally indicated that i-PRF outperformed PRP in cartilage and testicular regeneration. However, in orthodontic tooth movement, PRP was found to lead to superior short-term effects, while i-PRF showed more beneficial long-term effects. Clinical studies also found superior outcomes of i-PRF in skin regeneration, cartilage, and pulp regeneration. Outcomes regarding orthodontic tooth movement utilizing i-PRF or PRP remain controversial. In 72% of studies, i-PRF was found to lead to better outcomes across the various fields of medicine when compared to PRP, whereas 24% found no differences between the groups. Reasons and inconsistencies across the studies may be attributed to protocol differences and tissue types. Overall, additional clinical studies are needed with well-designed research and centrifugation protocols to better understand the regenerative potential of platelet concentrates in medicine. i-PRF offers a more sustained and prolonged release of growth factors and was favored in the majority of studies over PRP and should, therefore, be favored for the majority of medical and dental applications.
In order to evaluate the therapeutic advantages of various autologous platelet concentrates (APC) as a single biomaterial during alveolar ridge preservation (ARP), a systematic review with meta-analyses was conducted. PubMed, EMBASE, Web of Science, and Scopus were screened for randomized controlled trials (RCTs) that were released prior to 2024. The selected papers compared an APC with either unassisted healing (blood clot) or another biomaterial during ARP (third molars were not included). The outcome parameters included alveolar bone dimension alterations, soft tissue healing, and post-op pain intensity. The search yielded 35 papers (33 studies), one applying platelet-rich plasma (PRP), six using plasma rich in growth factors (PRGF), and 28 using leukocyte- and platelet-rich fibrin (L-PRF). These studies showed a large heterogeneity (e.g., outcome parameters, timing, surgical approach, and inclusion criteria), which hindered drawing strong conclusions. In most studies, however, ARP with PRP, PRGF, and L-PRF alone produced faster soft tissue healing, less post-extraction pain, less alveolar ridge resorption, more socket bone fill, and a higher bone density when compared to unassisted (spontaneous) healing. The ultimate benefit appears to be significantly influenced by the surgical approach. Limited literature exists comparing APC with other biomaterials for ARP, resulting in inconclusive data. APC application for ARP is a promising strategy to improve soft and hard tissue healing and reduce post-extraction pain.
This narrative review evaluates the existing literature on the clinical efficacy and safety of platelet-rich plasma (PRP) and plasma rich in growth factors (PRGFs) in extra-oral wound care, considering their potential benefits and drawbacks. The review specifically focuses on the impact of these treatments on patients' quality of life, pain management, treatment costs, recurrence rates, and potential complications. Given the extensive literature and diverse range of extra-oral wound types in which these autologous platelet concentrates have been applied, this narrative review focuses on the most frequently described wound types, including diabetic foot ulcers, venous leg ulcers, pressure ulcers, surgical wounds, and burns. The use of PRP has been reported in various medical specialties, with a low risk of adverse events. While there is a growing interest in the use of PRGF with promising results, the available literature on this topic is still limited. Only a few studies evaluated patients' perception of the treatment and the relationship between treatment costs and clinical outcomes. Data on recurrence rates and complications also vary across studies. In conclusion, PRP and PRGF show promise as alternatives or as adjunctive therapies to conventional treatments for various extra-oral wounds and ulcers, leading to reduced wound size and accelerated healing time but should be considered on a case-by-case basis, taking into account the type and severity of the wound.
Autologous platelet concentrates (APCs) applied alone or combined with other biomaterials are popular bioactive factors employed in regenerative medicine. The main biological rationale of using such products is to concentrate blood-derived growth factors and cells into the wound microenvironment to enhance the body's natural healing capacity. First-generation APC is represented by platelet-rich plasma (PRP). While different protocols have been documented for PRP preparation, they overall consist of two cycles of centrifugation and have important limitations related to the use of an anticoagulant first and an activator afterward, which may interfere with the natural healing process and the release of bioactive molecules. The second generation of platelet concentrates is represented by leukocyte and platelet-rich fibrin (L-PRF). L-PRF protocols involve a single centrifugation cycle and do not require the use of anticoagulants and activators, which makes the preparation more straight forward, less expensive, and eliminates potential risks associated with the use of activators. However, since no anticoagulant is employed, blood undergoes rapid clotting within the blood collection tube; hence, a timely management of L-PRF is crucial. This review provides an overview on the most documented protocols for APC preparations and critically discusses the main differences between first- and second-generation APCs in terms of cell content, protein release, and the formation of a 3D fibrin network. It appears evident that the inconsistency in reporting protocol parameters by most studies has contributed to conflicting conclusions regarding the efficacy of different APC formulations and has significantly limited the ability to interpret the results of individual clinical studies. In the future, the use of a standardized classification system, together with a detailed reporting on APC protocol parameters is warranted to make study outcomes comparable. This will also allow to clarify important aspects on the mechanism of action of APCs (like the role of leukocytes and centrifugation parameters) and to optimize the use of APCs in regenerative medicine.
This narrative review summarizes current knowledge on the use of autologous platelet concentrates (APCs) in esthetic medicine, with the goal of providing clinicians with reliable information for clinical practice. APCs contain platelets that release various growth factors with potential applications in facial and dermatologic treatments. This review examines several facial esthetic applications of APCs, including acne scarring, skin rejuvenation, melasma, vitiligo, stretchmarks, peri-orbital rejuvenation, peri-oral rejuvenation, hair regeneration and the volumizing effects of APC gels. A systematic review of literature databases (PubMed/MEDLINE) was conducted up to October 2023 to identify randomized controlled trials (RCTs) in the English language on APCs for facial rejuvenation and dermatology. A total of 96 articles were selected including those on platelet rich plasma (PRP), plasma-rich in growth factors (PRGF), and platelet-rich fibrin (PRF). Clinical recommendations gained from the reviews are provided. In summary, the use of APCs in facial esthetics is a promising yet relatively recent treatment approach. Overall, the majority of studies have focused on the use of PRP with positive outcomes. Only few studies have compared PRP versus PRF with all demonstrating superior outcomes using PRF. The existing studies have limitations including small sample sizes and lack of standardized assessment criteria. Future research should utilize well-designed RCTs, incorporating appropriate controls, such as split-face comparisons, and standardized protocols for APC usage, including optimal number of sessions, interval between sessions, and objective improvement scores. Nevertheless, the most recent formulations of platelet concentrates offer clinicians an ability to improve various clinical parameters and esthetic concerns.