Evaluating growth-factor release in leukocyte- and platelet-rich fibrin, advanced platelet-rich fibrin, and injectable platelet-rich fibrin protocols: a narrative review

Since its introduction in 2001, multiple platelet-rich fibrin (PRF) centrifugation protocols have emerged, but the variations in growth factor release that result from these protocols remain unclear. This review aimed to evaluate growth factor release across three PRF protocols: leukocyte-PRF (L-PRF), advanced-PRF (A-PRF/+), and injectable-PRF (i-PRF). A comprehensive search was conducted using the MEDLINE and Embase databases, identifying 14 studies that met the inclusion criteria. Due to significant heterogeneity in study designs and methodologies, a meta-analysis was not feasible. However, our findings suggest that lower-speed centrifugation protocols, such as A-PRF/+ and i-PRF, tend to provide a more uniform cell distribution and sustain higher growth factor release over time compared to the conventional L-PRF protocol. Despite these observations, the current evidence is insufficient to draw definitive conclusions about the growth factor release levels among L-PRF, A-PRF/+, and i-PRF. Further well-designed, comparative studies are required to clarify these differences and establish optimal protocols for clinical use.