Adjunctive Use of Platelet-Derived Concentrates (Platelet-Rich Plasma, Platelet-Rich Fibrin, Concentrated Growth Factor, Platelet-Poor Plasma) in Non-Surgical Periodontal Therapy: Current Evidence and Comparative Analysis

<b>Background</b>: Periodontitis is a multifactorial, chronic inflammatory disease that leads to progressive destruction of the periodontal apparatus. Despite the effectiveness of scaling and root planing (SRP), residual inflammation and limited regenerative potential justify the search for adjunctive biologic therapies. Platelet-derived concentrates, including platelet-rich plasma (PRP), platelet-rich fibrin (PRF), concentrated growth factors (CGF), and platelet-poor plasma (PPP), have gained attention as autologous sources of growth factors enhancing periodontal regeneration. <b>Aim</b>: This narrative review provides a comparative analysis of the biological mechanisms, preparation protocols, and clinical outcomes associated with the adjunctive use of platelet-derived concentrates in non-surgical periodontal therapy. <b>Methods</b>: A narrative literature review was conducted using English-language publications retrieved from PubMed and Google Scholar, covering studies published from 2012 onward. The search strategy was based on combinations of keywords related to platelet-derived concentrates and non-surgical periodontal therapy. In vitro, in vivo, and clinical studies, as well as relevant narrative, systematic, and umbrella reviews evaluating the adjunctive use of platelet-derived concentrates (PRP, PRF, CGF, and PPP) were considered. Studies focusing on biological mechanisms, preparation protocols, and clinical periodontal outcomes were included, whereas case reports, studies unrelated to periodontal therapy, and publications lacking relevant clinical or biological outcome data were excluded. <b>Results</b>: Most clinical studies reported improvements in probing depth reduction, clinical attachment level gain, and bleeding indices following adjunctive use of platelet-derived concentrates with SRP. PRF tended to demonstrate more consistent clinical outcomes compared to PRP, potentially related to its simplified preparation and sustained release of bioactive molecules. CGF showed promising osteogenic and angiogenic properties in preclinical and early clinical studies. PPP, although less extensively investigated, exhibited regenerative and antimicrobial potential in preliminary reports. <b>Conclusions</b>: Platelet-derived concentrates may serve as valuable adjuncts in non-surgical periodontal therapy; however, the current evidence is characterized by methodological heterogeneity and variable study quality. While PRF appears to yield more consistent clinical results, definitive conclusions regarding superiority among different platelet concentrates cannot be drawn. Further well-designed randomized controlled trials are required, particularly for CGF and PPP.