Influence of autologous platelet concentrates on early coagulation kinetics in regenerative dentistry: an ex vivo viscoelastic analysis

OBJECTIVES: Autologous platelet concentrates are widely used in regenerative dentistry, yet their direct effects on coagulation remain unclear. This study evaluated how platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and injectable PRF (iPRF) influence whole-blood clot formation using rotational thromboelastometry (ROTEM). METHODS: Whole blood from five healthy donors was analyzed ex vivo in a repeated-measures design. For each measurement, 300 µL of citrated whole blood was recalcified with 20 µL calcium chloride, followed by the addition of 20 µL of the respective platelet concentrate. ROTEM parameters included clotting time (CT), clot formation time (CFT), and alpha angle. Differences were analyzed using the Friedman test. RESULTS: Significant overall differences among conditions were observed for CT and alpha angle. Descriptively, PRF demonstrated the most pronounced effects on early coagulation kinetics, including markedly reduced CT values and increased alpha angles relative to control. PRP and iPRF showed more moderate effects. CONCLUSIONS: When added to whole blood, platelet concentrates differentially modified coagulation kinetics, primarily affecting clot initiation and early propagation. PRF produced the most pronounced acceleration, indicating that fibrin-containing preparations can markedly influence early clot formation in the surrounding blood. CLINICAL SIGNIFICANCE: Accelerated whole-blood clot formation, particularly with PRF, may support early hemostasis and earlier provisional fibrin-matrix establishment in ARP, GBR, and periodontal regeneration.