Figure 5.

Schematic representation of PRF formation during centrifugation and the resulting platelet accumulation in specific regions of PRF matrices. (a) According to the conventional and widely-accepted concept, specific gravity-dependent fractionation precedes coagulation almost homogenously. Thus, the gradation of platelet density is preserved in PRF matrices. (b) In our proposed concept, coagulation occurs from the outside, a little earlier than fractionation. Thus, platelets entrapped loosely in gradually clotting PRF matrices are accumulated in the distal peripheral region. This proposed mechanism is consistent with our observations.