## 3 Results  
In 1998, [PERSON] et al. [7]. developed platelet-rich plasma (PRP) as a breakthrough in the use of platelet preparations derived from blood with higher angiogenic or osteogenic potential than the clot found in the socket after extraction. He obtained it by centrifuging 400 to 450 mL of a patient's whole blood at 5600 RPM (revolutions per minute) with the addition of citrate phosphate dextrose (an anticoagulant). The previous procedure resulted in three layers of preparation, starting from the lowest: red blood cells, PRP (platelet-rich plasma, also called \"buffy coat\"), and PPP (platelet-poor plasma). After the PPP layer was collected, the remaining blood was centrifuged at 2400 RPM to properly separate the PRP from the red blood cells. To start the coagulation process, PRP must be mixed with 10%calcium chloride and bovine thrombin. Individual 10 mL syringes were used for mixing, with 6 mL of PRP, 1 mL of calcium chloride + thrombin and 1 mL of air collected as a mixing element. A proper PRP preparation with a gel consistency is formed after mixing in the syringe for 6 to 10 s.  
After extensive research, [PERSON] et al. [8], presented a modification to the PRP technique in 2013. According to the original concept, citrate phosphate dextrose is used as an anticoagulant, and calcium gluconate + bovine thrombin is used as a coagulant. After a 5-min centrifugation of 9 mL of the patient's blood at 900 RPM, three fractions are visible: red blood cells, buffy coat, and platelets with white blood cells. The top two fractions were collected and centrifuged again (1500 RPM, 15 min), after which this top layer of PPP is collected, leaving only 2 mL of PRP in the tube. When PRP is treated with 0.2 mL of 10% calcium gluconate, it forms a gel with 4.2 times the platelet concentration of peripheral blood. Both centrifuges use plastic tubes. [PERSON] et al. [9, 10] proposed another concept of an autologous blood derivative from the PRP family that accelerates the healing process, calling their product PRGF (Plasma Rich In Growth Factors). After a single 8-min centrifugation at 1850 RPM using 5 mL plastic tubes containing the anticoagulant sodium citrate, a fibrin clot was produced from the patient's blood. The centrifugation results in the three visible layers, starting from the bottom: a layer of red blood cells, a middle transitional layer called a buffy coat, and an upper layer of cell-free plasma, which includes two empirically defined layers: upper plasma with low-growth factors (PPGF), and lower plasma rich in growth factors (PRGF), which is collected from all centrifuged tubes and transferred to a pooled one, to which calcium chloride is added to induce clotting, and after 15 to 20 min PRGF gel is obtained. It is noteworthy that the authors do not use bovine thrombin (except from the previously mentioned modifications) for clot formation, and one of its salient features is the absence of both erythrocytes and leukocytes. According to the authors' findings, the absence of polynuclear neutrophils within the damaged tissues, which are the body's first line of defense against pathogens, may have a beneficial effect on healing. This is because they produce matrix metalloproteinases MMP-8 and MMP-9, which can impede tissue repair, as well as free radicals (active forms of oxygen and nitrogen), which can damage cells in surrounding tissues in addition to bacteria. The aforementioned family of PRP preparations is the first generation of platelet concentrates. Their main disadvantage is the need for coagulants and anticoagulants in the manufacturing process, which usually involves repeated centrifugation. In addition, the use of bovine thrombin can cause coagulopathies by stimulating the formation of antibodies against blood clotting components V and XI, as well as thrombin [11]. Therefore, researchers conducted additional studies to develop an autologous biomaterial that would not require the use of chemicals in the manufacturing process.