## 5 CGF  
Concentrated Growth Factors (CGF) are derivatives of PRF and were developed by Sacco in 2006 [14; 37]. CGF is a fibrin-rich organic matrix obtained by centrifuging of the patient's venous blood, and is considered a third generation platelet enrichment that does not require any additional reagents to induce platelet activation as well as fibrin polymerization [38]. It contains growth factors, platelets, fibronectin, immune cells and CD34+ stem cells that play a vital role in regeneration processes, immunomodulatory responses, as well as having the ability to induce angiogenesis, chemotaxis and tissue remodeling, while being a matrix for cell migration [39; 40; 41; 42]. Due to the use of a different centrifugation speed, CGF contains a denser matrix that has more growth factors than both PRP and PRF, making it also more efficient at releasing them into the surrounding space, which can be especially useful in dentistry [43]. Among the numerous growth factors identified within CGF are platelet-derived growth factor (PDGF), transforming growth factor \(\beta\)-1 and 2 (TGF-\(\beta\)1 and TGF-\(\beta\)2), fibroblast growth factor (FGF), bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factor (VEGF), brain derived growth factor (BDGF), and insulin-like growth factor (IGF). They stimulate cell proliferation, matrix remodeling, and promote angiogenesis [5; 12; 21; 44]. It is noteworthy that CGF is associated with a sustained release of growth factors over 7-10 days, which can be used in aesthetic facial rejuvenation procedures, such as the treatment of wrinkles [45]. The ability to promote angiogenesis has applications in the regeneration of immature necrotic teeth in endodontics as an effective alternative to apexification [46]. It has been confirmed that CGF fibrous membrane is able to promote periodontal tissue regeneration involving hUCMSCs, which is achieved by upregulating the expression of TAZ and osteogenic differentiation-related genes [47]. The use of CGF together with a coronally advanced flap (CAF) leads to an increase in the amount of keratinized gingiva 6 months after maxillary recession coverage compared to a simple CAF procedure [48]. On the other hand, according to [PERSON] and [PERSON], CTG is superior to CGF in covering recessions, with CGF having a more positive effect on postoperative pain [49]. The biological properties of CGF, together with its viscosity and mechanical properties, allow it to improve the handling of other graft materials, promote wound healing, bone growth and maturation, as well as to stabilize bone grafts when used simultaneously [50]. Because of these properties, CGF has been widely used in jawbone regeneration procedures. Numerous studies have shown positive results with CGF as a biomaterial used in sinus lift procedures, which induces rapid and reliable bone formation [51; 52; 53]. CGF also induces osteoblastic differentiation promoting the early osseointegration of dental implants, leading to an increase in bone density around them [54]. There are some limitations to the use of CGF. First of all, platelet counts are affected by blood pH; changes in blood pH can interfere with cell proliferation. Furthermore, the time of CGF preparation and the volume of blood can affect the results [43; 45] (See Table 1).