Purpose To compare the release of platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF-I) and interleukin 1β (IL-1β) of plasma rich in growth factors (PRGF) and leucocyte platelet-rich fibrin (L-PRF) and to evaluate their biological implication in osteoblasts. Methods Blood from 3 healthy volunteers was processed into PRGF, immediate L-PRF (L-PRF 0ʹ) and L-PRF 30 min after collection (L-PRF-30ʹ) and a control group. Growth factors release were analyzed at 7 times by ELISA. Cell proliferation, collagen-I synthesis and alkaline phosphatase activity were assessed in primary cultures of human osteoblasts. Results A slower controlled release of IGF-I, VEGF and PDGF was observed in the PRGF group at day 14. A higher synthesis of type I collagen was also quantified in PRGF. L-PRF released significantly higher amounts of IL-1β, that was almost absent in the PRGF. Conclusions The addition of leukocytes dramatically increases the secretion of proinflammatory cytokines, which are likely to negatively influence the synthesis of type I collagen and alkaline phosphatase (ALP) by osteoblasts.

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Determine whether the implant loading time influences the marginal bone loss (MBL) that occurs in the different restorations on dental implants.Background: Different concepts of prosthetic loading have been proposed in literature. While the conventional loading (CL) protocol dictates to wait for a period of osseointegration of 3-4 to 6-8 months before loading the implant, the immediate loading (IL) protocol proposes to perform the implant loading within a period of no more than 1 week after its placement. Although there are several parameters to evaluate implant success, the evaluation of the radiographic changes of the MBL with standardized intraoral radiographic is the most used method in the literature to evaluate the success of the implant over time.Methods: A comprehensive search of the literature was conducted in the PubMed/MEDLINE (National Library of Medicine), Cochrane Library, Scopus and Web of Science electronic databases. The search strategy was done using the following terms: "dental implants", "loading protocols", "MBL".Conclusions: MBL is similar in both protocols, with no significant differences found in most published studies. IL has certain advantages such as reduced treatment time. However, good primary stability is needed to perform it. More studies are needed to establish clear conclusions.