An in vitro study into three different PRF preparations for osteogenesis potential.

OBJECTIVE: To investigate the effect of Advanced Platelet-Rich Fibrin (A-PRF+), Leukocyte Platelet-Rich Fibrin (L-PRF), and injectable Platelet-Rich Fibrin (i-PRF) on osteogenesis of a human osteoblast-like cell line in vitro. BACKGROUND: Different PRF protocols are used in clinical dentistry in the last years. Recent literature documented the positive impact of PRF derivatives in vivo and in vitro, on different types of cells. However, hardly any literature comparing the new protocols for PRF (the A-PRF+ and i-PRF) with the original protocol of PRF (L-PRF) is present for osteoblast-like cells. MATERIALS AND METHODS: A-PRF+, L-PRF, and i-PRF were prepared from six male donors and pre-cultured with 10 mL culture medium for 6 days. 5 x 103  cells/ml osteoblasts from the osteoblast cell line (U2OS) were seeded and cultured either with conditioned medium derived from the different PRF conditions or with regular culture medium. At five different time points (0, 7, 14, 21, 28 days), the osteogenic capacity of the cells was assessed with Alizarin Red S to visualize mineralization. Also in these cells, the calcium concentration and alkaline phosphatase activity were investigated. Using qPCR, the expression of alkaline phosphatase, osteocalcin, osteonectin, ICAM-1, RUNX-2, and collagen 1a was assessed. RESULTS: In osteoblast-like cells cultured with conditioned medium, the A-PRF+ conditioned medium induced more mineralization and calcium production after 28 days of culturing compared with the control (p < .05). No significant differences were found in the extent of cell proliferation between the different conditions. RUNX-2 and osteonectin mRNA expression in the cells were lower in all PRF-stimulated cultures compared with control at different time points. The i-PRF-conditioned medium induced more ALP activity (p < .05) compared with control and osteoblasts-like cells differentiated more compared with osteoblasts cultured with L-PRF. CONCLUSIONS: The three PRF preparations seem to have the capacity to increase the osteogenic potential of osteoblast-like cells. A-PRF+ seems to have the highest potential for mineralization, while i-PRF seems to have the potential to enhance early cell differentiation.

Effects of L-PRF and A-PRF+ on periodontal fibroblasts in in vitro wound healing experiments.

OBJECTIVE: To determine whether leukocyte-platelet-rich fibrin (L-PRF) and advanced platelet-rich fibrin (A-PRF+) differ in their in vitro capacity to induce proliferation and migration of periodontal fibroblasts. BACKGROUND: L-PRF and A-PRF + are autologous materials used in periodontal regenerative surgery. They derive from blood from patients, but have different characteristics. The literature is controversial regarding the effects of the two PRF preparations on periodontal tissue fibroblasts. MATERIALS AND METHODS: L-PRF and A-PRF + membranes were prepared from eight patients and incubated in 3 mL of culture medium for 2 days. Gingival fibroblasts (G-F) and periodontal ligament fibroblast (PDL-F) primary cells were retrieved from 7 donors. These cells were pre-cultured for 1 day in wound healing experiment plates leaving a gap of 500 ± 50 µm in a concentration of 3.3 x 105 cells/mL. 70 µL of the cell suspension was placed in each half of the well. Thereafter, the pre-cultured L-PRF and A-PRF + supernatants were added to the experimental plates, and the fibroblasts were incubated for another 24 h. Medium alone (NEG) and fibroblast growth factor II (FGF) were used as controls. Subsequently, cell migration was registered for 24 h with live cell imaging in a time frame microscope at 5% CO2 in air at 37°C. Images were analyzed using ImageJ. Cell proliferation and cell viability were measured. RESULTS: L-PRF and A-PRF + induced higher cell proliferation than FGF and NEG. Both A-PRF + and L-PRF induced significant faster artificial wound closure than controls. Both PRF conditioned media induced faster cell migration in the initial phase (P < .01), but in the stoppage phase, the induced migration was higher for the A-PRF+, compared with L-PRF (P < .01). CONCLUSION: L-PRF and A-PRF + have a stimulatory effect on migration and proliferation of periodontal fibroblasts, and artificial wound closure was longer sustained by A-PRF + than L-PRF.

Use of Platelet-Rich Fibrin in the Treatment of Grade 2 Furcation Defects: Systematic Review and Meta-Analysis.

In periodontitis patients, furcation defects are crucial sites to regenerate due to their complex anatomy. Various modern surgical techniques and use of biomaterials have been suggested in the literature. Among all, platelet-rich fibrin (PRF) has potential in tissue regeneration thanks to its role in the release of growth factors. Therefore, the purpose of this study was to evaluate the beneficial effect of the addition of PRF to open flap debridement (OFD) or as an adjuvant to other biomaterials such as bone grafts in the treatment of grade 2 mandibular furcation defects. Systematic research was carried out on the databases Medline, Scopus, Embase, and Cochrane Library and registered on PROSPERO (CRD42020167662). According to the PICO guidelines by Cochrane, randomized trials and prospective non-randomized trials were evaluated, with a minimum follow-up period of 6 months. The inclusion criteria were the absence of systemic diseases, non-smoking patients, and a population aged from 18 to 65 years. Vertical pocket probing depth (PPD), vertical clinical attachment level (VCAL), and gingival recession (REC) were the primary outcomes. Vertical furcation depth (VFD), and the percentage of bone defect fill (%v-BDF) were considered as secondary outcomes. A meta-analysis of the primary and secondary outcomes was performed. Publication bias was assessed through a funnel plot. Eighty-four articles were initially extracted. Eight randomized clinical trials were analyzed according to the exclusion and inclusion criteria. The Quality assessment instrument (QAI) revealed four articles at low risk of bias, one at moderate, and three at high risk of bias. The metanalysis showed significant data regarding PPD, VCAL, VFD and %v-BDF in the comparison between PRF + OFD vs. OFD alone. The adjunct of PRF to a bone graft showed a significant difference for VCAL and a not statistically significant result for the other involved parameters. In conclusion, the adjunctive use of PRF to OFD seems to enhance the periodontal regeneration in the treatment of grade 2 furcation defects. The combination of PRF and bone graft did not show better clinical results, except for VCAL, although the amount of literature with low risk of bias is scarce. Further well-designed studies to evaluate the combination of these two materials are therefore needed.