Effects of platelet rich fibrin and leukocyte (L-PRF) associated or not to a synthetic bone substitute on the healing of bone defects in rats calvaria

Platelet rich in Fibrin and leukocyte (L-PRF) is currently being used to promote bone regeneration and improve bone graft incorporation. This study evaluated the influence of L-PRF associated or not to a synthetic bone substitute (ReproBone &trade;) on bone repair in defects in rats calvaria. For this, 32 rats (Rattus norvegicus wistar) were divided into 4 groups (n = 8): C (control), PRF, REPRO and PRF-REPRO, and a critical size defect (DTC) of 5 mm diameter was created in the calvaria of the animals. In group C the defect was filled only with blood clot; in the PRF group the defects was filled with 0.02 mL of L-PRF; in the REPRO group the defect was filled with 0.02 mL of ReproBone &trade; ; In the PRF-REPRO Group the defect was filled with 0.02 mL ReproBone &trade; associated with L-PRF. After 30 days, the animals were euthanized and the bone healing was evaluated through microtomographic and histomorphometric analysis. The data were statistically analyzed (ANOVA, Tukey, p<0.05; for the analysis of the area of remaining particles in the groups with biomaterial Student\'s t test, p < 0.05, was carried out). In the Micro-CT evaluation, the groups with biomaterial presented statistically significant differences when compared to the Control and PRF groups, for the following parameters: Percentage bone volume (BV/TV: PRF-REPRO=22,14±7,23; REPRO=17,78±7,09); Bone surface density (BS/TV: PRF-REPRO=19,38±3,37; REPRO=18,63±6,14); Trabecular number (Tb.N: PRF-REPRO=4,39±0,77; REPRO=3,95±1,16); Trabecular thickness (Tb.Th: PRFREPRO= 0,05±0,01; REPRO=0,04±0,01); Trabecular separation (Tb.Sp: PRFREPRO=0,18±0,05; REPRO=0,20±0,09); Open porosity (Po.Op: RPFREPRO=77,71±7,32, REPRO=82,13±7,14) and Closed porosity (Po.Cl: PRFREPRO=0,63±0,30; REPRO=0,51±0,24). For the Total Porosity parameter, the difference was significant only between PRF-REPRO versus Control and PRF. The histomorphometric analysis showed a greater area of newly formed bone in the PRFREPRO (28.6 ± 9.21) and REPRO (19.13 ± 8.29) groups when compared to the C and PRF groups, and greater linear bone formation in the REPRO (1.89 ± 0.68) and PRF-REPRO (2.72 ± 0.60) groups. There were no statistical differences between the Control and PRF groups, and between REPRO and PRF-REPRO for none of the parameters evaluated. It was concluded that the groups with biomaterial presented the best results, and the addition of PRF to the biomaterial (PRF-REPRO group) presented the highest numerical values among all the groups evaluated, but without statistical differences when compared to the REPRO group. (AU)