RESUMEN
Platelet-rich fibrin (PRF) has been used increasingly in oral and maxillofacial surgery in recent years. The aim of this experimental study was to perform a mechanical evaluation of PRF from patients on warfarin. PRF samples were obtained from 21 patients on warfarin (mean INR 2.30 ± 0.89) and 21 non-anticoagulated patients (control; mean INR 1.08 ± 0.07). For the patients on warfarin, two experimental groups were formed based on the PRF centrifugation time: group A, 10 min (21 samples); group B, 18 min (20 samples). Control group samples (21 samples) were centrifuged for 10 min. Mechanical properties were evaluated by axial tensile test and suture retention test with an Instron 3345 universal testing machine. Mechanical parameters were compared between the groups using the Kruskal-Wallis test and Dunn's post-hoc test. Axial tensile values were similar in all groups. In the suture retention test, significantly lower values of deformation at maximum force were observed in the experimental group: group A (107.07 ± 25.05%) and group B (104.81 ± 16.79%) versus control (118.01 ± 17.61%) (P = 0.033). Moreover, maximum force was significantly lower in group A (0.17 ± 0.05 N) than in the control group (0.20 ± 0.06 N), while it was significantly higher in group B (0.22 ± 0.07 N) than in group A (P = 0.026). In conclusion, for patients on warfarin, the centrifugation time should be increased to 18 min in order to obtain PRF with superior performance.