In Vitro Evaluation of the Efficacy of Liquid Platelet‐Rich Fibrin ( PRF ) for Maintaining and Restoring Periodontal Ligament Cell Viability in Avulsed Teeth After 3 and 4 h of Extra‐Alveolar Dry Time

BACKGROUND/AIM: This in vitro study evaluated whether liquid platelet-rich fibrin could maintain or recover periodontal ligament cell viability in extracted human teeth after three and four hours of dry extra-alveolar time. MATERIAL AND METHODS: Sixty-six erupted third molars with complete root formation were allocated to four groups: three-hour dry control, three-hour dry storage followed by forty-five minutes in liquid platelet-rich fibrin, four-hour dry control, and four-hour dry storage followed by forty-five minutes in liquid platelet-rich fibrin. periodontal ligament cells were isolated by enzymatic digestion with type II collagenase and dispase. cell concentration and viability were determined by trypan blue exclusion in a neubauer chamber. HBSS- and milk-treated groups were not included. RESULTS: Liquid platelet-rich fibrin was associated with higher periodontal ligament cell viability after both dry-storage periods. cell concentration differed significantly in the four-hour comparison, whereas the three-hour concentration comparison was not statistically significant. CONCLUSIONS: Within the limitations of this in vitro study liquid platelet-rich fibrin was associated with greater recovery of viable periodontal ligament cells after prolonged dry storage. these findings do not establish superiority or equivalence to HBSS or milk and should be interpreted cautiously.