Effects of Leukocyte-Platelet-Rich Fibrin (L–PRF) on Pain, Soft Tissue Healing, Growth Factors, and Cytokines after Third Molar Extraction: A Randomized, Split-Mouth, Double-Blinded Clinical Trial

Abstract

This study assessed the effects of leukocyte-platelet-rich fibrin (L–PRF) on soft tissue healing and the correlation with the local concentration of growth factors (GF) and cytokines in the dental socket of lower third molars. Forty lower-third molars (20 participants) were included in this randomized, double-blinded, split-mouth study. After extractions, randomized sides received alveolar filling with L–PRF on one side and a natural blood clot on the other side. The pain was assessed for up to seven days and soft tissue healing (Landry index) for 14 days post-extraction. Swabs were collected from the surgical sites for GF and cytokine assessment by flow luminometry. Participants reported lower postoperative pain on the sides grafted with L–PRF, which also presented increased tissue healing scores (p < 0.05). There were increased levels of all GFs and several cytokines at the L–PRF site at day one, while vascular endothelial growth factor (VEGF), IL–10, and IL1–RA remained higher throughout for seven days (p < 0.05). VEGF concentration at L–PRF sites correlated positively with the participants’ blood platelet content (ρ = 0.769). PDGF correlated negatively with pain experience on days 2 and 3, and positively with soft tissue healing scores, while FGFb presented a weak correlation with a reduction of pain on day 3. The use of L–PRF improves the soft tissue healing process and decreases postoperative pain after the third molar extractions, which correlates with an increase in the local concentration of growth factors such as PDGF and FGFb.