Increased local concentrations of growth factors from leucocyte‐ and platelet‐rich fibrin do not translate into improved alveolar ridge preservation: An intra‐individual mechanistic randomized controlled trial

Aim Leucocyte- and platelet-rich fibrin (L-PRF) has been tested for enhancing alveolar ridge preservation (ARP), but little is known about the local release profile of growth factors (GF), and the clinical equipoise related to its efficacy remains. This study compared the patterns of GF release, early soft tissue healing, and alveolar ridge resorption following unassisted healing and L-PRF application in non-molar extraction sockets. Materials and Methods Atraumatic tooth extraction of two hopeless teeth per patient was followed by unassisted healing or L-PRF placement to fill the socket in 18 systemically healthy, non-smoking subjects. This intra-individual trial was powered to assess changes in horizontal alveolar ridge dimensions 1 mm below the crest of alveolar bone. GF concentrations in wound fluid were assessed with a multiplex assay at 6, 24, 72, and 168 h. Early healing was evaluated with the wound healing index and changes in soft tissue volumes on serial digital scans. Hard tissue changes were measured on superimposed CBCT images after 5 months of healing. Results L-PRF resulted in higher GF concentrations in wound fluid (WF) than in the control, but no differences in release patterns or time of peak were observed. No inter-group differences in early healing parameters were observed. Alveolar bone resorption was observed in both groups. No significant inter-group differences were observed in hard tissue healing 1, 3, or 5 mm apical to the original bone crest or in the ability to digitally plan a prosthetically guided implant with or without bone augmentation. Conclusions L-PRF increased the GF concentrations in WF of extraction sockets without shifting the pattern observed in unassisted healing, while the increased delivery did not translate into clinical benefits in early wound healing or ARP. The current findings question the assumption that increased local concentrations of GF by L-PRF translate into improved clinical outcomes. Additional definitive studies are needed to establish the benefits of L-PRF in ARP (ClinicalTrials.gov NCT03985033).