Different approaches to enhance healing of hard or soft tissues include the use of cytokines and growth factors to modify cellular behaviour. Numerous growth factors are found in autologous blood concentrates - platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). Enamel matrix derivative (EMD) may improve tissue healing via amelogenins. Bilayered collagen matrix (CM) is used for soft tissue augmentation. The aim of the present study was to assess potential benefits of PRP, PRF and EMD in combination with bilayered collagen matrix or CM alone in treatment of oral mucosal defects in rabbits. Twenty-seven New Zealand white rabbits were included in this randomized controlled trial. Artificial oral mucosal defects were treated with one of these five approaches: PRP+CM, PRF+CM, EMD+CM, CM alone, or left untreated as a negative control - CO. The animals were euthanized 1 day, 7 days, or 28 days after surgery and necropsies were harvested. Histological and molecular biological analyses were performed. All defects were healed by day 28. No differences between PRP+CM, PRF+CM, CM alone and CO groups were recorded at any time point. Slower angiogenesis and a higher presence of inflammatory infiltrate were observed in the EMD+CM group 28 days after surgery. Molecular biological analyses did not reveal any statistically significant changes. In conclusion, no improvement in mucosal healing of wounds covered with a collagen membrane and PRP, PRF, or EMD was observed, compared with CM alone or untreated controls.
