 The main objective of this study was to evaluate the matrix metalloproteinase MMP-8, and -9, tissue inhibitor of matrix metalloproteinase and interleukin-1beta levels in gingival crevicular fluid during the early and late stages of healing for gingival recession sites treated by coronally advanced flap plus platelet rich fibrin PRF compared to CAF plus connective tissue graft. As PRF consists of several growth factors, it may enhance the healing potential of soft tissues, the investigators hypothesized that using PRF in the treatment of gingival recessions might regulate inflammation and promote wound healing. 