Re: "Clinical evaluation of a modified coronally advanced flap alone or in combination with a platelet-rich fibrin membrane for the treatment of adjacent multiple gingival recessions: a 6-month study".

Choukroun's platelet-rich fibrin (PRF) is a fibrin biomaterial with a specific composition, three-dimensional architecture, and associated biology. This letter highlights some key issues related to the use of this complex material during periodontal surgery. First, a reproducible protocol for the production of PRF membranes must be followed to control the quantity and quality of the fibrin matrix, leukocytes, platelets, and growth factors. Second, its use in periodontology must follow two principles founded on tissue-engineering basic rules and classical periodontal concepts. Using this two-principle safe protocol, the use of PRF in periodontal surgery leads to a significant improvement during the early healing phase and to a thick and stable final remodeled gingiva