Several studies reported higher GCF levels of interleukin (il)‐1β (Becerik, Ozturk, Atmaca, Atilla, & Emingil, 2012; Gilowski, Wiench, Plocica, & Krzeminski, 2014; Konopka, Pietrzak, & Brzezinska‐Blaszczyk, 2012; Mogi et al., 1999; Orozco, Gemmell, Bickel, & Seymour, 2006; Toyman, Tuter, Kurtis, et al., 2015), interleukin‐6 (il‐6), interleukin‐8 (il‐8), and tumor necrosis factor (tnf)‐α (Becerik et al., 2012; Holzhausen et al., 2010; Konopka et al., 2012; Mogi et al., 1999; Zhang, Chen, Zhu, & Yan, 2016) in periodontitis patients than healthy persons. This evidence concerns the gene TNF and periodontitis.