The results of a study by Sara et al22 revealed that TLRs expression in chronic periodontitis significantly increased compared to healthy and gingivitis patients and TLR4 expression increased more than TLR2.22 Another study by Yamaguchi et al23 investigated the effect of gingival plaque on the production of inflammatory cytokines by inducing TLR2 and TLR4 in peripheral blood mononuclear cells. This evidence concerns the gene TLR4 and periodontitis.