There are also some controversies in the literature regarding the role of IL-17 in the etiology and pathology of periodontal disease, with some studies not being able to prove an association between the presence of this cytokine and periodontal disease [16,17], while other authors have reported higher serum values of IL-17 in periodontally injured patients compared to a control group [18,19]. Here, IL17A is linked to periodontal disorder.