IL4 and periodontal disorder: To gain a more precise understanding of the role of cytokines in the relationship between carotid IMT and periodontal disease, future research is necessary to investigate the correlations between clinical parameters of periodontal disease and the balance between pro-inflammatory cytokines, such as IFN-γ, IL-17A, IL-1β, IL-2, IL-6, and IL-8; anti-inflammatory IL-10 and IL-4; and immunoregulatory cytokines, such as IL-27, IL-23, IL-22, IL-35, TGF-β, IL-13, VEGF, IL-5, and IL-29, involved in cardiovascular disease.