In vitro studies have shown that IL18 stimulation does not affect the cell cycle, apoptosis, and proliferation of healthy periodontal cells, but significantly promotes the production of proinflammatory cytokines by periodontal cells, and that IL18 may contribute to periodontal disease, either directly or indirectly, by promoting the migration of inflammatory cells (Yucel-Lindberg and Båge, 2013). This evidence concerns the gene IL18 and periodontal disorder.