Periodontal diseases, common infectious diseases seen in humans, are characterized by gingival inflammation and a loss of connective tissue and bone around the roots of teeth, which leads to eventual tooth exfoliation. In the past decade, the association between periodontal diseases and the development of systemic diseases has received increasing attention. Periodontal pathogens and their products, as well as inflammatory mediators produced in periodontal tissues, can enter the bloodstream, thereby causing and/or contributing to the development of systemic diseases.