Periodontitis is a chronic, dental-plaque induced inflammatory disease of the tooth-supporting tissues, resulting in a gradual loss of connective tissue attachment and alveolar bone. The interrelationship between diabetes mellitus and periodontitis has been studied for many years. At,present, there is strong evidence to suggest that the incidence and severity of periodontitis is influenced by the presence or absence of diabetes mellitus as well as by the degree of diabetes control by patients. Elevated blood glucose levels in poorly controlled diabetics result in an increase of protein glycosylation leading to amplified formation of so-called Advanced Glycation End products (AGE). AGEs are glucose products that have the ability to attract and stimulate inflammatory cells to produce inflammatory cytokines, elevating the risk of periodontal attachment and/or alveolar bone loss. Gram-negative periodontal infection significantly decreases glucose tolerance and can lead, like other types of inflammation, to an increase in the severity of diabetes. Thus, diabetes and periodontal disease form a system in which periodontitis is aggravated and metabolic control of blood glucose levels becomes more difficult. This in turn leads to mutual aggravation that results in a self-enforcing catabolic process, a vicious circle of inflammation, tissue destruction and insulin resistance.