Relationship between periodontitis and diabetes - importance of a clinical study to prove the vicious cycle.

Periodontitis is regarded to have a close relationship to diabetes mellitus. In Japan, some cohort studies have indicated that there is a significant positive association of obesity plus metabolic syndrome with periodontal diseases. As such, an increasing number of studies suggest a relationship between periodontitis and diabetes, most of which are epidemiologic association. In this review, we have summarized the possible evidence of a relationship between periodontitis and diabetes. To date, little evidence has been reported to indicate that diabetes and/or glucose intolerance has in fact had a significant cause-effect relationship with periodontal disease. In this regard, it is important to directly uncover the relation, i.e., to prove the effect of therapeutic approaches to periodontitis upon mitigation of glycemic control in diabetic patients, which would be a direct evidence of its causal nature. Therefore a study should be undertaken to this effect.