Periodontitis is a common problem in patients with diabetes. The relationship between these 2 maladies appears bidirectional--insofar that the presence of one condition tends to promote the other, and that the meticulous management of either may assist treatment of the other. Both diabetes and periodontitis can stimulate the chronic release of proinflammatory cytokines that have a deleterious effect on periodontal tissues. The chronic systemic elevation of proinflammatory cytokines caused by periodontitis may even predispose individuals to the development of type 2 diabetes. Mechanical treatment of periodontitis (scaling and root planing), when combined with short-term administration of therapeutic levels of tetracycline-type antimicrobials, can temporarily improve glycemic control in diabetic patients, especially in those with advanced forms of periodontitis and poor glycemic control before treatment. The biochemical mechanisms suggested by these studies imply that other periodontal procedures designed to rid patients of periodontal pathogens may also improve the management of diabetes. Therefore, the authors suggest that periodontal patients with diabetes be treated in consultation with a periodontist (Figures 3a through 4b).