Periodontitis is a common, chronic, inflammatory disease in which the supporting apparatus of the teeth is gradually destroyed, resulting in tooth mobility and tooth loss. Susceptibility to periodontitis is increased approximately three-fold in people with diabetes. Hyperglycemia leads to exacerbated tissue destruction and the clinical signs of periodontitis. There is evidence to support a two-way relationship between periodontitis and diabetes; not only does diabetes increase the risk for periodontitis, but periodontitis is associated with compromised glycemic control. Cooperation between health care teams would benefit the treatment of patients with diabetes and periodontitis.</p