Diabetes is a disorder in which insulin (a hormone that regulates blood sugar levels) is either not produced (Type I Diabetes), or the tissues of the body become resistant to it (Type II Diabetes), such that cells are unable to efficiently remove the sugar molecules and use them for energy. Gestational diabetes is a temporary, pregnancy-induced Type II Diabetes that resolves when the baby is delivered.
All three forms of diabetes have in common the fact that the blood is thicker (more viscous), and has difficulty passing through very small blood vessels such as those found in the eyes, extremities, and gums (gingiva). Immune cells may not be able to pass through thickened blood in order to get to a site of infection, so healing may be delayed.
Among the other complications of diabetes, a patient with the disorder may suffer from poor gingival health. In patients with periodontal disease (gum disease), a link has been established between control of the periodontal disease and ability for the patient to control their blood sugar levels (glycemic control). Specifically, a patient whose periodontal disease is controlled and actively managed to prevent chronic inflammation generally will have better control over their blood sugar.
Recent work has suggested that periodontal disease may be an independent cause of Type II Diabetes. To the extent that periodontal disease is preventable, a certain percentage of diabetes cases may be as well.