In a landmark series of studies conducted in the early 1990s involving Pima Indians from Arizona, it was concluded that diabetes increases the risk of developing destructive periodontitis by a factor of three. Age, sex, oral hygiene and other dental measures could not sufficiently explain the increase in this population, which has one of the highest incidence of Type 2 diabetes in the world. Those who had had diabetes for a long time experienced more advanced periodontitis, a response that correlates with development of other diabetes complications over time.
Recent studies now suggest there is a direct relationship between diabetes and periodontitis—those with diabetes have an increased incidence and severity compared to those without. While those with Type 1 and Type 2 diabetes are at risk, an individual’s glycaemic control, duration of diabetes and age appear to influence these manifestations to a greater extent that the type of diabetes.
While exact mechanisms of this relationship have not been clearly established, they could involve narrowing of the small blood vessels, increased connective tissue breakdown, alterations in bacterial plaque and defective white blood cells.
Vascular compromise, increased glucose levels in the periodontal tissues and decreased tissue oxygen may allow a selective overgrowth of harmful bacteria. Defective white blood cells means the body is unable to mount an effective immune response resulting in impaired connective tissue turnover. The cumulative effect of these different factors enables the disease to progress more quickly in people with poorly controlled diabetes than in other patients.
Happily, it has been found that a marked improvement of oral health may accompany effective glycaemic control of diabetes, and there are reports of a reduction in insulin requirements following periodontal therapy.