There is no doubt that poor control of diabetes predisposes oral tissues to greater periodontal destruction. Poor metabolic control of diabetes makes the individual more susceptible to periodontal disease and can lead to a more aggressive periodontitis once it has developed. Those adults whose diabetes is controlled do not have any more destructive periodontitis than healthy individuals.
Conversely, untreated oral infections such as periodontitis impede metabolic control and impair the diabetic's ability to process or utilize insulin. Recent studies have presented evidence of a bidirectional adverse relationship between periodontal disease and diabetes mellitus, both type I and type II. Although diabetes is a metabolic disorder and periodontitis is an infectious disease, both diseases produce proinflammatory cytokines such as Interleukin-6. These inflammatory mediators impair the glucose-stimulated release of insulin from the pancreas.
Further, there is indication that a triangular interaction exists among obesity, type 2 diabetes and periodontal disease that is mediated by cytokine produced by fatty tissue and by infected gingival tissue.
Decreasing the bacterial load with periodontal therapy has been shown to stabilize glycemic control and reduce complications from unstable blood sugar levels. More research is needed to clearly identify the triangular pathway between obesity, periodontal disease and diabetes.
Kim, J.and Amar, S.: Periodontal disease and systemic conditions: a bidirectional relationship. Odontology.94(1):10-21, 2006.
Genco, R.J.: Opportunities for advancing dental hygiene research; Periodontal disease and association with diabetes mellitus and diabetes: clinical implications. Can J Dent Hyg. 43(5):217-223, 2009.