Currently there are over 740,000 patients with diabetes mellitus in the Netherlands, and this number will increase further in the coming years. Approximately 90% of patients has type 2 diabetes, a metabolic disorder that is often associated with obesity, hypertension and increased cholesterol levels. Treatment of diabetes mellitus is essential to reduce the risk of severe complications with irreversible organ damage in the long-term. Gingivitis and periodontitis are more common in patients with diabetes mellitus and are now also considered as complications of diabetes. Collaboration among healthcare professionals is important for effective diabetes care.