The current scientific evidence for the bi-directional associations between oral health and diabetes is summarized. The universal biologic mechanisms and demographic and behavioral risk drivers underlying these associations in both directions are also described. Dysglycemia, even slightly elevated blood sugar levels, adversely affects oral health, manifesting itself in several oral diseases and conditions. In the opposite direction, any oral infection with its subsequent local and systemic inflammatory responses adversely affects blood glucose levels. Moreover, painful, mobile, or missing teeth may lead to intake of soft food items representing a sub-optimal diet and hence poor nutrition, and thereby contribute to incident type 2 diabetes or to poorer glucose control in existing diabetes. Treatment of inflammation related oral conditions, such as non-surgical periodontal treatment and extraction of infected teeth, can lead to a clinically significant decrease in blood glucose levels. Attention to infectious oral diseases and referral to dental care professionals for treatment can therefore be an important novel tool for medical care professionals in preventing and managing diabetes mellitus. Dental professionals can detect unrecognized potential dysglycemia and refer for medical examination. Such interprofessional, patient centered care may contribute to improved health, wellbeing, and quality of life in people with diabetes.