This thesis aims to highlight the important link between diabetes and dentistry. Many hormones help to regulate blood glucose levels. Diabetes mellitus has a very high global prevalence and exists in many forms, which require slightly different management strategies. Leading examples in the oral manifestations of diabetes mellitus include: periodontal disease, dento-alveolar abscess, xerostomia, sialosis, infections (viral, bacterial and fungal), dental caries and burning mouth syndrome. In conclusion, diabetes mellitus is a systemic disease encompassing various general medical and dental complications. Therefore, a good general medical practitioner - dentist relationship is crucial for effectively diagnosing and managing a diabetic patient.