Effects of anti-diabetic medications on the teeth, oral soft and hard tissues, saliva, and implants: a scoping review

Diabetes mellitus (DM) is one of the world's most common non-communicable diseases. DM is a group of metabolic disorders in which blood glucose levels increase due to reduced insulin production or action, resulting in hyperglycemia. Various anti-diabetic medications, including insulin, metformin, glimepiride, glipizide, and thiazolidinedione, are used to control hyperglycemia in diabetic patients. These anti-diabetic medications have been shown to affect the gingiva, bone, fibroblast cells, pulpal tissues, dental stem cells, saliva, teeth, and oral microbiome. Metformin (a biguanide), insulin, and oral sulfonylureas (glipizide and glimepiride) have regenerative and host-modulating effects. Metformin and insulin can promote the growth of osteoblasts (bone-forming cells) and periodontal ligament fibroblasts and enhance the differentiation of mesenchymal stem cells to repair the lost periodontal tissues. Metformin is used in both systemic and local forms as a gel or scaffolds along with periodontal therapy (scaling and root planing) and surgical procedures to promote repair of periodontal tissues, alveolar bone defects, furcation defects, and osseointegration of dental implants. Although the effect of metformin on oral tissues is well established, the role of other anti-diabetic drugs on the oral and periodontal tissues is not comprehensively discussed. Thus, this review aims to discuss the positive and negative effects of various anti-diabetic medications on the oral cavity.