Periodontitis is a chronic inflammatory disease that affects the supporting structures of the teeth, including the periodontal ligament and alveolar bone. It is highly prevalent, affecting 10–15% of adults, and has significant negative impacts on quality of life. Diabetes is a major risk factor for periodontitis, with susceptibility increased threefold in diabetic individuals. There is a clear relationship between hyperglycaemia and the severity of periodontitis. The mechanisms linking these conditions involve immune functioning, neutrophil activity, and cytokine biology. Emerging evidence suggests a two-way relationship between diabetes and periodontitis, with diabetes increasing periodontitis risk and periodontal inflammation negatively affecting glycaemic control. Diabetic individuals with severe periodontitis have increased risks of macroalbuminuria, end-stage renal disease, and cardiorenal mortality. Periodontitis treatment is associated with HbA1c reductions of approximately 0.4%. Oral and periodontal health should be promoted as integral components of diabetes management. The relationship between diabetes and periodontitis is complex, with both conditions influencing each other. Poorly controlled diabetes increases the risk of periodontitis and alveolar bone loss. Periodontitis can also worsen glycaemic control and increase the risk of diabetes complications. The management of diabetes requires attention to periodontal health, with periodontal therapy associated with improvements in glycaemic control. Oral health should be promoted as part of diabetes management, and collaboration between medical and dental teams is essential for the joint management of diabetes and periodontitis. The evidence supports the notion that effective periodontal treatment can improve metabolic control, although more research is needed to confirm these findings. The healthcare implications of the link between diabetes and periodontitis are significant, with poor oral health affecting morbidity rather than mortality. Oral diseases are highly prevalent and associated with significant morbidity, and their management is important for overall health. The management of diabetes and periodontitis requires a multidisciplinary approach, with periodontal therapy associated with improvements in glycaemic control. The importance of self-efficacy in managing both conditions is highlighted, with structured education programmes being effective in the management of diabetes and periodontitis. The dental team plays a crucial role in the management of diabetes, with periodontal screening and treatment being important components of diabetes care. The evidence supports the need for collaboration between medical and dental teams in the management of diabetes and periodontitis.Periodontitis is a chronic inflammatory disease that affects the supporting structures of the teeth, including the periodontal ligament and alveolar bone. It is highly prevalent, affecting 10–15% of adults, and has significant negative impacts on quality of life. Diabetes is a major risk factor for periodontitis, with susceptibility increased threefold in diabetic individuals. There is a clear relationship between hyperglycaemia and the severity of periodontitis. The mechanisms linking these conditions involve immune functioning, neutrophil activity, and cytokine biology. Emerging evidence suggests a two-way relationship between diabetes and periodontitis, with diabetes increasing periodontitis risk and periodontal inflammation negatively affecting glycaemic control. Diabetic individuals with severe periodontitis have increased risks of macroalbuminuria, end-stage renal disease, and cardiorenal mortality. Periodontitis treatment is associated with HbA1c reductions of approximately 0.4%. Oral and periodontal health should be promoted as integral components of diabetes management. The relationship between diabetes and periodontitis is complex, with both conditions influencing each other. Poorly controlled diabetes increases the risk of periodontitis and alveolar bone loss. Periodontitis can also worsen glycaemic control and increase the risk of diabetes complications. The management of diabetes requires attention to periodontal health, with periodontal therapy associated with improvements in glycaemic control. Oral health should be promoted as part of diabetes management, and collaboration between medical and dental teams is essential for the joint management of diabetes and periodontitis. The evidence supports the notion that effective periodontal treatment can improve metabolic control, although more research is needed to confirm these findings. The healthcare implications of the link between diabetes and periodontitis are significant, with poor oral health affecting morbidity rather than mortality. Oral diseases are highly prevalent and associated with significant morbidity, and their management is important for overall health. The management of diabetes and periodontitis requires a multidisciplinary approach, with periodontal therapy associated with improvements in glycaemic control. The importance of self-efficacy in managing both conditions is highlighted, with structured education programmes being effective in the management of diabetes and periodontitis. The dental team plays a crucial role in the management of diabetes, with periodontal screening and treatment being important components of diabetes care. The evidence supports the need for collaboration between medical and dental teams in the management of diabetes and periodontitis.