Title: The Bidirectional Relationship Between Diabetes Mellitus and Periodontal Disease: A Comprehensive Review
Authors: Ahmed Ishag,, Almoeiz Y. Hammad, Daris Adouma and Abdalla S. Aljabry
Volume: 10
Issue: 9
Pages: 123-135
Publication Date: 2026/09/28
Abstract:
Diabetes mellitus (DM) and periodontal disease are two highly prevalent chronic inflammatory conditions that exhibit a well-established bidirectional relationship. Diabetes increases the risk and severity of periodontal disease through mechanisms involving hyperglycemia-induced inflammation, oxidative stress, immune dysfunction, and advanced glycation end-product accumulation. Conversely, periodontitis adversely affects glycemic control through systemic dissemination of periodontal pathogens, inflammatory mediators, and subsequent insulin resistance. This review synthesizes current scientific evidence on the epidemiology, pathophysiology, and clinical implications of this bidirectional relationship. Periodontal disease has been recognized as the "sixth complication" of diabetes. Intervention studies demonstrate that non-surgical periodontal treatment can reduce glycated hemoglobin (HbA1c) levels by approximately 0.3-0.5 percentage points, a clinically significant improvement comparable to adding a second oral antidiabetic medication. Furthermore, periodontal therapy reduces systemic inflammatory markers, decreases diabetes-related healthcare costs, and may lower the risk of cardiovascular complications. Despite this robust evidence, periodontitis remains underdiagnosed and undertreated in the context of routine diabetes care. Integrated medical-dental collaboration, early screening, and timely periodontal intervention are essential to optimize outcomes for patients with diabetes and periodontal disease.