Diabetic Patients’ Awareness and Knowledge of the Association Between Apical Periodontitis and Diabetes Mellitus: A Cross-Sectional Study

Backgrounds/Objectives: The objective of this study was to evaluate diabetic patients’ knowledge and awareness regarding the association between diabetes mellitus and apical periodontitis and to examine demographic and clinical factors associated with knowledge and awareness scores. Methods: A cross-sectional study was conducted involving 504 patients with diabetes who attended the Obesity and Diabetes Research and Application Center between September 2025 and February 2026. Data regarding demographic characteristics, clinical status, and knowledge/awareness of the DM-apical periodontitis link were collected via a structured questionnaire. Statistical analyses were performed using the Kruskal–Wallis test followed by Dunn’s multiple comparison test, the Mann–Whitney U test, and Spearman’s correlation analysis (p < 0.05). Separate multiple linear regression models were also used to identify factors independently associated with knowledge and awareness scores. Results: The majority of participants were aged 51–80 (76.0%), female (59.1%) and had completed primary education (41.5%, n = 209). While 84% acknowledged the need for regular dental check-ups, 49.1% visited a dentist only for emergencies, and 85.9% lacked prior knowledge of apical periodontitis. Overall, 62.7% of participants recognized the importance of glycemic control for the healing of apical periodontitis, and 52.8% identified diabetes as a risk factor for apical periodontitis. A notable knowledge gap was observed regarding the reverse relationship: only 40.5% recognized that apical periodontitis may adversely affect diabetes control, whereas 53.0% reported having no idea. The mean knowledge score was 2.65 ± 1.97, and the mean awareness score was 26.57 ± 3.21. A strong positive correlation was found between knowledge and awareness scores (r = 0.605, p < 0.001). Knowledge and awareness scores differed significantly according to age and education level (p < 0.01 and p < 0.001, respectively). Knowledge and awareness scores also differed significantly according to dental-visit frequency and previous tooth-extraction history (p < 0.001). Gender and diabetes duration were not significantly associated with either knowledge or awareness scores (p > 0.05). In the multivariable analyses, education was the only factor that remained significantly associated with both knowledge and awareness scores after adjustment for the other variables included in the models. Conclusions: Important gaps were identified in diabetic patients’ knowledge and awareness regarding the association between apical periodontitis and diabetes mellitus, particularly concerning the potential relationship between apical periodontitis and glycemic control. Future studies should evaluate whether targeted educational interventions can improve endodontic-related health literacy and preventive dental-care behaviors.