Diabetes and periodontitis are the most prevalent chronic diseases, and they influence each other's progression. Only a few studies have shown the association between diabetes and mild periodontitis. We aimed to investigate the relationship between well-controlled periodontitis and glycated hemoglobin (HbA1c) in patients with diabetes. This retrospective study investigated 150 Japanese patients with type 2 diabetes treated with supportive periodontal therapy (SPT). Medical histories of diabetes and periodontal therapy were collected, and a multiple linear regression analysis was performed to determine their association. The patients included 67 (44.7%) males and 83 (55.3%) females, with a mean age of 68.1 (standard deviation = 10.5) years. Forty-four (29.3%) patients were treated for diabetes, and the mean HbA1c was 6.7% (0.7). Oral status was 23.3 (5.1) for the number of teeth, 2.5 mm (0.4) for mean probing pocket depth (PPD), and 163.9 mm2 (181.3) for the periodontal inflamed surface area (PISA). The multiple regression analysis showed a significant association between mean PPD (β = 0.38, p = 0.03) and HbA1c in patients with mild diabetes but not in severe cases. These results suggest that the diagnostic indices for periodontitis used to assess the association between periodontitis and HbA1c would be determined based on the severity of periodontitis and type 2 diabetes.
Keywords: HbA1c; periodontal inflamed surface area; periodontitis; probing pocket depth; supportive periodontal therapy; type 2 diabetes mellitus.