Which bacteria is most associated with periodontitis in patients with diabetes mellitus?

Correct answer: C. Prevotella intermedia

• A. Aa is more associated with aggressive/localized periodontitis in younger, often non-diabetic patients.
• B. F. nucleatum is a bridging organism in periodontal biofilm but not the specific organism most associated with diabetic periodontitis in this context.
• C. Correct, per the source material — Prevotella intermedia has documented associations with periodontal disease in diabetic patients (hormonal/metabolic factors can favor its growth).
• D. T. denticola is part of the 'red complex' generally associated with chronic periodontitis but is not specifically highlighted as the diabetes-associated organism here.