Objective Periodontal disease may predispose individuals to cardiovascular disease (CVD). Diabetes mellitus, especially in patients with severe periodontitis, increases the risk of CVD mortality. However, the outcomes of periodontal therapy vary among the different treatment modalities. We aim to investigate whether periodontal treatment could influence the occurrence of CVD in patients with type 2 diabetes and periodontal problems. Methods A retrospective cohort study was conducted based on a dataset released by Taiwan National Health Insurance (NHI). The dataset was composed of randomly sampled, newly diagnosed diabetic patients who received insurance benefits from 1999 to 2001; patients who were younger than 18 years of age or who already had CVD before 1999 were excluded. The NHI code was used to identify the treatments, including subgingival curettage and flap operations. The patients' demographic variables were matched using a 1:4 propensity score. All of the subjects were followed up until the onset of CVD, or December 31, 2011. A Cox proportional hazards regression analysis was performed to evaluate the effects of periodontal treatment on the rates of myocardial infarction, heart failure and stroke. Results Three thousand thirty-nine and 12,156 diabetic subjects were classified into the advanced periodontal treatment group and the non-advanced periodontal treatment group, respectively. The Cox proportional hazards analysis revealed that although the overall incidence of CVD was not significantly improved (Hazard ratio, HR 0.95; 95% CI 0.90-1.01), advanced periodontal treatment reduced the rates of myocardial infarction (HR 0.92; 95% CI 0.85-0.99) and heart failure (HR 0.60; 95% CI 0.45-0.80). There was no significance difference in the incidence of stroke (HR 0.95; 95% CI 0.85-1.06). Conclusion Advanced periodontal therapy lowers the rate of CVD, especially myocardial infarction and heart failure. Dental management has a beneficial effect on the health of patients with type 2 diabetes.