This study aimed to determine whether a dental health education program would reduce cardiometabolic risk (obesity, hypertension, dyslipidemia, and hyperglycemia) in people with periodontitis. We used annual check-up data provided by the Japanese company's health insurance union. Of 182 male employees with cardiometabolic risk and periodontal pockets at baseline, 21 participants of the dental health education program and 21 non-participants matched for age, the presence of obesity, and periodontal pocket at baseline were allocated to the intervention (mean age, 53.3 ± 7.0) and the non-intervention groups (mean age, 52.9 ± 7.0), respectively. The program focused on self-removal of dental plaque with a toothbrush and interdental brush and comprised five sessions over 12 months. In the intervention group, waist circumference (cm) and diastolic blood pressure (mmHg) decreased from 88.4 ± 6.3 to 86.8 ± 6.3 and from 85.7 ± 8.2 to 82.6 ± 8.3, respectively (P < 0.05). Intergroup comparison showed significant improvement of systolic blood pressure (mmHg) in the intervention group (-3.7 ± 12.5) compared with the non-intervention group (4.0 ± 15.9) (P < 0.05) with no significant differences in the other parameters. The intervention group had a decrease in plaque accumulation and periodontitis symptoms, such as the depth of periodontal pocket and the presence of periodontal pocket and bleeding on probing, but an increase in the frequency of interdental brushing and duration of tooth brushing. Our findings show that dental self-care may improve blood pressure in people with cardiometabolic risk factors and periodontitis.