Recently, several researchers have demonstrated the association between periodontal disease and coronary artery disease (CAD). Therefore, we herein investigate the association between periodontal diseases and the existence of CAD among the study population who received both coronary angiography and dental examination. A total of 174 consecutive patients with dental examination including radiography and coronary angiography in the same hospitalization were recruited (64.5 +/- 10.3 years, M/F: 94/80). A dentist assessed severity of periodontal status markers (bleeding on probing, probing depth >or=6 mm, teeth lost, alveolar bone resorption >half of root length by radiography and smoking status). We divided these patients into two groups according to whether they had CAD (CAD group, n = 99) or not (non-CAD group, n = 75) according to the results of coronary angiography. The composite periodontal risk scores calculated from periodontal status markers were higher in the CAD group than in the non-CAD group (P = 0.02). The composite periodontal scores were higher in the CAD group of age <60 years old population (P = 0.03) and in the CAD group of patients with normal glucose tolerance (P = 0.04). However, the difference was not significant in the age >or=60 years old population or those with diabetes mellitus or impaired glucose tolerance. In all populations, hypertension, glucose tolerance, statin therapy, and composite of periodontal risk scores were associated with CAD. Multivariate analyses revealed statin therapy, glucose tolerance, and periodontal risk scores were independent and significant risk factors for CAD. Composite periodontal risk scores were independent and significant predictive factors for CAD.