© 2020 Verlag Klinisches Labor GmbH. All rights reserved.Background: A possible link between periodontal pathogenic bacteria and atherosclerosis may exist based on the inflammatory mechanisms initiated by bacteria found in periodontal lesions. Our aim was to investigate the pres-ence of DNA originating from T. denticola, C. rectus, T. forsythia, and P. gingivalis in the vascular tissue specimens obtained from patients who underwent surgery for arteriosclerotic vascular disease in this study. Methods: A total of 96 patients diagnosed with valvular heart disease due to atherosclerosis and 85 patients with advanced aortic valve stenosis due to rheumatic fever and had undergone aortic valve replacement were included as the study (PG) and the control groups (CG), respectively. Atheroma plaques and vascular tissue specimens were collected from PG and CG during cardiovascular surgical procedures. Revitalization of the lyophilized T. denticola, ATCC 35405; C. rectus, ATCC 33238; P. gingivalis, ATCC 33277 and T. forsythia, ATCC 43037 strains was performed according to the manufacturer's instructions. C. rectus, T. forsythia, and T. denticola DNA samples were analyzed using the one-step in-house PCR method. Results: In one (1.04%) and three (3.13%) out of 96 atherosclerotic PG tissue specimens, P. gingivalis and T. for-sythia DNA were detected, respectively. No T. denticola or C. rectus DNA was found in the study specimens. Peri-odontal pathogenic bacteria were not observed in 85 CG tissue specimens. There was no statistically significant difference between PG and CG for the presence of P. gingivalis and T. forsythia DNA using Fischer's Exact test (p > 0.05). Conclusions: In conclusion, with the case-control studies on a small scale such as in our study, it is not possible to determine a causality relationship between periodontal pathogenic bacteria and formation of atherosclerosis. Peri-odontal pathogenic bacteria may not be the only factor that causes inflammatory diseases associated with athero-sclerosis. Host response and inflammatory mechanisms may be affected by other factors such as ethnicity, dietary habits, nutritional availability, and lifestyle. Taken together, it is difficult to conclude a causal link between peri-odontal pathogenic bacteria and formation of atherosclerosis.