Red-Complex Bacterial DNA in Carotid Atheroma of Dentate and Long-Term Edentulous Patients and Its Association With Mitochondrial DNA Copy Number

Objective: This study aimed to evaluate (i) the presence of red complex bacteria in carotid atheroma plaques of dentate and edentulous patients and (ii) the possible relationship between mitochondrial DNA copy number (mtDNA-cn), an indicator of mitochondrial function, and periodontal disease. Methods: The present study included 51 patients (30 dentate and 21 edentulous) scheduled for carotid endarterectomy. Subgingival, denture and atheroma plaques were analysed using polymerase chain reaction (PCR) for red complex bacteria. Atheroma plaque samples from all patients were examined using quantitative PCR for mtDNA-cn. Results: At least one bacterium was detected in both the subgingival and denture plaque. In the dentate group, the frequencies of Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola in atheroma plaques were 53.3%, 63.3% and 40%, respectively. In the edentulous group, these rates were 57.1%, 23.8% and 42.9%, respectively. The mtDNA-cn in atheroma plaque samples from the dentate group was significantly lower than that in edentulous patients (p = 0.049). Conclusion: This study demonstrated that red complex bacteria can be present in atheroma plaques, even in long-standing edentulous patients. Our findings suggest that existing periodontal infection in patients with teeth may be associated with decreased mtDNA-cn. Trial Registration: NCT07165054 (registration date: 09/03/2025): https://clinicaltrials.gov/study/NCT07165054?term=ay%C5%9Fe%20toraman&rank=5.