This descriptive review synthesizes mechanistic and clinical evidence on the periodontal disease (PD)–atherosclerotic cardiovascular disease (ASCVD) axis to clarify how oral inflammation, bacterial translocation, immune dysregulation, and oxidative stress may influence vascular pathology and to identify where causal inference and interventional evidence remain insufficient. We searched PubMed, Web of Science, ScienceDirect, and Google Scholar for studies on microbial translocation, systemic inflammation, endothelial dysfunction, and interventional outcomes. Evidence supports a robust epidemiological association between PD and ASCVD; proposed mechanisms prominently involve Porphyromonas gingivalis-driven immune modulation and endothelial injury. Periodontal therapy consistently reduces inflammatory biomarkers and improves surrogate vascular measures, while effects on hard cardiovascular outcomes are suggestive but not definitive. Recognizing PD as a modifiable oral inflammatory condition may refine cardiovascular risk assessment and motivate integrated prevention, while future work should prioritize well-designed randomized trials with standardized PD/ASCVD phenotyping.