摘要ABSTRACT The global increase in the aging population has significantly increased the prevalence of Alzheimer's disease(AD),placing substantial burdens on healthcare systems.Emerging evidence highlights a potential link between AD and peri-odontal disease(PD),implicating Porphyromonas gingivalis(Pg)as a key microbial driver.In this review,we explore the bidirectional relationship between AD and PD through epidemiological evidence,Pg dissemination along the oral-brain axis,virulence factor-driven neuroinflammation and blood-brain barrier dysfunction,as well as aging-mediated sus-ceptibility and therapeutic implications.Available data suggest that Pg and its virulence factors reach the central ner-vous system through hematogenous dissemination and neural pathways.Once in the brain,these agents trigger micro-glial and astrocytic activation,fostering chronic neuroinflammation and accelerating amyloid-β deposition and tau hyperphosphorylation,two hallmark pathologies of AD.Aging may further amplify host susceptibility and inflammatory responses.Although gingipain inhibitors have demonstrated neuroprotective potential in preclinical models,their clin-ical applications remain limited.Importantly,most existing evidence is based on preclinical and epidemiological studies and remains to be validated in well-designed human studies.Future studies integrating multi-omics ap-proaches and precision medicine strategies are warranted to identify individuals at high risk and develop targeted in-terventions aimed at mitigating Pg-associated neurodegenerative processes and reducing the AD burden.