The association of periodontal microorganisms and Alzheimer’s disease: aliterature review

Abstract

The objective of this study was to conduct a literature review on the association between periodontal microorganisms and Alzheimer's Disease, using the PubMed and Lilacs databases with the descriptors "Alzheimer's disease", "periodontitis", "neurodegenerative diseases", "neuroinflammation", "periodontal pathogens", and "oral microbiome", from 2015 to 2025. After screening and applying eligibility criteria, 13 articles were selected for final analysis. The literature data indicate that periodontal microorganisms may contribute to the progression of Alzheimer's Disease (AD) through inflammatory and infectious mechanisms, reinforcing a possible bidirectional relationship between AD and periodontal disease (PD). Evidence suggests that oral infections can generate neuroinflammation and promote neurodegenerative processes, although genetic, environmental, and lifestyle factors also play a relevant role. The importance of oral health care for patients with cognitive decline is highlighted, as well as the need for more studies, especially longitudinal studies with larger samples, to confirm this association.

Keywords: Alzheimer's disease, Neurodegenerative disease, Neuroinflammation, Periodontitis, Periodontal pathogens, Oral microbiota.