Poor Oral Health and Its Neurological Consequences: Mechanisms of Porphyromonas gingivalis Involvement in Cognitive Dysfunction

  • Ingar OlsenEmail author
  • Sim K. Singhrao
Microbiology (C Genco, Section Editor)
Part of the following topical collections:
  1. Topical Collection on Microbiology


Purpose of Review

There is an increasing body of evidence from epidemiology and laboratory investigations demonstrating periodontal disease as a risk factor for dementia. In particular, Porphyromonas gingivalis infections in animal models suggest causal associations with Alzheimer’s disease (AD). This review focuses on how P. gingivalis infections promote the incidence of functional loss in AD.

Recent Findings

The risk of the sporadic form of AD doubles when periodontitis persists for ten or more years. AD differs from other forms of dementia in that the clinical signs together with the presence of amyloid-beta (Aβ) plaques and neurofibrillary tangles must be present at autopsy. P. gingivalis oral infections in mice have demonstrated all of the characteristic pathological and clinical features of AD following infection of the brain.


Multiple factors (inflammation, Aβ oligomers, and bacterial factors) are likely to disrupt neuronal communication channels (synapses) as a plausible explanation for the functional loss.


Alzheimer’s disease Periodontitis Interaction P. gingivalis Virulence factors 


Compliance with Ethical Standards

Conflict of Interest

Ingar Olsen and Sim K. Singhrao each declare no conflict of interest.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.


Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

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Authors and Affiliations

  1. 1.Department of Oral Biology, Faculty of DentistryUniversity of OsloOsloNorway
  2. 2.Dementia and Neurodegenerative Diseases Research Group, Faculty of Clinical and Biomedical Sciences, School of DentistryUniversity of Central LancashirePrestonUK

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