Contribution of aging oral microbiota in getting neurodegenerative diseases

Abstract

Nowadays aging-related neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease are as important as infectious diseases for human communities. 60–80% of dementia cases are related to Alzheimer's disease while only 2–3% of cases are associated with Parkinson's disease. Oral bacteria produce some chemical compounds such as volatile sulfur compounds and therefore are responsible for halitosis (malodor). This is while most of the cases (80–90%) of halitosis caused following the production of volatile sulfur compounds in the oral cavity. Some periodontal pathogens such as Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Prevotella gingivalis are detectable in Alzheimer's patients. On the other hand, Prevotella genus members, (e.g., P. intermedia, P. nigrescens, and P. melaninogenica) increase in Parkinson's disease patients, and most likely, it is associated with a reduction in hygiene oral care. Although many aspects of these diseases are still unknown, we have studied the Alzheimer's disease and Parkinson's disease diseases and also the role of oral microbiota infections in these diseases in older persons.