Neuroinflammation, Alzheimer's disease and periodontal disease: Is there an association between the two processes?

Alzheimer's disease (AD) is a very common cause of dementia in developed countries and increases its prevalence progressively with age. AD etiopathogenesis is not yet understood. However, it is recognized that neuroinflammation plays a key role in its pathogenesis with the activation of microglia and the secretion of proinflammatory cytokines triggering irreversible neurodegenerative deterioration. This paper is a short review of the relationship between AD and periodontal disease (PD). Both processes may have common causes: both are inflammatory diseases and the prevalence and progression increases with ageing. However, we must consider that AD begins to develop many years before its clinical diagnosis. It is thought that in this prodromal period a connection could be established between both processes, both sustained by low intensity inflammation. There are several studies that relate both processes such as the possible systemic exposure to certain periodontopathogenic bacteria or the proinflammatory cytokines and other elements. It is argued that there are no modifiable factors such as age, or genetic factors, but that there are other factors that could be avoided, modified or controlled such as periodontal peripheral inflammation.