Emerging evidence for associations between periodontitis and the development of Alzheimer’s disease

Abstract

Periodontal disease (PD) is an inflammatory disease affecting tooth-supporting tissues in which interaction of specific bacteria and the host’s immune responses play a pivotal role. The pathogenic bacteria associated with PD are a source of systemic inflammation as they have the ability to enter systemic circulation during everyday tasks such as brushing teeth and chewing food. Alzheimer’s disease (AD) is a form of dementia whereby inflammation is thought to play a key role in its pathogenesis and the risk of developing the disease increasing with age. The exact aetiology of the late-onset AD is unknown but peripheral infections are being considered as a potential risk factor.

Periodontitis: a potential risk factor for Alzheimer's disease

“…It is also possible that the longterm inflammatory burden on the systemic circulation causes neural degeneration. 65 The possibility of periodontitis in early and mid-life acting as a precursor to dementia in later life is increasingly being recognised. 51 In such cases the symptoms of dementia were not present in early and mid-life, so dementia impaired oral hygiene would be an unlikely causative factor for the periodontitis observed.…”

“…[85][86][87] Furthermore, the circum-ventricular organs are not protected by the blood-brain barrier, 88 and thus could potentially act as an entry portal for bacteria to reach other parts of the brain. 65 Microorganisms have been isolated more frequently from the brains of AD specimens than age-matched non-AD specimen's postmortem. Chlamydophila pneumoniae 89,90 and the spirochetes Treponema denticola 84 and Borrelia burgdorferi 91 have all been isolated from AD brain specimens postmortem, but not always from areas of AD neurodegeneration.…”

Differentiating Aging Among Adults With Down Syndrome and Comorbid Dementia or Psychopathology

“…There was an increased prevalence of dental concerns among this sample of adults with Down syndrome and dementia. Dental concerns are becoming an increasingly studied topic in the field of dementia in the typical aging population (Chalmers, Carter, & Spencer, 2003; Poole, Singhrao, Kesavalu, Curtis, & Crean, 2013; Poole, Singhrao, & Crean, 2014; Stein, Desrosiers, Donegan, Yepes, & Kryscio, 2007). The inflammation associated with dementia is being posited as a potential risk factor for the increased susceptibility to periodontal disease and dental concerns.…”