Source: « Le Chirurgien-Dentiste de France », n° 1821, 22 nov. 2018, Dr. Jean Sévalle
Chronic exposure to Porphyromonas Gingivalis, a pathogen involved in periodontitis, leads to brain inflammation, neurodegeneration and an increased production of amyloid peptide in mice.
Several studies on animal models as well as studies of brain samples from patients with Alzheimer's disease suggest a correlation between periodontitis and mild cognitive impairment. Specifically, the presence of Porphyromonas Gingivalis, in addition to Gingipain (one of the products of its metabolism), seems to be the cause. In a recent study, published in Plos One, Vladimir Ilieski and his colleagues tested this hypothesis by orally exposing mice to the pathogen and/or gingipain.
Based on pre-existing data and considering their animal findings, the authors concluded that there is a direct link between periodontitis and the increased risk of developing Alzheimer's disease. In fact, according to these animal findings, there is no doubt that exposure to the pathogen has consequences in terms of inflammation and neurodegeneration. In order to generalize their observation, the authors based their conclusions on the fact that there is a high incidence of periodontitis in the US population: about 50% of Americans are affected. They also pointed out, in the discussion, that several types of bacteria – some of which were involved in dental infections – have been found more frequently in the brains of Alzheimer’s patients, in comparison to “control groups”. These periodontitis/Alzheimer's disease correlations have been reported in numerous studies since the late 2000s and sometimes observed on very consistent cohorts of patients. Without a doubt, there is an obvious association between chronic inflammations and neurodegenerative pathologies (including Alzheimer's disease) and the scientific literature on this subject has been very abundant.
In conclusion, this study supports the prevailing hypothesis that chronic inflammation, wherever it occurs, contributes greatly to increasing the overall risk of developing Alzheimer's disease. However, as most scientists and doctors agree: Alzheimer's disease being so multifactorial, periodontitis alone cannot be the main cause.