Periodontal disease, tooth loss and dementia: Is there a link? A systematic review.

BACKGROUND: It has been suggested that dementia is caused by neuronal damage due to chronic inflammation from peripheral sources such as the oral cavity in periodontal disease. OBJECTIVE: The aim of our review was to assess the risk of dementia or cognitive impairment associated with chronic periodontitis and multiple tooth loss. MATERIALS AND METHODS: An extensive search of electronic databases of articles on the relation between periodontitis, tooth loss and dementia published on or before April 2016 was conducted. Experimental and human studies that provided a description consistent with multiple tooth loss, chronic periodontal disease and cognitive impairment obtained by validated methods were selected. The data extracted from the articles included study design, country of origin, sample size, methods used to assess periodontitis and cognition, average age at the baseline and number of years of follow-up. The Newcastle-Ottawa scale was used to assess the quality of human studies. RESULTS: The literature search yielded 756 articles which were independently screened, and 16 articles were included in the review. Four human studies reported an association of subsequent dementia with multiple tooth loss. One human study reported that chronic periodontal disease was associated with dementia. Eight experimental studies demonstrated an association between cognitive impairment and tooth loss. CONCLUSION: The literature on chronic periodontitis and multiple tooth loss as risk factors to dementia remains inconclusive. More randomised clinical trials on the association between periodontitis and dementia with uniform criteria for evaluation and diagnosis of periodontitis are warranted.