There may be a link between how well you take care of your teeth and the progression of cognitive decline, according to new research published in the Journal of the American Geriatrics Society. This is a strong statement considering there isn’t enough definitive evidence to suggest one causes the other, but after conducting the first systematic review of studies focused on oral health and cognition, Duke University researchers think there’s something to it.

Dental care's impact on physical health is well-documented, and vice versa . Studies have found that your pearly whites can also be reflective of bone and mental health , as well as a person's risk of developing dementia, stroke , and coronary heart disease . But researchers aren't sure how exactly oral hygiene can impact cognitive health.

The researchers combed through 56 studies published between January 1993 and March 2013 that examined the relationship between oral health and change in cognitive health or dementia incidence — two of the most important areas of research as the older adult population continues to grow, with an estimated 98 million older persons living in the U.S. by the year 2060, according to the U.S. Department of Health and Human Services .

"Clinical evidence suggests that the frequency of oral health problems increases significantly in cognitively impaired older people, particularly those with dementia," lead author Dr. Bei Wu of Duke University's School of Nursing said in a statement . "In addition, many of the factors associated with poor oral health — such as poor nutrition and systemic diseases like diabetes and cardiovascular disease — are also associated with poor cognitive function."

Some of the studies analyzed found that dental health measures, such as the number of teeth, the number of cavities, and the presence of gum disease, were associated with an increased risk of cognitive decline or dementia. Which is interesting considering a 2013 study found gum disease bacteria in the brains of Alzheimer’s disease patients — but this study in no way proved that gum disease causes Alzheimer’s disease. It just acknowledged an association.

However, researchers contributing to the current review also noted that the findings based on the number of teeth or cavities are conflicting, and limited studies suggested that the dental conditions such as gingivitis are associated with cognitive decline. Similarly, researchers didn’t consistently find that cognitive decline was associated with greater loss of teeth or number of decayed teeth. However, it is likely that "methodological limitations play a major role in explaining the inconsistent findings," researchers wrote.

"There is not enough evidence to date to conclude that a causal association exists between cognitive function and oral health," Wu said. "For future research, we recommend that investigators gather data from larger and more population representative samples, use standard cognitive assessments and oral health measures, and use more sophisticated data analyses."

There might be a link between oral health and cognitive status, but as of now, it is unclear how they are related. More research is needed to better examine the linkages between the two.

Source: Wu B, Fillenbaum G, Plassman B. Association Between Oral Health and Cognitive Status: A Systematic Review. Journal of the American Geriatrics Society. 2016.