The study’s findings are backed up by a multitude of research supporting the mechanisms. Researchers from the Institute of Psychiatry at London’s King’s College followed over 1050 adults for five years while tracking their oral health, as part of the Health, Aging and Body Composition (Health ABC) Study.

The test subjects were given comprehensive cognition tests and periodontal examinations at the beginning of the study and each year following for five years. Their degree of periodontal disease – or lack thereof – was calculated together with parameters of cognitive decline.

Gingivitis scores were calculated using the oral examinations based on levels of gum inflammation and sensitivity – established through probing. Cognitive scores were calculated using the Modified Mini-Mental State examination – also referred to as 3MS.

The research found that 90% of the test subjects had declining cognition through year five. The researchers then matched and removed risk factors such as education, sex, race, heart disease, age and depression from the calculation.

The research found that higher gingivitis inflammation at year two was strongly associated with cognitive declines of more than five points in the third to fifth years.

In their paper the researchers noted that, “Gingivitis is reversible, and periodontitis to some degree is preventable and controllable when manifest.”

Learn how to fight periodontal disease with oral probiotics.

Another study, this from the School of Dentistry at the University of Alabama, found among a study group of 9,853 adults over the age of 45 years old, that tooth loss was significantly associated with cognitive decline.

The research found that those who lost more than six teeth had greater cognitive decline than those with no tooth loss.

Periodontal disease is the leading cause for the loss of teeth.

While the association between cognition impairment and periodontal disease may seem mysterious, there is a solid basis for the mechanisms involved.

Numerous studies have linked periodontal disease with cerebrovascular disease and stroke. Cerebrovascular disease is the impairment of blood vessels that feed the brain cells. When these blood vessels become damaged or clogged, the brain can be starved of oxygen and essential nutrients.

Last year a meta-study review of clinical research by medical researchers from Greece’s Attikon University Hospital determined that 13 studies clearly proved the association between periodontal disease and a higher incidence of strokes and cerebrovascular disease.

Furthermore, medical scientists have established that pathogenic bacteria such as Streptococcus mutans that harbor within the gums will secrete their waste products into the bloodstream. These waste products are toxins that in turn damage blood vessels. Other research has suggested that some of these bacteria themselves may also escape into the bloodstream, causing sepsis and other infection-related inflammatory disorders.

A late 2011 study from the School of Dentistry at Italy’s University of Cagliari studied forty men between 20 years old and 40 years old. Half of the men had periodontal disease and the other half did not. The researchers tested the subjects for parameters indicating developing cardiovascular disease among both groups.

The research found that the periodontal disease patients had higher levels of inflammation-associated IL-2. This suggested to the researchers, “the existence of an early endothelial dysfunction in young adults with atypical periodontitis.”

In a study published in 2012, researchers from London’s University College School of Public Health combined mortality records with health surveys between 1995 through 2003. A sampling of nearly 13,000 people was used to calculate the cause of death and contributing factors.

This study found that those with tooth loss had three times the incidence of death related to having a stroke.

The association between stroke and cerebrovascular disease and cognition decline was made many years ago.

Periodontal disease is an inflammation of the gums produced by bacteria that colonize around the gums at the base and roots of the teeth. As the bacteria colonies grow, they form biofilms – which produce plaque. These bacteria biofilms secrete acids that break down the enamel of the teeth to form decay. These acids and other byproducts can also leak into the bloodstream, damaging the arteries that feed the brain.