Maybe you’ve heard of those weirdly disturbing instances where tumors removed from a patient’s body have been found to contain hair and even teeth!

Well, this isn’t quite that strange. But it’s close.

A study performed in Finland found trace amounts of mouth bacteria present in brain clots of patients who suffered strokes. The takeaway? Good oral hygiene does more than prevent cavities. It could help to prevent a stroke.

This was what the scientists proposed after finding DNA traces of oral bacteria in samples of blood clots that had caused strokes.

Researchers from Tampere University in Finland analyzed several clot samples from 75 people who received emergency treatment for ischemic stroke when they attended Tampere University Hospital's Acute Stroke Unit. Of the study population, 69.3% were men and 30.7% were women.

The mean age of the patients was 66.9 years. None of the patients involved in the study had been treated with antibiotics or had experienced severe infections or septicemia during the stroke.

All the patients had undergone thrombectomies. These procedures remove blood clots by means of catheters conducted through arteries. The catheters can deploy stent retrievers and aspirators to reduce or remove the clot.

When they analyzed blood clots sampled in this way, the researchers found that 79% of the samples contained DNA from common oral bacteria. Most of the bacteria were of the Streptococcus mitis type, which belongs to a group that scientists call viridans streptococci.

The levels of the oral bacteria were much higher in the blood clot samples than they were in other samples that surgeons took from the same patients.

The team reports the findings in a recent Journal of the American Heart Association study.