Tooth brushing is good for your mouth. But it may not be good for the heart in people at risk for cardiac infections. Here’s why: Brushing dislodges bacteria that can enter your bloodstream through damaged gums.

Once there, they can colonize your heart valves, which have little resistance to infection. This doesn’t happen often, but a study published in the journal Circulation suggests this threat should be taken seriously.

Researchers recruited almost three-hundred dental patients, all of whom needed a tooth extracted. They were assigned to three groups.

Patients in two groups had the tooth pulled. One group received an antibiotic first, the other got a placebo. Patients in the third group simply brushed their teeth. None of their teeth were pulled.

Blood samples were taken before, during and after the extractions or brushings and analyzed for mouth-dwelling bacteria known to infect heart valves.

About one-quarter of the patients who brushed had one or more target species in their blood. The bacteria showed up more than twice as often… about sixty percent of the time… in patients who received the placebo and had a tooth pulled.

But researchers were a little surprised that brushing… something many people do every day… sets so many microbes loose.

Of course, brushing prevents far more health problems than it ever starts. But if you’re at risk for heart-valve infections, talk to your doctor AND your dentist about how to avoid dental disease. We’re not just flapping our gums here.