Scientists have discovered that bacteria, normally found in our mouths, is a tool that can be use to invade heart tissue, causing a dangerous and sometimes lethal infection of the heart known as endocarditis. S. mutans is a bacterium best known for causing cavities.

The study done raises the possibility of creating a screening tool – perhaps a swab of the cheek, or a spit test to gauge a dental patient’s vulnerability to the condition.

Normally, S. mutans normally confine themselves to the mouth, but sometimes, after a dental procedure or even after a vigorous bout of flossing, the bacteria can enter the bloodstream. Our immune system usually destroys them, but occasionally – within just a few seconds – they travel to the heart and colonize its tissue, especially heart valves. The bacteria can cause endocarditis – inflammation of heart valves – which can be deadly. Infection by S. mutans is a leading cause of the condition.