That's why it's important to focus on your oral hygiene and pay attention to what's going on with your teeth. One sign that your mouth isn't as healthy as it could be is if a calculus bridge forms.

That's why it's important to focus on your oral hygiene and pay attention to what's going on with your teeth. One sign that your mouth isn't as healthy as it could be is if a calculus bridge forms.

It shaves the calculus off very gently. So it's very different to the old-fashioned methods of scraping the teeth, which would take calculus away but would also scratch the tooth's surface.

The original version of this story appeared in Quanta Magazine. Calculus is a powerful mathematical tool. But for hundreds of years after its invention in the 17th century, it stood on a shaky ...