They say that flossing makes you live longer.

It doesn’t.

I mean, it will help keep your dental health in check, preventing tooth decay and the long-term issues that can come from that. But flossing alone will not extend your life.

Like with many other common beliefs, people tend to confuse causation and correlation.

Although flossing doesn’t cause you to live longer, people who floss regularly are also far likelier to have other healthy habits. They eat better, exercise more often, and are generally more health-conscious than people who do not floss.

Flossing is simply a small part of a correlated system of a healthier-than-average lifestyle.