Most people have heard of cavity-causing bacteria before—especially Streptococcus mutans, which has long been considered one of the biggest contributors to tooth decay. But recent research suggests the story may be more complicated than previously understood.

In a study published by researchers at the University of Pennsylvania, scientists identified another bacterial species, S. sputigena, that appears to work alongside Streptococcus mutans to make cavities more aggressive.

While this discovery doesn’t change the basics of good oral hygiene, it offers an exciting new perspective on how cavities develop and why preventive care remains so important.