Many of the hundreds of species of bacteria living on your teeth build biofilm communities that become cavity- and gum-disease-causing plaque. Yet new research reveals that your mouth also contains some tooth-friendly bacteria that produce biofilm-busting enzymes. Researchers led by Hidenobu Senpuku of Japan’s National Institute of Infectious Diseases found that Streptococcus salivarius and several other saliva bacteria produce enzymes, including a fructosyltransferase and an exo-β-d-fructosidase, which inhibit biofilm formation in the mouth after sucrose consumption (Appl. Environ. Microbiol., DOI: 10.1128/AEM.02066-10). The team suggests that this inhibition occurs because the enzymes interfere with polysaccharide production by S. mutans, an infamous mouth bacterium known to be a culprit in cavity formation. After brushing your teeth, S. mutans likely uses sucrose-based polysaccharides to build biofilms that lead to plaque. Given the biofilm-thwarting properties of the enzymes, toothpaste makers may consider including them in future formulations.