Polyphenols such as tannins in cocoa, coffee, tea, and many fruit juices may reduce the cariogenic potential of foods. In vitro experiments have shown that these polyphenolic compounds may interfere with glucosyltransferase activity of mutans streptococci, which may reduce plaque formation. In rat experiments, tea polyphenols reduced caries.

in “Sugars and dental caries”, Riva Touger-Decker and Cor van Loveren,
University of Medicine & Dentistry of New Jersey, School of Health Related Professions, New Jersey Dental School, Newark (RT-D), and the Academic Centre for Dentistry, Amsterdam (CvL).