I am a dental hygienist and our local dental society doesn't have any information to prove this claim. Kim Loos Dr. Kimberly A. Loos practices general dentistry in San Jose, California. She is also a clinical instructor at University of Pacific School of Dentistry and an editor for Dentistry On-Line. This nebulous claim could mean that the juice producer donates a percentage of sales to purchase toothbrushes for the community. Or, the label may be referring to the fluoride, calcium, or tannins found in cranberries.
Many fruit juices contain fluoride.
As you know, fluoride has been shown to prevent cavities. The fluoride concentration in cranberry juice is highly variable. Reconstituted juice may contain excessive amounts of fluoride depending on the water supply used to make the juice. Too much fluoride can cause dental fluorosis. In addition, calcium helps build strong teeth.