The Weird Way Red Wine Fights Cavities - (Excerpts) Prevention News by Linda Melone
"This study is about applying something to the teeth that decreases bacteria. The effectiveness of this type of product (red wine) depends on how long it stays on the tooth, known as its 'substantivity,' " says Gary L. Glasband, DDS, a dentist in private practice in Long Beach, California, who was not involved in this study. "Wine has a high substantivity, which you can see as it stains the teeth when you drink it."
This, combined with the antioxidants present in grape seeds, makes red wine effective at killing bacteria on the teeth.
While the antioxidant effect of red wine or grape seed extract likely works to reduce cavities, it's a trade-off between the pros and the cons: a reduced risk of cavities vs. stained teeth and excess calories from the alcohol, says Glasband. Just as caffeine and dark chocolate offer health benefits when consumed in moderation, you should enjoy red wine the same way, he suggests. But gargling with red wine to prevent cavities, on the other hand, isn't going to get the job done.