If there is one downside to red wine, it's stained teeth -- that purple-grey coating that is a dead giveaway you've had one too many. Other dark beverages, like coffee and grape juice can stain teeth too, but none do it quite as dramatically as wine.
So what gives?
"There are three things that influence the staining of teeth," says Dr. Mark Wolff, a professor at NYU's College of Dentistry. "The first is the intensity of color, or chromogen. In red wine, that red is very intense."
But that's just the start of it.
Dr. Thomas Connelly, a HuffPost contributor and cosmetic dentist, explains that because wine is acidic, it actually dissolves -- or etches -- teeth at the microscopic level. This etching process makes the tooth's surface, which is normally smooth, more likely to accept pigment.
Which is why it's actually possible for white wine to stain teeth, too. Teeth don't necessarily soak up any color from the beverage itself, but because they're "etched," they are more likely to pick up the color of whatever you're eating or drinking at the same time.
The third and final part of the equation are the tannins in wine.
"A tannin is an astringent. It's a molecule that has a high binding capacity and wants to bind to the tooth structure," Dr. Wolff says. "Also, it tends to hold the chromogens, so that compounds the issue [of staining]."
So is there anything you can do to actually prevent wine-stained teeth?
Connelly suggests that eating a protein like cheese while you're enjoying your wine, which he says can create a kind of barrier. He also says that popping a piece of gum once you've finished works, too. The chewing stimulates saliva production, which "instantly" neutralizes the pH. Otherwise, both dentists suggest brushing your teeth soon after enjoying your wine. As long as you do, they add, your teeth should be fine.
Nancy Light, director of communications at the Wine Institute in California, seconds that red wine stains are temporary and really, are a non-issue for most of us.
"Winemakers and wine judges who tastes dozens of wines at a sitting probably need to take greater care," she says. "But I haven't noticed a lot of them walking around with stained or ruined teeth."
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