THE FUSS ABOUT FLUORIDE

Toothpaste's star ingredient has recently come under fire. Here's what you need to know.

- MERYL DAVIDS LANDAU

Who hasn't dashed into the drugstore and been stymied by the overwhelming number of toothpaste options: mint, fruity, gel, whitening, sensitive-and, increasingly, fluoride-free? Even major companies like Colgate have followed the trend, joining no-fluoride mainstays like Dr. Bronner's and Tom's of Maine. No wonder global sales of toothpaste sans fluoride-a mineral that appears naturally in rocks, soil, and water-are over $6 billion and projected to soar above $10 billion within a decade.

Fluoride was added to toothpaste, as well as many community water systems, in the 1950s after scientists realized that people whose drinking water was naturally higher in fluoride had much less tooth decay. But lately there has been growing criticism of fluoride, with some communities passing or debating legislation to remove the mineral from their water. And now the debate has reached the toothpaste aisle.

But is there a good reason to opt for a toothpaste without this long-used ingredient? Prevention bit into years of research to find out.

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To some extent, say many dentists, fluoride is a victim of its own success-it's a key reason so many of us sport healthy smiles. We're so unused to major tooth decay that we've forgotten how we got here.

As Americans decades ago were all too aware, cavities are destructive holes in teeth that form when the bacteria that consume sugars in our mouths (from sweets and other carbs) produce acids. These acids can dissolve the protective enamel on a tooth's surface, forming a cavity. Fluoride strengthens resistance to acid and can replenish some of the enamel the bacteria destroy, says Mark Wolff, D.D.S., Ph.D., dean of the School of Dental Medicine at the University of Pennsylvania. In children, fluoridated water strengthens permanent teeth as they start to come in.