There Is Now an Alternative to Fluoride

For as long as I can remember, I have bought into the gospel of fluoride, believing that my teeth would surely rot out of my head without its protection. So it felt a little bit illicit, recently, when I purchased a box of German fluoride-free kids’ toothpaste for my daughter. The toothpaste came in blue, understated packaging—no cartoon characters or candy flavors—which I associated with German practicality. And instead of fluoride, it contained an anticavity ingredient called hydroxyapatite, vouched for by several dental researchers I interviewed for this story. Could it be, I wondered as I clicked “Buy,” that toothpaste doesn’t need to contain fluoride after all?

The scientific case for hydroxyapatite toothpaste is actually quite simple: Composed of calcium and phosphate, hydroxyapatite is the very mineral that primarily makes up our bones and teeth. Tooth enamel, the hard protective outer layer, is naturally about 96 percent hydroxyapatite. NASA researchers first patented an idea for repairing teeth with a hydroxyapatite precursor in the 1970s; nothing came of it then, but a Japanese company acquired the patent and eventually created a popular toothpaste called Apagard. Hydroxyapatite toothpaste has been approved for cavity prevention in Japan since 1993. It is also approved in Canada and endorsed by the Canadian Dental Association. And it’s sold in Europe, where the European Commission has deemed the ingredient safe in toothpaste.

In the United States, however, fluoride still reigns supreme. You likely won’t find toothpaste containing hydroxyapatite at your corner drugstore. A few boutique hydroxyapatite-based brands have popped up, but they cannot market themselves for cavity prevention without FDA approval, a long and expensive process that no hydroxyapatite toothpaste has yet gone through. The American Dental Association (ADA), meanwhile, gives its Seal of Acceptance only to toothpastes that contain fluoride.

Fluoride does work remarkably well: It is incorporated into the enamel structure of the tooth itself, forming a mineral crystal that is significantly more resistant to cavity-causing acid than the tooth’s natural material, according Bernhard Ganss, a scientist at the University of Toronto’s Faculty of Dentistry. “​​The dogma in dentistry has always been: Fluoride is a good thing.”

The trouble with fluoride is that, at very high levels, it becomes a bad thing. Ingesting too much can lead to a condition called fluorosis, in which teeth become mottled in mild cases or structurally weak in more serious ones. The same can happen to bones. More controversially, high levels of fluoride in drinking water—higher than the level recommended in the U.S., but lower than the current EPA limit—have been linked to lower IQ in children. Toothpaste typically contains more than 1,000 times the fluoride recommended in drinking water. We use much less toothpaste than water, of course, and it’s not meant to be swallowed, but young children do not spit out toothpaste reliably.

Hydroxyapatite is a way to sidestep the fluoride controversy. It offers the anticavity benefits of fluoride, but without the risks. Bennett Amaechi, a dentistry professor at the University of Texas Health Science Center at San Antonio, says he now recommends it to parents who have concerns about fluoride. He has collaborated with toothpaste manufacturers to study ​​hydroxyapatite, but Felicitas Bidlack told me the same thing about its utility. Bidlack is not a dentist, but she is a tooth enamel researcher, recommended to me by the American Dental Association, which one could hardly accuse of being anti-fluoride. Yet for kids under 2 still learning not to swallow toothpaste, she would likely choose hydroxyapatite. “That’s what I would do as a mother,” she told me.

Fluoride toothpaste is in a bit of catch-22, Bidlack added. Sweet candy flavors, bright colors, and glitter can make toothpaste enticing enough for kids to want to brush their teeth, but if it’s too enticing, kids might simply eat it. “If you provide fluoride with this good-tasting goo that they put in their mouths, there is definitely a risk of unintentional ingestion,” says Ganss, who has published papers on hydroxyapatite in collaboration with scientists from the Dr. Wolff Group, a German business that manufactures toothpaste. He went even further: For very young kids, “I would actually really stand up and say no fluoride, period.”

I found these conversations clarifying, as they cut through the contradictory advice I’ve been given about fluoride for my 1-year-old. Toothpaste marketed to kids under 2 in the U.S. does not in fact contain fluoride (it usually contains a sugar alcohol called xylitol), and toothpastes that do contain fluoride are labeled as unsuitable for kids younger than 2 unless instructed by a doctor. But the American Academy of Pediatrics, whose guidelines our pediatrician repeated, says to use fluoride toothpaste as soon as the first tooth appears—though only a rice-size smear, which would limit exposure to fluoride. So is fluoride good or not? Is it safe or not? Wouldn’t it be nice not to deal with fluoride at all?

Hydroxyapatite’s track record is not as long as fluoride’s, but the evidence so far looks good: In clinical trials that have followed kids or adults for six months to a year and a half—largely funded by toothpaste manufacturers—hydroxyapatite and fluoride have come out about equally protective against cavities. Hydroxyapatite is chemically not as resistant to cavity-causing acid as the mineral formed by fluoride, but Ganss says that daily brushing might replenish hydroxyapatite often enough that the real-world protection is the same. The mineral may also have some other benefits: In studies, hydroxyapatite has helped reduce tooth sensitivity and the amount of bacteria stuck to teeth. The one thing it cannot do is resolve the controversy over adding fluoride to drinking water, which is done as a public-health measure in most parts of the U.S. to prevent tooth decay. Hydroxyapatite can’t be put into drinking water, because it doesn’t dissolve at a neutral pH. “The tap water would be milky,” Ganss says. “It would probably clog all your pipes within a few days or so.”

The researchers I spoke with thought fluoride still had its uses, particularly in treatments and toothpaste for adults who know not to swallow too much. Amaechi still brushes with the Colgate he’s used all his life, as he sees no reason for him, as an adult, to change his habits. But he does recommend hydroxyapatite in specific situations—for example, patients with dry mouth, he says, may particularly benefit from this formulation.

Age 2 isn't some magic threshold at which the calculus regarding toothpaste in small children suddenly changes, of course. Canada, in fact, recommends holding off on fluoride for most kids until age 3; fluoride-free options for kids are now expanding in the U.S., even without FDA approval of hydroxyapatite. The German children’s toothpaste came only in boring white mint, but I found a number of brands in the U.S. already selling more tempting flavors, such as orange creamsicle and birthday cake.