Toothbrush Roundup – Part 1a, Fluoride redux

Dear Dr Dad,

I read your part 1 about fluoride, but the pediatrician said not to use fluoride toothpaste if there was fluoride in our water, and the dentist said not to use fluoride toothpaste because my toddler might swallow it, but that I should give him a fluoride supplement. None of that makes sense. What gives? Why can’t anyone agree?

Confused in Canineland


Dear Confused,

There is a lot of confusion out there! But there’s not really a lot of ambiguity, if that makes sense. I think mostly people haven’t kept up with the recommendations of their professional societies.

There are two major organizations making recommendations around oral health for children: the American Academy of Pediatric Dentistry (AAPD), and the American Academy of Pediatrics (AAP).

Both of these organizations agree that all children should use a smear of fluoride toothpaste from emergence of first tooth, regardless of risk status, and regardless of fluoridation status of the water.

The American Dental Association (which is a dental specialty organization, though not specifically for children) also makes the same recommendation. And the American Academy of Family Physicians, as part of the Choosing Wisely campaign (a campaign to promote evidence-based medicine), also makes the same recommendation.

  • smear of toothpaste vs pea sized amountAAP: “Fluoridated toothpaste is recommended for all children starting at tooth eruption, regardless of caries risk.” (emphasis mine) (2014, AAP Recommends Fluoride to Prevent Dental Caries)
  • AAPD: The AAPD “encourages the brushing of teeth with appropriate amounts of fluoride toothpaste (e.g., no more than a smear or rice-sized amount for children less than three years of age; no more than a pea-sized amount for children aged three to six) twice daily for all children.” (2014, Guideline on Fluoride Therapy)
  • ADA: “For children younger than 3 years, caregivers should begin brushing children’s teeth as soon as they begin to come into the mouth by using fluoride toothpaste in an amount no more than a smear or the size of a grain of rice (Figure). Brush teeth thoroughly twice per day (morning and night) or as directed by a dentist or physician. Supervise children’s brushing to ensure that they use the appropriate amount of toothpaste” (2014, Fluoride toothpaste use for young children)
  • AAFP: “The benefit of fluoride-containing toothpaste arises from its topical effect on dental enamel by interrupting enamel demineralization caused by bacterial acids and enhancing remineralization of the enamel surface. Anti-caries (anti-cavities) benefit begins with eruption of the first primary tooth. Brushing with nonfluoridated toothpaste provides no anti-caries benefit. Use of recommended amounts of fluoride toothpaste minimizes risks of fluorosis, a whitish discoloration of enamel.” (Choosing Wisely, Don’t recommend nonfluoride toothpaste for infants and children.)

Why was there ever a recommendation to the contrary? What’s the confusion about?

The concern was that babies might swallow the fluoride toothpaste (obviously) and end up with too much fluoride and end up with fluorosis, which are white patches on the teeth. But you can see from the recommendations above that the amounts of fluoride recommended are tiny, and the benefit in preventing cavities is thought to be worth the very small risk of fluorosis.

What is risk-dependent is whether or not a child is prescribed a fluoride supplement, whether or not they’re recommended an over-the-counter fluoride mouth rinse, how often they go to the dentist, etc. This is a risk assessment table from one caries risk assessment tool from the AAP:

Fluoride supplement prescription is specifically tied to the fluoride content of the drinking water:


What about fluoride toxicity?

The toxic dose of fluoride is 5-10 mg/kg of body weight. Lethal doses have been calculated to be between 8-16 mg/kg. If your child is prescribed a fluoride supplement, keep it out of reach. In terms of toothpaste, for example, Tom’s of Maine Silly Strawberry anti cavity (fluoride containing) toothpaste for kids has 0.13% weight for volume of fluoride ion (less than the typical adult formulation of 0.15% w/v). A tube of that toothpaste specifically is 119 g. 0.13% of 119 g is 0.1547 g of fluoride, or 154.7 mg. Your 20-pound toddler converts to roughly 9 kg, so a toxic dose would be 45 mg. This is achievable with a dedication to eating toothpaste, so treat your fluoride toothpaste like medication/supplements and keep it out of reach.


What about xylitol toothpaste?

It’s actually not clear to what extent xylitol toothpaste helps prevent cavities. It’s also not clear to what extent xylitol gum or mints helps either. The doses of xylitol that have been studied are pretty high – high enough to cause diarrhea. It’s a non-cavity promoting sweetener, so it’s helpful in that regard (but again, careful with the dose), but it’s not a substitute for fluoride in the cavity-prevention world. (AAPD: Policy on the Use of Xylitol)


Hopefully that clarifies things!


%d bloggers like this: