Is Fluoride Safe? A Mom/Dentist Perspective
Hi friends, Dr. Monica here.
I talked about toothbrushing time in my last blog and briefly touched on the specific use of fluoride toothpaste before highlighting specific toothbrushing tips. So now I want to take some time to focus on fluoride itself, whether or not it’s safe, what the governing bodies show, what the studies have shown, and what I personally do for my own children (Ages 2.5 and 4 months).
Before I had my boys, I assumed the most controversial thing I'd ever discuss at a playground was how new Disney movies aren’t as good as the 90s classics. Turns out, mentioning fluoride at a mom’s group and you’d think I dropped a wine glass.
So let's talk! As a pediatric dentist and mom of 2, I'm going to tell you exactly what I do for my own boys and why.
Okay, what IS fluoride, and what does it actually do?
Fluoride is one of the most abundant naturally occurring minerals on Earth. It’s found in almost all sources of water, all over Earth. It's not a drug someone invented in a lab — it's already in the ground, in the ocean, and in fresh fruits and veggies.
Fluoride prevents cavities in three ways:
It strengthens enamel. Tooth enamel is made of a mineral called hydroxyapatite. When exposed to fluoride, this mineral is upgraded to Fluorapatite. Basically, Fluoride gets incorporated into the tooth structure to create fluorapatite, which is more resistant to acid (and therefore cavities) than the enamel your child was born with.
It remineralizes. This is the big one. When acid pulls minerals out of enamel, fluoride helps put minerals back — meaning it can heal early damage before it ever becomes a cavity. Your dentist may have even diagnosed some small cavities, or “incipient” cavities. These are cavities that are limited to the outer layer of the tooth (the enamel). These have the chance to heal, or remineralize.
It messes with the bacteria. Fluoride interferes with the metabolism of the bacteria that cause cavities, so they make less acid in the first place.
Is fluoride in the water safe?
Community water fluoridation has been called one of the ten greatest public health achievements of the twentieth century. It's been in use in the U.S. since the 1940s.
The current U.S. Public Health Service recommendation for fluoride levels in water is is 0.7 parts per million (ppm). That number was lowered in 2015; not because fluoride became unsafe, but because kids now get fluoride from lots of places (toothpaste, the dentist, vegetables, beverages), so the water level was adjusted down to keep everything balanced.
What do we get in return for fluoridated water?
About a 35% reduction in decayed, missing, and filled baby teeth
About a 26% reduction in decayed, missing, and filled permanent teeth
A Cochrane review found water fluoridation led to a 15% increase in cavity-free kids in the baby teeth and a 14% increase in the permanent teeth
Every major health organization — the American Academy of Pediatrics, the CDC, the American Dental Association, and my own American Academy of Pediatric Dentistry — supports it.
Can’t we just remove fluoride from our water? Honestly, what’s the worst that could happen?
This section of the blog I will call The Tale of Two Cities. And we’re going on a field trip to Alberta, Canada.
Calgary and Edmonton are the two biggest cities in the Alberta. Similar in size and population demographics. Edmonton has fluoridated its water since 1967. Calgary started in 1991 and then stopped in 2011.
Seven years later, researchers at the local universities in both cities went into the schools and checked the teeth of more than 5,000 second graders — kids who had been born after the fluoride stopped in Calgary. Real dental exams, done by hygienists. Parents filled out surveys about brushing, flossing, diet, and dentist visits.
Here's what they found. In Calgary (the city with no fluoride) 65% of the kids had cavities in their baby teeth. In Edmonton, it was 55%. The average Calgary seven-year-old had almost four baby teeth affected. In Edmonton, closer to two and a half.
Okay, so a…10% difference? That’s hardly significant at all, right? Honestly, yeah not huge. But here’s the detail that makes that 10% jump.
The Calgary parents were doing more, not less.
More of them brushed twice a day, more of them flossed, and more of them had taken their kid to the dentist in the past year. More of them said no to sugary junk food.
Those moms were working harder — making the appointments, buying the products, fighting the toothbrushing battle — and their kids still ended up with 10% more cavities than the kids in the city where the remineralizing fluoride was just sitting there in the tap water.
What ended up happening, is that Calgary voted to bring fluoride back. In 2021, 62% of voters said yes, and the water was fluoridated again starting in June 2025. They turned it off, saw what happened, then turned it back on.
I saw a study that said fluoride lowers IQ, though!
I’ve heard people talk about this on Instagram and Tik Tok, and the studies are real.
One widely-shared Canadian study reported a difference in IQ of children in areas of different fluoride levels, but the lower IQ levels were found in the higher fluoride area that was more rural and remote. Is there any other reason that the high fluoride/rural area had lower IQ levels than the urban/suburban low fluoride area? The study didn’t ask this. They didn’t measure anything else. Okay, so did the people in the rural area have access to healthy fruits and vegetables? Did people have access to a doctor for routine checkups or illnesses? Did they have well-funded schools? Did they have to close the schools more frequently due to floods/snow and no way to clear these country roads? Were there enough teachers out there?
None of these questions were asked or accounted for. And those are just the questions I came up with off the top of my head. Meanwhile, a study in New Zealand found no association between fluoride levels and IQ, and a study in Sweden found no relationship between fluoride in water supplies and cognitive ability.
The current evidence does not support that water fluoridated at 0.7 ppm is associated with reductions in IQ. That's not me being defensive — that's where the body of research sits right now. The same goes for cancer, endocrine disruption, and the gut microbiome. Large cohort studies and systematic reviews have looked, repeatedly, and haven't found a credible link at recommended levels. If you have found a study that showed negative effects of fluoridated water; see if the study mentions what level the fluoride is at. Most of these studies measure the effects of when there is natural fluoride in the water at way higher concentrations than what is recommended; at which case, residents of these areas should probably filter out the fluoride with expensive reverse osmosis filters.
What about fluorosis? I've heard about white spots.
This one is real, and it's the reason we're so specific about how much toothpaste to use, and how much fluoride is added to the water.
Dental fluorosis happens when a child swallows too much fluoride while the permanent teeth are still forming — roughly ages 15 to 30 months is the most susceptible window for the front permanent teeth. Very mild and mild fluorosis shows up as diffuse, lacy white spots in the enamel. It's cosmetic. It's usually not even noticeable to anyone but a dentist with a magnifying loupe, and it's actually associated with fewer cavities.
The way to avoid the not-cosmetic-anymore version is boring and simple: use the right amount of toothpaste, and supervise.
As well, if you are feeding your baby using powdered formula mixed with water, be sure and use distilled water for this. Most baby formulas have a small amount of fluoride in it already, so if you use fluoridated tap water to mix it, this can increase the risk of mild fluorosis on the permanent teeth.
Powdered baby formula = use distilled water.
How much fluoride is in my water?
This information is publicly accessible, and the government does its best to make it easy to find. It…it does its best. You can do a google search for your town and county and likely find the public records. As well, you can go to the CDC Website here. On this website, click on your state on the map, or the “State Fluoridation Reports” on the left, and start putting in your local info. It will pull the report if it can. If it can’t, contact your water company and they should be able to tell you!
So how much toothpaste again?
For the people in the back:
Kids 0–3 years old: grain-of-rice sized smear (about 0.1 mg fluoride)
Kids 3–6 years old: pea-sized amount (about 0.25 mg fluoride)
Brush 2x/day. Any brand, any flavor. Start as soon as you see a tooth.
And once your child is old enough to spit, have them spit — but don't rinse with water. Leaving that film on the teeth overnight lets the fluoride keep working, like lotion for enamel.
What about our water at home? We drink bottled/well/filtered.
Great question, and one I ask every parent at their child's visit.
Municipal water: most systems are fluoridated to 0.7 ppm. You can look up your specific water report.
Well water: could be anywhere from zero to naturally high. Get it tested — we can help you interpret the number.
Bottled water and reverse-osmosis filters: usually little to no fluoride. Standard carbon pitcher filters generally don't remove it, but RO systems do.
Formula: ready-to-feed formulas average around 0.15 ppm (milk-based) and 0.21 ppm (soy). Powdered formula reconstituted with fluoridated water is fine at today's 0.7 ppm — the risk of fluorosis from this dropped when the water standard came down. If you're worried, you can alternate with low-fluoride bottled water. But please don't stress about this one.
What about fluoride supplements?
If your child drinks water that's low in fluoride and is at higher risk for cavities, we may prescribe a supplement. This is prescription-only and dose depends on age and your water's fluoride level.
Before we prescribe anything, we add up every source: water at home, water at daycare, water at grandma's, juice, soda, prepared foods, toothpaste. More is not better here. That's the whole point. Because there’s so many other areas kids naturally get fluoride (toothpaste, veggies, tap water etc) we rarely, if ever, need to prescribe fluoride supplements anymore.
What's that sticky stuff you paint on at the visit?
That's 5% sodium fluoride varnish, and it's the single most bang-for-your-buck thing we do at a checkup.
It's the only professionally-applied topical fluoride recommended for kids under 6, because unit-dose packaging limits how much is available to swallow
Kids at risk for cavities should get it at least every 6 months — and if your child is higher risk, we may recommend every 3 months
It works on baby teeth and permanent teeth
It can even arrest early white-spot lesions before they become real cavities
Your kid will have slightly fuzzy-feeling teeth for a few hours. Skip the crunchy foods that night. That's the whole recovery plan.
And the stuff that turns cavities black?
Silver diammine fluoride (SDF). It's a liquid we paint on a cavity to stop it in its tracks — the silver kills the bacteria, the fluoride remineralizes. Clinical trials show 1-2 applications of it arrests cavities better than 4 applications of fluoride varnish alone.
The catch: the arrested cavity stains black. Permanently, until it's restored.
We use it as part of a bigger plan — for very young kids who can't tolerate treatment yet, for children with special healthcare needs, and to buy time and stop pain while we get to a definitive fix. It is not a substitute for a dental home. It's a tool in the bag.
My kid is older / has braces. Is regular toothpaste enough?
For kids 6 and older at higher risk — including teens, teens with special healthcare needs, and those in braces — we can prescribe stronger home products: 5000 ppm prescription toothpaste. These are not for the toddler crowd, because they require reliable spitting. The prescription strength means it’s 5 times the concentration of what you buy at the store. Although it’s rated for kids 6 and up, Dr. Matt and I typically will hold out on prescribing it until the patients have majority permanent teeth, age 11-13.
Should I be worried about my toddler eating toothpaste?
You should be mindful, not panicked.
A rice-sized smear is a rice-sized smear for a reason. But please:
You dispense the toothpaste for kids under 3, not them
Supervise brushing for any child who can't reliably spit
Keep the tube — and any prescription fluoride — out of reach and up high
The toxic dose of fluoride ingestion is around 5mg/kg. In the 0.85oz tubes of kids toothpaste we give out at the dentist, there’s 24-36mg of fluoride in there. Let’s call it 36. This means if your 30lb toddler swallowed the whole tube, this would be about 2.65mg/kg of ingestion. Below the “toxic” threshold, but would still cause nausea, vomiting, cramps. The lethal dose of fluoride ingestion is 15mg/kg, or three times as much.
Over 20,000 fluoride ingestion calls a year go to poison control, and over 80% of them involve kids under 6. Almost all of those are "my kid ate the sparkly bubblegum toothpaste like it was frosting" and result in, at most, an upset stomach.
When in doubt, always call Poison Control (1-800-222-1222). That's what they're there for, and they are extremely nice about it. If you are unable, report to the closest emergency room.
Dr. Monica, what do you actually do with your own kids?
For Henry, our 2.5 year old:
Fluoridated toothpaste, rice-sized, 2x/day, every since his first tooth. Floss between any teeth that touch.
No rinsing after
Tap water in his sippy cup / open cups. Whole milk during snack time and meals.
Dental checkup every 6 months with fluoride varnish
For Sam, our 5 month old:
Distilled water to mix his baby formula for Fluoride varnish at every checkup
Wipe his gums with a clean cloth after feeds, so he’s used to me “brushing”
No supplements, because our water is fluoridated and I'm not stacking sources
That's it. That's the protocol. It’s cheap, effective, natural, and kinda chic. It's the single most well-researched thing you can do to keep your kid out of dental trouble.
Ready to talk through your family's water, your child's cavity risk, or anything you read online at 2 a.m. while nursing? Give us a call at 317-900-1808 or Click here to book your visit. Bring your questions. We'd love to see you!
