Chapter 27: The Fluoride Question

No topic in oral health generates more controversy than fluoride. I've watched the debates rage since Frederick McKay first noticed that children in Colorado Springs had strangely mottled—but remarkably cavity-free—teeth in the early 20^th century.¹ That observation led to the discovery of fluoride's effects, and eventually to one of the most successful public health interventions in human history.

And yet, here we are, with substantial segments of the population convinced that fluoride is a poison, a mind-control agent, or at minimum an unnecessary intervention. Let me cut through the noise and explain what fluoride actually does, what the evidence actually shows, and where legitimate concerns exist versus manufactured controversy.

The Mechanism: How Fluoride Actually Works

Understanding fluoride requires returning to the chemistry of enamel we discussed in Part I. Remember that hydroxyapatite exists in equilibrium with the surrounding oral fluid:

\[\text{Ca}_{10}(\text{PO}_4)_6(\text{OH})_2 \rightleftharpoons 10\text{Ca}^{2+} + 6\text{PO}_4^{3-} + 2\text{OH}^-\]

When fluoride ions are present during remineralization, something interesting happens: they substitute for hydroxide ions in the crystal lattice, creating fluorapatite or fluorhydroxyapatite:

\[\text{Ca}_{10}(\text{PO}_4)_6\text{F}_2 \text{ (fluorapatite)}\]

\[\text{Ca}_{10}(\text{PO}_4)_6(\text{OH})\text{F} \text{ (fluorhydroxyapatite)}\]

This substitution has profound consequences:

Lower Solubility

Fluorapatite has a significantly lower solubility product constant (Ksp) than hydroxyapatite. In practical terms, this means:

Mineral Phase	Critical pH
Hydroxyapatite	~5.5
Fluorapatite	~4.5

The enamel surface can withstand a full pH unit more acid exposure before demineralization begins. That's enormous—it's the difference between losing mineral during a normal meal and retaining it.

Enhanced Remineralization

When fluoride is present in the oral environment (from toothpaste, rinse, or saliva), it accelerates the remineralization process. It does this by:

1. Adsorbing to partially demineralized enamel surfaces
2. Attracting calcium ions to the site
3. Acting as a template for new crystal growth
4. Creating a fluoride-enriched surface layer more resistant to future attack

This is why topical fluoride (direct contact with teeth) is more important than systemic fluoride (swallowed, incorporated during tooth development) for preventing decay in erupted teeth.

Antimicrobial Effects

At higher concentrations, fluoride also interferes with bacterial metabolism:

• Inhibits enolase, a key enzyme in bacterial glycolysis
• Interferes with proton-translocating ATPases
• Reduces acid production by S. mutans

These effects are secondary to the mineral chemistry effects but contribute to overall caries reduction.

The Evidence: What Do We Actually Know?

The evidence base for fluoride is vast—thousands of studies over 80+ years. Here's a summary of what's well-established:

Water Fluoridation

Community water fluoridation at 0.7 ppm (the current US recommendation) reduces caries — though the magnitude of benefit has shrunk considerably over the decades. The 2000 York systematic review found a median reduction of 2.25 decayed teeth per child in fluoridated areas.² The most comprehensive Cochrane review to date (Iheozor-Ejiofor et al., 2024, analyzing 157 studies) tells a more nuanced story:⁶

• Pre-1975 studies: roughly 2.1 fewer decayed baby teeth per child in fluoridated areas
• Contemporary studies (post-1975): only 0.24 fewer decayed baby teeth per child

The likely reason? Fluoride toothpaste became widespread. When everyone's teeth already get topical fluoride twice a day, water fluoridation adds a smaller incremental benefit. The Cochrane review also found no evidence that water fluoridation reduces oral health inequalities — a common justification for the policy.

Water fluoridation still works. But the dramatic caries reductions cited for decades were measured before fluoride toothpaste was universal. In practice, topical fluoride from toothpaste is where most of the action is — which makes the "spit, don't rinse" technique even more important.

Fluoride Toothpaste

Toothpastes containing 1000-1500 ppm fluoride reduce caries by approximately:

• 24% compared to non-fluoride toothpaste (Cochrane review of 74 trials, 42,300 children)³
• Effects are dose-dependent: higher concentrations (within recommended limits) provide more protection
• Effects are enhanced by not rinsing with water after brushing

Fluoride Rinses

Over-the-counter fluoride rinses (typically 0.05% NaF = 225 ppm F⁻) provide:

• Approximately 26% reduction in caries compared to no rinse (Cochrane review)⁷ — though the incremental benefit for those already using fluoride toothpaste is more modest
• Particularly beneficial for high-risk individuals
• Most effective when used before bed

Professional Fluoride Applications

In-office fluoride varnish or gel provides:

• Additional protection for high-risk individuals
• Particularly valuable after orthodontic treatment, for patients with dry mouth, or those with rampant caries

Legitimate Concerns

Not all fluoride concerns are conspiracy theories. There are genuine issues worth understanding:

Dental Fluorosis

Excessive fluoride ingestion during tooth development (roughly ages 0-8 for permanent teeth) can cause fluorosis—a disruption of enamel formation resulting in white spots, mottling, or in severe cases, brown staining and pitting.

The dose-response is well-characterized:

Fluoride Intake	Fluorosis Risk
< 0.05 mg/kg/day	Minimal
0.05-0.07 mg/kg/day	Optimal (caries protection, minimal fluorosis)
0.07-0.1 mg/kg/day	Mild fluorosis risk
> 0.1 mg/kg/day	Moderate-severe fluorosis risk

This is why:

• Children's toothpaste often has lower fluoride concentrations
• Parents are advised to supervise brushing and use only a pea-sized amount
• Water fluoridation is calibrated to provide benefit without excessive intake

My position: Dental fluorosis is a real phenomenon, but mild fluorosis (white spots) is cosmetic and the teeth are actually more resistant to decay. The threshold for concerning fluorosis is well above typical exposure levels from fluoridated water and appropriate toothpaste use.

Skeletal Fluorosis

At very high chronic intake levels (8+ ppm in water for years), fluoride can accumulate in bones and cause skeletal fluorosis—joint stiffness, bone pain, and in extreme cases, crippling deformity. This is a genuine public health problem in some regions with naturally high fluoride in groundwater (parts of India, China, East Africa).

At 0.7 ppm (US water fluoridation level), skeletal fluorosis does not occur. The safety margin is substantial.

Neurodevelopmental Concerns

In August 2024, the National Toxicology Program released its final monograph — the most comprehensive governmental review to date — concluding with "moderate confidence" that fluoride exposure above 1.5 mg/L is associated with lower IQ in children, based on 72 epidemiological studies (19 rated high quality).⁴

That's a real finding, and I won't pretend otherwise. But the nuance matters enormously:

• The NTP monograph explicitly states it does not address whether fluoride at 0.7 mg/L (the US/Canadian water fluoridation level) has measurable cognitive effects — there simply isn't enough data at that concentration
• 1.5 mg/L is more than double the US fluoridation level
• Animal and mechanistic evidence was deemed insufficient to support the epidemiological findings
• Confounding factors (arsenic co-exposure, iodine deficiency, socioeconomic conditions) remain difficult to fully control in the studies reviewed

My position: The NTP finding at >1.5 mg/L is concerning and deserves continued research. But it does not indict fluoride at recommended water fluoridation levels. The proven benefit of caries reduction at 0.7 ppm is weighed against an association seen only at concentrations more than double that level — in the context of a monograph that explicitly declines to draw conclusions about the lower dose.

What happened next (2025–2026)

A great deal, and it did not all point the same way. I'm going to walk you through it in order, because this is the part of the book where you are most likely to be handed a headline by someone with an agenda, and I would rather you had the actual shape of the evidence.

January 2025 — the meta-analysis. Researchers at the National Institute of Environmental Health Sciences published a meta-analysis of 74 studies in JAMA Pediatrics, reporting that children's IQ fell by about 1.63 points for every 1 mg/L of fluoride in their urine.⁸ This is the study you have heard about.

Now the parts you probably haven't. None of the 74 studies were conducted in the United States — the authors say so plainly. Forty-five were from China, twelve from India. Fifty-two of the 74 were rated high risk of bias. And the dose-response table, which is where this question actually lives, reads like this:

Water fluoride	All studies	Low risk-of-bias studies only
Below 4 mg/L	significant	—
Below 2 mg/L	not significant (p=0.10)	significant
Below 1.5 mg/L	null — the sign flips positive (p=0.82)	not significant (p=0.28)

There is no analysis at 0.7 mg/L anywhere in that paper. The lowest cut-point is 1.5. Anyone telling you this study found harm at American water fluoridation levels is extrapolating past the bottom of the table.

The fight over it. JAMA Pediatrics published two opposing commentaries the same day, which tells you how split the field is.⁹ A subsequent letter charged that seven of the thirteen urinary regression coefficients could not be located in the original papers.¹⁰ An independent preprint found that 21 of the 74 included publications came from a journal called Fluoride, which is not MEDLINE-indexed and has anti-fluoridation editorship — and that the negative effect depended on whether a study came from that journal.¹¹ It also identified studies with statistically impossible numbers. The NIEHS authors answered all of this in a point-by-point rebuttal at the end of 2025.¹² No correction has been issued to the original paper.

Then the cohorts arrived, and they were null. An Australian cohort following children into adulthood found no IQ deficit — if anything a slight positive.¹³ A nationally representative American study of 26,820 people found fluoridation associated with modestly better adolescent cognition.¹⁴ A Wisconsin cohort of 10,317 people, tracked from adolescence into their eighties, found nothing.¹⁵ Notably, the research group that raised the original alarm published a null result of their own on autistic behaviors.¹⁶

And then, in August 2026, a signal. The ECHO consortium studied 2,514 American children with individually estimated prenatal water fluoride exposure and found a breakpoint at 675 µg/L, above which fluid cognition fell by about 0.67 points per additional 100 µg/L.¹⁷ That breakpoint sits just below 0.7 mg/L — which is to say, just below where America sets its taps.

I am not going to pretend that isn't unsettling. I am also not going to let you mistake it for a conclusion. It is one cohort, the breakpoint was found in the data rather than predicted in advance, it has not been replicated, it contradicts three larger studies published in the preceding fifteen months, and the same consortium's larger analysis of children's behavior found nothing.¹⁸ The researchers themselves note they never measured fluoride from toothpaste, tea, or food.

Where this actually stands

• Above 1.5 mg/L: an association with lower IQ, at moderate confidence. This is the NTP finding and it has held.
• At 0.7 mg/L: genuinely unsettled. Three large cohorts found nothing. One 2026 American cohort found a small effect starting just below that level. Nobody has replicated it yet.
• What would settle it: replication of the ECHO breakpoint in an independent cohort. Watch for that, and be suspicious of anyone — on either side — who tells you it's already settled.

I have changed my position on this question exactly as far as the evidence has moved, which is: from "this is about faraway places with much higher fluoride" to "this is now a live question at American levels, and I don't know how it resolves."

Thyroid Effects

Fluoride can compete with iodine in the thyroid gland, and some studies have suggested associations with hypothyroidism. However:

• Effects are primarily seen at much higher exposures than water fluoridation
• Iodine-sufficient populations show minimal effects
• Systematic reviews have not confirmed a clear causal relationship

What Actually Happened to Fluoride Policy

While the science argued with itself, the policy moved — and the two are only loosely related, which is its own lesson about how public health works.

Two states have banned community water fluoridation. Utah went first: HB 81, signed 27 March 2025, effective 7 May 2025, removing fluoridated water from roughly 43% of Utahns. Florida followed, in an agriculture omnibus bill signed 15 May 2025 and effective 1 July 2025. In June 2026, Louisiana repealed its fluoridation mandate — not a ban, but an end to the requirement for larger systems, with a local opt-out by petition and election. Other states have tried and stalled.

Nobody knows the outcome yet, and anyone who tells you otherwise is guessing. Caries takes years to show up in the data; the dentists quoted in Utah say five to seven. What we do have is evidence from places that stopped earlier. Juneau, Alaska saw caries-related procedures and inflation-adjusted treatment costs rise substantially in the years after cessation.¹⁹ Calgary's children had measurably more decay than Edmonton's, and Calgary spent $28 million putting fluoride back in 2025. An Israeli analysis published in 2026 found decay rising after cessation, concentrated in low-income children — which is the finding that recurs everywhere this is studied.²⁰ One American microsimulation projected 25.4 million additional decayed teeth and $9.8 billion in costs over five years if fluoride were removed nationally.²¹

Hold that next to the Cochrane finding I gave you earlier — that contemporary fluoridation prevents only about a quarter of a decayed baby tooth per child, and shows no evidence of reducing inequality. Both things are true. The average benefit now is small; the burden of removing it lands unevenly, on the children with the least access to a dentist. A policy can be simultaneously less impressive than its defenders claim and worse to remove than its opponents assume. I find most arguments about fluoride would improve enormously if people could hold those two thoughts at once.

Three things you will be told that are not true

"A federal court ruled fluoride is dangerous." A federal judge did rule in September 2024 that fluoridation posed an unreasonable risk under the Toxic Substances Control Act, ordering the EPA to respond. That ruling was vacated on appeal in May 2026.²² The appeals court held the judge had overstepped procedurally and sent it back to be decided again on the original trial record — which excludes the NTP monograph. It is not operative law. Anyone citing it, in either direction, is citing a decision that no longer exists.

"The federal government withdrew its fluoridation recommendation." It did not. A cabinet secretary announced an intention to in April 2025, and a Congressional Research Service report contradicted itself about it — the body text of that report states plainly that no official agency action had been released. The CDC's guidance page still recommends community water fluoridation at 0.7 mg/L.

What did happen is quieter and, I think, more consequential: the CDC's Division of Oral Health — around forty people — was eliminated in the March 2025 restructuring. The national fluoridation statistics stop at 2022. Some pages now return errors. The recommendation still stands; the staff who maintained it do not. That is not a policy reversal. It is a slower kind of disappearance, and it is harder to see.

Meanwhile the EPA has been running an accelerated review of the drinking water standard, with a protocol published in August 2026 examining two endpoints: neurodevelopmental effects including IQ, and dental fluorosis. No conclusion, no deadline, and the maximum contaminant level remains where it was set in 1986.

"Fluoride supplements are simply available by prescription." That changed on 31 October 2025, and the section below has been rewritten accordingly.

An entirely unglamorous postscript

In 2026, American water systems started running short of fluorosilicic acid — the compound most of them actually add — because Israel is a major exporter and Middle East shipping disruptions throttled the supply. Baltimore cut its dose. A Maine city stopped for the first time in fifty years. Utility managers called it unprecedented.

I include this because it is a useful corrective to the way this debate is usually conducted. Both camps talk as though fluoridation is a grand ideological choice being made in a legislature. Sometimes it's a shipping lane.

The "Spit, Don't Rinse" Revolution

Here's a practical application of fluoride science that's poorly understood by the public:

After brushing with fluoride toothpaste, do not rinse with water.

The traditional sequence—brush, spit, rinse, done—actually washes away the fluoride before it can fully benefit your teeth. The fluoride needs contact time with enamel to incorporate into the mineral phase.

The updated recommendation from many dental organizations (including the UK's National Health Service):⁵

1. Brush with fluoride toothpaste for 2 minutes
2. Spit out excess toothpaste
3. Don't rinse with water
4. Don't eat or drink for at least 30 minutes

This keeps a thin film of fluoride on your teeth, extending the contact time and maximizing remineralization benefit. It feels strange at first (you're used to the "clean rinse" feeling), but the chemistry is sound.

The Filtered Water Consideration

Many health-conscious people filter their drinking water—and honestly, I understand why. The state of municipal water quality varies widely, and concerns about chlorine byproducts, heavy metals, microplastics, and pharmaceutical residues are not unfounded. It's somewhat tragic that filtering your own water has become a reasonable precaution, but here we are.

Reverse osmosis (RO) systems, in particular, are remarkably effective at removing contaminants. They're also remarkably effective at removing fluoride.

RO removes fluoride. The fluoride ion is small but charged, and RO membranes typically remove 85-95% of fluoride from water. If your municipal water is fluoridated at 0.7 ppm, RO-filtered water probably contains less than 0.1 ppm fluoride—essentially non-fluoridated.

This creates a consideration worth thinking through:

For adults: This is probably fine. Topical fluoride from toothpaste is more important for erupted teeth than systemic fluoride from drinking water. If you're using fluoride toothpaste twice daily with the "spit, don't rinse" technique, you're getting adequate fluoride exposure to your teeth.

For children: More thought is warranted. Developing teeth benefit from systemic fluoride exposure for optimal enamel formation. If your household uses RO filtration, options to consider include:

• Ensuring adequate fluoride toothpaste use (with supervision to minimize swallowing)
• Having children drink some non-filtered water
• Discussing the situation with a pediatric dentist — including whether supplements apply, which is no longer the simple question it was

Fluoride supplements: read this before you ask for a prescription

On 31 October 2025 the FDA acted against ingestible fluoride drops and tablets for children. It did not ban them — these products were never FDA-approved in the first place, a quirk of their pre-1938 legal status — but it sent enforcement notices to manufacturers and a letter to clinicians, narrowing appropriate use to children aged 3 and older at high risk of decay.²³

This leaves a genuine conflict that nobody has resolved for you: the American Dental Association's schedule still runs from 6 months to 16 years for high-risk children, and the US Preventive Services Task Force still recommends supplementation from 6 months in fluoride-deficient areas. The ADA's response was that clinical judgment, not a warning label, should guide the decision.

Two things worth knowing as you weigh it. The FDA's letter cites a Cochrane review as concluding fluoride "did not reduce dental caries in developing teeth" — that review found the effect on baby teeth unclear, but a 24% reduction in permanent teeth.²⁴ Half a finding, reported as a whole one. And Utah, having banned fluoridated water, made fluoride pharmacist-prescribable as the substitute — five months before the FDA restricted the substitute.

The topical products are untouched by all of this. Toothpaste, mouth rinse, and in-office varnish were explicitly excluded, and that is where the evidence was strongest anyway.

The irony isn't lost on me: people filter their water to be healthier, then need to think carefully about one mineral they may have filtered out. But this is the kind of nuanced thinking that leads to genuinely good outcomes—not blindly accepting everything in tap water, but not blindly rejecting everything either.

My Overall Assessment

I've watched the fluoride controversy play out for decades, and here's my honest perspective:

Fluoride works. The evidence is overwhelming. The mechanism is well-understood. The population-level benefits are clearly documented. It's one of the few preventive interventions that has genuinely reduced disease burden at scale.

Fluoride is not without nuance. Dosing matters. Age matters. Excessive exposure has consequences. The goal is optimal exposure, not maximum exposure.

Much of the controversy is manufactured — but not all of it, and the honest part has grown. The mind-control and industrial-waste material remains what it always was. But the neurodevelopmental question at American water levels is now a real scientific disagreement between serious people, and I would be doing you a disservice to file it under conspiracy. My read is that the benefit-to-risk balance at 0.7 ppm still favors fluoridation. I hold that more loosely than I did two years ago, and I'll tell you plainly if the ECHO finding replicates.

Alternatives exist but aren't equivalent. Nano-hydroxyapatite shows promise (next chapter), but doesn't have the depth of evidence fluoride has. Rejecting fluoride entirely, without a well-considered alternative, increases caries risk.

If you're using fluoride toothpaste twice daily, not rinsing, and maintaining the other practices we've discussed, you're getting fluoride's benefits optimally — and note that this is the topical route, which is where the evidence has always been strongest and where none of 2026's arguments land. If you're on RO water and have children, talk to a dentist, with the supplement situation above in hand.

I've seen too many teeth lost to preventable decay. Fluoride has prevented millions of those losses. That's not marketing—that's observation across decades.

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1. McClure, F. J. (1970). Water Fluoridation: The Search and the Victory. National Institute of Dental Research. The definitive account of Frederick McKay's observations in Colorado Springs beginning in 1901 and the subsequent discovery of fluoride's role in caries prevention. ↩

2. McDonagh, M. S., et al. (2000). Systematic review of water fluoridation. BMJ, 321(7265), 855-859. ↩

3. Marinho, V. C., et al. (2003). Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews, (1). CD002278. For the current review of fluoride concentration specifically, see Walsh, T., et al. (2019). CD007868.pub3. ↩

4. National Toxicology Program. (2024). NTP Monograph on the Systematic Review of Fluoride Exposure and Neurodevelopmental and Cognitive Health Effects. NTP Monograph 08. U.S. Department of Health and Human Services. The final monograph, released August 2024, supersedes the 2020 draft. Available at: https://ntp.niehs.nih.gov/sites/default/files/2024-08/fluoride_final_508.pdf ↩

5. Office for Health Improvement and Disparities. (2021). Delivering better oral health: an evidence-based toolkit for prevention. 4^th edition. Recommends "spit, don't rinse" after brushing. ↩

6. Iheozor-Ejiofor, Z., et al. (2024). Water fluoridation for the prevention of dental caries. Cochrane Database of Systematic Reviews. Analysis of 157 studies; contemporary studies (post-1975) show substantially smaller caries reductions than earlier studies, likely due to widespread fluoride toothpaste availability. ↩

7. Marinho, V. C., et al. (2016). Fluoride mouthrinses for preventing dental caries in children and adolescents. Cochrane Database of Systematic Reviews, (7). CD002284. The 26% prevented fraction is compared to no rinse/placebo; the incremental benefit when already using fluoride toothpaste is smaller. ↩

8. Taylor, K. W., Eftim, S. E., Sibrizzi, C. A., et al. (2025). Fluoride exposure and children's IQ scores: a systematic review and meta-analysis. JAMA Pediatrics, 179(3), 282-292. DOI: 10.1001/jamapediatrics.2024.5542. Seventy-four publications, 64 of them cross-sectional, none conducted in the United States; 52 rated high risk of bias. The urinary-fluoride estimate is −1.63 IQ points per 1 mg/L (95% CI −2.33 to −0.93), falling to −0.78 after adjustment for publication bias. The authors state explicitly that the analysis "was not designed to address the broader public health implications of water fluoridation in the United States." Note the gap between the abstract, which says the association "remained inverse" below 1.5 mg/L, and Table 2, where that association is not statistically significant — the abstract describes a direction, not a finding. ↩

9. Published the same day: Levy, S. M. Caution needed in interpreting the evidence base on fluoride and IQ. DOI: 10.1001/jamapediatrics.2024.5539; and Lanphear, B. P., Den Besten, P., & Till, C. Time to reassess systemic fluoride exposure, again. DOI: 10.1001/jamapediatrics.2024.5549. Same journal, same issue, opposite conclusions. ↩

10. Antoon, J. W., & Kumar, J. V. (2025). Letter. JAMA Pediatrics. DOI: 10.1001/jamapediatrics.2025.0932, with the authors' reply at DOI: 10.1001/jamapediatrics.2025.0935. ↩

11. Jané, M. B., Heathers, J., & Grimes, D. R. (2025). Major flaws in Taylor et al.'s (2025) meta-analysis. OSF preprint. DOI: 10.31219/osf.io/zhm54. Not peer-reviewed — but the arithmetic in it is checkable, which is why I'm citing it. Its central findings: 21 of the 74 included publications came from the journal Fluoride, and the pooled negative effect depended on whether a study appeared there; several included studies report statistically impossible values, such as an IQ standard deviation of 0.92 against a population norm of 15. ↩

12. Taylor, K. W., et al. (2025). Addressing critiques of the evidence linking fluoride and children's IQ. Annals of Global Health, 91(1), 83. DOI: 10.5334/aogh.4853. A systematic answer to twelve critiques, published December 2025. Read it alongside the critiques rather than instead of them — and note that it, too, describes associations below 1.5 mg/L as "observable," which overstates what their own dose-response table shows for drinking water. ↩

13. Do, L. G., et al. (2025). Journal of Dental Research, 104(3), 243-250. DOI: 10.1177/00220345241299352. Australian national cohort, 357 participants, IQ measured at ages 16-26. Estimate for 100% versus 0% fluoridated water exposure in the first five years of life: +1.07 IQ points (95% CI −2.86 to +5.01). ↩

14. Warren, J. R., et al. (2025). Science Advances, 11(47), eadz0757. DOI: 10.1126/sciadv.adz0757. Nationally representative US sample, 26,820 participants, exposure from conception through adolescence at policy-relevant concentrations. Found modestly better adolescent cognition, an advantage that disappeared by around age 60. ↩

15. Warren, J. R., et al. (2026). PNAS, 123(16), e2536005123. DOI: 10.1073/pnas.2536005123. Wisconsin Longitudinal Study, 10,317 participants, IQ in adolescence plus cognition at ages 53, 64, 72 and 80. Roughly two of 45 coefficients reached significance — about what chance predicts. ↩

16. Carty, A., et al. (2025). Environmental Health, 24, 87. DOI: 10.1186/s12940-025-01237-9. Canadian MIREC cohort, autistic behaviors at ages 3-4, three exposure metrics, no association found. Worth noting that this comes from the research group whose earlier work raised the fluoride-neurodevelopment question in North America. Publishing your own null result is a mark of good faith. ↩

17. Simon, K. R., Bloomquist, T., Rajeev, T., et al. (2026). Prenatal exposure to fluoride in public water and child cognition in the US ECHO cohort, 2006-2019. American Journal of Epidemiology. DOI: 10.1093/aje/kwag186. Published online 14 August 2026. 2,514 children across 17 sites in 23 states; mean prenatal exposure 396.9 µg/L. A data-derived change point at 675 µg/L, above which fluid cognition fell 0.67 points per additional 100 µg/L (95% CI −0.92 to −0.42). Unreplicated as of this writing. The consortium's own statement notes it did not measure total fluoride intake from toothpaste, tea, or food, and "does not evaluate the overall benefits and risks of community water fluoridation." ↩

18. Hernandez, A., Nigra, A. E., Simon, K. R., et al. (2026). JAMA Network Open, 9(9), e2629389. DOI: 10.1001/jamanetworkopen.2026.29389. The same consortium, 5,520 children, child behavior checklist outcomes: null in both directions. ↩

19. Meyer, J., et al. (2018). BMC Oral Health, 18, 215. DOI: 10.1186/s12903-018-0684-2. Juneau, Alaska Medicaid claims, comparing 2003 with 2012 — five years after cessation. Caries-related procedures rose in children, and inflation-adjusted treatment costs rose between 28% and 111% depending on age group. See also McLaren, L., et al. (2022). Community Dentistry and Oral Epidemiology. DOI: 10.1111/cdoe.12685, comparing Calgary with Edmonton. ↩

20. Effect of community water fluoridation cessation on dental caries in 12-year-old Israeli children: a retrospective analysis of socioeconomic disparities, 2014-2022 (2026). Israel Journal of Health Policy Research. DOI: 10.1186/s13584-026-00782-z. Decay rose after cessation, concentrated among low-socioeconomic-status children. ↩

21. Choi, S. E., & Simon, L. (2025). Projected outcomes of removing fluoride from US public water systems. JAMA Health Forum, 6(5), e251166. DOI: 10.1001/jamahealthforum.2025.1166. A microsimulation built on NHANES data, so it inherits the uncertainty of its inputs: over five years, 25.4 million additional decayed teeth and $9.8 billion in costs, falling disproportionately on publicly insured and uninsured children. A correction was issued to this paper covering mis-cited references and a cost interval printed with the wrong sign; make sure you are reading the corrected version. ↩

22. Food & Water Watch v. EPA, 9^th Cir. No. 25-384, decided 21 May 2026 (unpublished memorandum), vacating and remanding D.C. No. 3:17-cv-02162-EMC (N.D. Cal.). The panel held the district court had overstepped procedurally and must rule again on the first trial record alone — a record that predates the NTP monograph. The appeals court did not decide whether fluoride at 0.7 mg/L poses an unreasonable risk. As of this writing there is no ruling on remand. ↩

23. US Food and Drug Administration (31 October 2025). Ingestible fluoride drug products: what health care professionals should know, and the accompanying announcement, FDA acts to protect children from unapproved fluoride drug products. Enforcement notices to four companies; use narrowed to children aged 3 and older at high caries risk. Topical products — toothpaste, rinses, in-office varnish — are explicitly excluded. Compare the ADA's evidence-based supplement schedule (Rozier, R. G., et al., JADA, 2010), which runs from 6 months to 16 years for high-risk children, and the USPSTF's 2021 recommendation of supplementation from 6 months in fluoride-deficient areas. That conflict is unresolved. ↩

24. Tubert-Jeannin, S., et al. (2011). Fluoride supplements for preventing dental caries in children. Cochrane Database of Systematic Reviews, CD007592.pub2. Eleven studies, 7,196 children. The effect on primary teeth was unclear; permanent teeth showed a 24% reduction in decayed, missing and filled surfaces (95% CI 16-33%). ↩