June 13, 20253 min readCould Iran Have Been Close to Making a Nuclear Weapon? Uranium Enrichment ExplainedWhen Israeli aircraft recently struck a uranium-enrichment complex in the nation, Iran could have been days away from achieving “breakout,” the ability to quickly turn “yellowcake” uranium into bomb-grade fuel, with its new high-speed centrifugesBy Deni Ellis Béchard edited by Dean VisserMen work inside of a uranium conversion facility just outside the city of Isfahan, Iran, on March 30, 2005. The facility in Isfahan made hexaflouride gas, which was then enriched by feeding it into centrifuges at a facility in Natanz, Iran. Getty ImagesIn the predawn darkness on Friday local time, Israeli military aircraft struck one of Iran’s uranium-enrichment complexes near the city of Natanz. The warheads aimed to do more than shatter concrete; they were meant to buy time, according to news reports. For months, Iran had seemed to be edging ever closer to “breakout,” the point at which its growing stockpile of partially enriched uranium could be converted into fuel for a nuclear bomb. (Iran has denied that it has been pursuing nuclear weapons development.)But why did the strike occur now? One consideration could involve the way enrichment complexes work. Natural uranium is composed almost entirely of uranium 238, or U-238, an isotope that is relatively “heavy” (meaning it has more neutrons in its nucleus). Only about 0.7 percent is uranium 235 (U-235), a lighter isotope that is capable of sustaining a nuclear chain reaction. That means that in natural uranium, only seven atoms in 1,000 are the lighter, fission-ready U-235; “enrichment” simply means raising the percentage of U-235.U-235 can be used in warheads because its nucleus can easily be split. The International Atomic Energy Agency uses 25 kilograms of contained U-235 as the benchmark amount deemed sufficient for a first-generation implosion bomb. In such a weapon, the U-235 is surrounded by conventional explosives that, when detonated, compress the isotope. A separate device releases a neutron stream. (Neutrons are the neutral subatomic particle in an atom’s nucleus that adds to their mass.) Each time a neutron strikes a U-235 atom, the atom fissions; it divides and spits out, on average, two or three fresh neutrons—plus a burst of energy in the form of heat and gamma radiation. And the emitted neutrons in turn strike other U-235 nuclei, creating a self-sustaining chain reaction among the U-235 atoms that have been packed together into a critical mass. The result is a nuclear explosion. By contrast, the more common isotope, U-238, usually absorbs slow neutrons without splitting and cannot drive such a devastating chain reaction.On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.To enrich uranium so that it contains enough U-235, the “yellowcake” uranium powder that comes out of a mine must go through a lengthy process of conversions to transform it from a solid into the gas uranium hexafluoride. First, a series of chemical processes refine the uranium and then, at high temperatures, each uranium atom is bound to six fluorine atoms. The result, uranium hexafluoride, is unusual: below 56 degrees Celsius (132.8 degrees Fahrenheit) it is a white, waxy solid, but just above that temperature, it sublimates into a dense, invisible gas.During enrichment, this uranium hexafluoride is loaded into a centrifuge: a metal cylinder that spins at tens of thousands of revolutions per minute—faster than the blades of a jet engine. As the heavier U-238 molecules drift toward the cylinder wall, the lighter U-235 molecules remain closer to the center and are siphoned off. This new, slightly U-235-richer gas is then put into the next centrifuge. The process is repeated 10 to 20 times as ever more enriched gas is sent through a series of centrifuges.Enrichment is a slow process, but the Iranian government has been working on this for years and already holds roughly 400 kilograms of uranium enriched to 60 percent U-235. This falls short of the 90 percent required for nuclear weapons. But whereas Iran’s first-generation IR-1 centrifuges whirl at about 63,000 revolutions per minute and do relatively modest work, its newer IR-6 models, built from high-strength carbon fiber, spin faster and produce enriched uranium far more quickly.Iran has been installing thousands of these units, especially at Fordow, an underground enrichment facility built beneath 80 to 90 meters of rock. According to a report released on Monday by the Institute for Science and International Security, the new centrifuges could produce enough 90 percent U-235 uranium for a warhead “in as little as two to three days” and enough for nine nuclear weapons in three weeks—or 19 by the end of the third month.

Artificial intelligence has sent demand for electricity skyrocketing in the U.S. after years of virtually zero growth. That has sent Big Tech companies scrambling to secure generating capacity for their data centers. For many, that has meant turning to nuclear fission. The power source has been experiencing a resurgence in the last few years following decades of plant closures. (Fission, used in all current nuclear plants, is distinct from fusion, the still-experimental approach to getting power from atoms that, while attracting investors, has yet to produce more electricity than it consumes.) For tech companies, part of the appeal of fission is a stable, predictable source of power that flows 24/7, giving their data centers the potential to run computing loads whenever they require it.  But another part of the appeal lies in new reactor designs that promise to overcome the shortcomings of existing nuclear power plants. Where old power plants were built around massive reactors that could generate over 1 gigawatt of electricity, new small modular reactor (SMR) designs see multiple modules deployed alongside each other to meet a range of needs.  SMRs rely on mass manufacturing to bring costs down, but to date, no one has built one in the U.S. Still, that hasn’t kept Amazon, Google, Meta, and Microsoft away from the table. They’ve either signed agreements to buy power from nuclear startups or invested in them directly — or both. Here are the nuclear fission startups backed by Big Tech. Kairos Power Kairos Power received a vote of confidence from Google when the search giant promised to buy around 500 megawatts of electricity by 2035, with the first reactor targeted to come online by 2030. Techcrunch event Join us at TechCrunch Sessions: AI Secure your spot for our leading AI industry event with speakers from OpenAI, Anthropic, and Cohere. For a limited time, tickets are just $292 for an entire day of expert talks, workshops, and potent networking. Exhibit at TechCrunch Sessions: AI Secure your spot at TC Sessions: AI and show 1,200+ decision-makers what you’ve built — without the big spend. Available through May 9 or while tables last. Berkeley, CA | June 5 REGISTER NOW The company’s small modular reactors rely on molten fluoride salt for cooling and to transport heat to a steam turbine. The salt’s high boiling point means that the coolant doesn’t need to be kept at high pressure, which should improve operating safety. The reactors contain fuel pebbles coated in carbon and ceramic shells, which should be strong enough to withstand a meltdown. The Alameda-based startup has received a $629 million award from the U.S. government, including $303 million from the Department of Energy. In November 2024, Kairos received approval from the U.S. Nuclear Regulatory Commission to commence construction on two reactors in Tennessee. At 35 megawatts, the test units will be smaller than Kairos’ eventual commercial reactors, which are expected to generate 75 megawatts each. Oklo Oklo is another SMR company targeting the data center world — no surprise given that it was backed by OpenAI CEO Sam Altman, who also took the nuclear startup public via a reverse merger with his special purpose acquisition vehicle, AltC, in July 2023. Altman served as chairman of Oklo until April, when he stepped down as OpenAI began negotiating with Oklo for an energy supply agreement. DCVC, Draper Associates, and Peter Thiel’s Mithril Capital Management are among the startup’s previous investors. Cooled by liquid metal, Oklo’s reactor is based on an existing U.S. Department of Energy design that’s intended to reduce the amount of nuclear waste that results from regular operations. Still, Oklo’s path hasn’t been a smooth one. The company’s first license application was denied in January 2022. Oklo has said it will resubmit the application sometime in 2025. But that hasn’t stopped the company from landing a deal to supply data center operator Switch with 12 gigawatts by 2044. Saltfoss Like Kairos, Saltfoss, formerly known as Seaborg, also wants to build SMRs cooled by molten salt. But unlike Kairos and others, it envisions placing two to eight of them on a ship to create what it calls a Power Barge. The startup has raised nearly $60 million, including a $6 million seed round that included investments from Bill Gates, Peter Thiel, and Unity co-founder David Helgason, according to PitchBook. Satlfoss has an agreement with Samsung Heavy Industries to build the ships and the Satlfoss-designed reactors. TerraPower Founded by Bill Gates, TerraPower is building a larger reactor, called Natrium, which is cooled by liquid sodium and features molten salt energy storage. The company broke ground on the first power plant in June 2024 in Wyoming. The Natrium design calls for the reactor to generate 345 megawatts of electricity. That’s smaller than other new nuclear plants today but larger than most SMR designs.  But Natrium has a trick up its sleeve with its molten salt heat storage system. Since nuclear reactors operate best at a steady state, the Natrium reactor can continue breaking atoms when demand is low, and the extra energy is stored as heat in a vat of molten salt, which can be drawn upon later to generate electricity. Investors include Gates’ Cascade Investment fund, Khosla Ventures, CRV, and ArcelorMittal. X-Energy X-Energy landed a hefty $700 million Series C-1 last year led by Amazon’s Climate Pledge Fund. At the same time, the SMR startup announced two development agreements that would see the deployment of 300 megawatts of new nuclear generating capacity in the Pacific Northwest and Virginia. The company’s high-temperature, gas-cooled reactors buck recent trends in the U.S. and Europe, where the design has been shunned in favor of other approaches. The company’s Xe-100 reactor is expected to generate 80 megawatts of electricity. Helium gas flows through the reactor’s 200,000 billiard ball-sized fuel “pebbles,” absorbing heat to spin a steam turbine. 

Feno, the “smart electric toothbrush,” promised to take a two-minute toothbrushing routine and bring it down to 30 or even 20 seconds by swabbing each of my teeth at once. The Feno Smartbrush makes brushing faster, but in exchange it requires you to shove an entire mouthpiece in your piehole twice a day just to cut down on a total of three minutes of brushing time. If there is one thing to take away from this review, it’s that even if tech works, it doesn’t necessarily mean it’s better than what we already have. The “toothbrush” has been at the side of my bathroom sink for more than three weeks. It has technically saved me time. I would even go as far as to say it may do the job of a regular toothbrush with less time to get there. Still, given the choice, I would rather reach for my non-motorized, dentist-recommended toothbrush—if only because I know it works. After consulting with the companies and non-affiliated dentists, I’m more bemused that the Feno exists at all. This is a device that costs $300 for the “Founder’s Edition” bundle. The company recently said it would increase the price to $400, blaming tariffs for the rising cost. As the time of this publishing, that new price hasn’t yet materialized. The box comes with three canisters of brand-specific Feno Foam toothpaste. After you run out, you’ll need to spend $30 to get an extra three canisters. Feno also recommends replacing the mouthpiece every three months, costing another $30. Feno Smartbrush It may brush all your teeth for quicker cleans, but its too much of an unknown to recommend. Pros Cons My dentist gave me my last manual toothbrush for free. A tube of toothpaste was $5. Despite the price, the company behind the smart toothbrush has one compelling pitch. If people were honest with themselves, most folks do not do the recommended amount of brushing. I fit into that camp for most of my life, until the point I went to my dentist and found I needed to have multiple caps on my molars, requiring I spend a hefty chunk of change for the privilege of having my teeth ground down to nubs. Since then, I’ve become very sensitive to the state of my pearly whites. I try to do the full two minutes of brushing and floss every day, but the Feno is supposed to help by shortening the brushing time and helpfully counting you down with an on-screen timer. My dentist was skeptical about the device’s claims, especially whether it was offering proper back-and-forth brushing technique. The American Dental Association has a Seal of Acceptance tested by the organization for products that are recommended by dentists. Neither Feno’s brush nor special toothpaste are on that list of products with the ADA seal. All I have to go on is Feno’s own claim that it’s doing what it needs to do to clean my teeth and remove plaque. For cleaning, the device makes use of pressure sensors alongside the mouthpiece’s 18,000 bristles, which Feno claims can hit 250 strokes per tooth in 20 seconds. It’s using a sweeping motion along the teeth, which dentists recommend when brushing, but there’s no published science to say the Feno is particularly better than other, similar devices. Feno told me the company has scientific research pertaining to how effective the device is, but it’s pending scientific review and won’t be available until some unknown date. © Adriano Contreras / Gizmodo © Adriano Contreras / Gizmodo © Adriano Contreras / Gizmodo © Adriano Contreras / Gizmodo Feno revels in Silicon Valley startups’ worst habits. Every time you turn it on, the smart toothbrush bombards you with a QR code to download an app for all its controls, rather than including those on-device. The Feno toothbrush can incite the same gag reflex you know if you’ve ever played a contact sport requiring a mouth guard. The device is big enough that you have to open wide to fit the whole thing in at once. Brushing with the Feno is not an entirely passive experience, either. Feno’s founder, Dr. Kenny Brown, told me his company recommends moving the brush side to side while the mouthpiece actuates. On its highest settings, the Feno rattled my jaw and made my entire head shake like a marionette piloted by a mad puppeteer. With those speeds, I could feel the mouthpiece rubbing the inner cheek raw. At normal speeds, the Feno was uncomfortable but still usable without any pain. Feno also advises some gums may bleed if you haven’t been doing proper brushing technique for too long, but I didn’t find the bristles were any more abrasive to my gums than a regular toothbrush. The device running on default settings for 30 seconds seems engineered for most mouths. The company claims its device works with regular toothpaste, but when I plastered some gel to the bristles and stuck it in my mouth, it resulted in a sludgy mess at the bottom of the mouthpiece that took far longer to clean than the typical quick rinse. The foam toothpaste doesn’t leave your mouth full of the typical minty taste of fluoride and baking soda you normally associate with the feel of a clean mouth. As a point in favor of the Feno, that minty-fresh taste in your mouth isn’t actually indicative of clean teeth, according to Dr. Edmond Hewlett, a professor at UCLA’s School of Dentistry and a consumer advisor for the American Dental Association. Brown told me the company plans for updated toothpaste that adds a lingering minty taste in the mouth, as apparently I wasn’t the only one who spoke up on that lack of “clean” feeling. © Adriano Contreras / Gizmodo © Adriano Contreras / Gizmodo Knowing my dentist appointments are near for even more fillings, the Feno would not only need to be good, but even better at cleaning my teeth than the typical electric brush. Even if I felt it may be hitting all my teeth, the device didn’t leave me feeling clean, not least because I had no control over it. Even if the Feno full-mouth toothbrush wasn’t uncomfortable, wasn’t expensive, didn’t require an app, and worked well with regular toothpaste, it would still be hard to make any claim it results in better cleaning than your regular $7 toothbrush you buy from any local pharmacist. Using the smart toothbrush, you can’t tell what’s happening to your teeth. You can’t tell if it’s hitting all the nooks and crannies. That’s going to be a concern when everybody’s set of teeth is different. The Feno is supposedly designed so that all its bristles hit all different kinds of teeth at the correct 45-degree angle to the gums, but what really matters is if it adds anything to your brushing routine. “The critical question of any device like this is if it’s better than a toothbrush,” Hewlett told me. “It’s clear that using a toothbrush properly is one of the most effective things a person can do themselves to preserve their teeth.”

New contact lenses can provide infrared visionolga Yastremska/Alamy Contact lenses have enabled people to see beyond the visible light range, picking up flickers of infrared light even in the dark – or with their eyes closed. The lenses contain engineered nanoparticles that absorb and convert infrared radiation – specifically, a near-infrared wavelength range of 800 to 1600 nanometres – into blue, green and red light visible to the human eye. That is the same trick night-vision devices use to help people see in the dark, but the contact lenses weigh much less and require no additional power. Advertisement “The contact lenses would provide military personnel with discreet, hands-free night-vision capabilities that overcome the limitations of bulky night-vision [goggles or scopes],” says Peter Rentzepis at Texas A&M University, who has done related research applying the same nanoparticles – sodium gadolinium fluoride, ytterbium and erbium – to eyeglass lenses. The new wearables, developed by Yuqian Ma at the University of Science and Technology of China and his colleagues, don’t provide detailed night vision yet. That is because they can pick up only “high-intensity, narrowband LED” light sources, says Rentzepis, rather than lower levels of infrared light from ambient sources. “It’s an audacious paper but, using just the contact lens, you wouldn’t be able to read a book in the infrared, or navigate down a dark road,” says Mikhail Kats at the University of Wisconsin-Madison, who was not involved in the research. Receive a weekly dose of discovery in your inbox. Sign up to newsletter Instead, in tests on humans and mice, the contacts converted a normally invisible flash of infrared light into what Kats says should be a “big colourful blob of visible light”. Those blobs had uses, however. For example, Ma and his colleagues varied the frequency, number and colour of different light flashes to encode and transmit letters of the alphabet. This follows a previous study in which the researchers injected nanoparticles directly into the eyes of mice to provide infrared vision. The wearable contacts represent a “safer and more practical approach for human applications”, says Rentzepis. But they still come with potential health and safety risks, he notes, such as heat exposure from the light-conversion process and possible nanoparticle leakage into eye tissue. Journal referenceCell DOI: 10.1016/j.cell.2025.04.019 Topics:

This is today’s edition of The Download, our weekday newsletter that provides a daily dose of what’s going on in the world of technology. Inside the story that enraged OpenAI —Niall Firth, executive editor, MIT Technology Review In 2019, Karen Hao, a senior reporter with MIT Technology Review, pitched me a story about a then little-known company, OpenAI. It was her biggest assignment to date. Hao’s feat of reporting took a series of twists and turns over the coming months, eventually revealing how OpenAI’s ambition had taken it far afield from its original mission.The finished story was a prescient look at a company at a tipping point—or already past it. And OpenAI was not happy with the result. Hao’s new book, Empire of AI: Dreams and Nightmares in Sam Altman’s OpenAI, is an in-depth exploration of the company that kick-started the AI arms race, and what that race means for all of us. This excerpt is the origin story of that reporting. This spa’s water is heated by bitcoin mining At first glance, the Bathhouse spa in Brooklyn looks not so different from other high-end spas. What sets it apart is out of sight: a closet full of cryptocurrency-­mining computers that not only generate bitcoins but also heat the spa’s pools, marble hammams, and showers.  When cofounder Jason Goodman opened Bathhouse’s first location in Williamsburg in 2019, he used conventional pool heaters. But after diving deep into the world of bitcoin, he realized he could fit cryptocurrency mining seamlessly into his business. Read the full story. —Carrie Klein This story is from the most recent edition of our print magazine, which is all about how technology is changing creativity. Subscribe now to read it and to receive future print copies once they land. The must-reads I’ve combed the internet to find you today’s most fun/important/scary/fascinating stories about technology. 1 Nvidia wants to build an AI supercomputer in Taiwan As Trump’s tariffs upend existing supply chains. (WSJ $)+ Jensen Huang has denied that Nvidia’s chips are being diverted into China. (Bloomberg $) 2 xAI’s Grok dabbled in Holocaust denialThe chatbot said it was “skeptical” about points that historians agree are facts. (Rolling Stone $)+ It blamed the comments on a programming error. (The Guardian) 3 Apple is planning to overhaul Siri entirelyTo make it an assistant fit for the AI age. (Bloomberg $) 4 Dentists are worried by RFK Jr’s fluoride banParticularly in rural America. (Ars Technica)+ Florida has become the second state to ban fluoride in public water. (NBC News) 5 Fewer people want to work in America’s factoriesThat’s a problem when Trump is so hell-bent on kickstarting the manufacturing industry. (WSJ $)+ Sweeping tariffs could threaten the US manufacturing rebound. (MIT Technology Review) 6 Meet the crypto investors hoping to bend the President’s earThey’re treating Trump’s meme coin dinner as an opportunity to push their agendas. (WP $)+ Many of them are offloading their coins, too. (Wired $)+ Crypto bigwigs are targets for criminals. (WSJ $)+ Bodyguards and other forms of security are becoming de rigueur. (Bloomberg $) 7 How the US reversed the overdose epidemicNaloxone is a major factor. (Vox)+ How the federal government is tracking changes in the supply of street drugs. (MIT Technology Review) 8 Chatbots really love the heads of the companies that made them And are not so fond of the leaders of its rivals. (FT $)+ What if we could just ask AI to be less biased? (MIT Technology Review) 9 Technology is a double-edged sword What connects us can simultaneously outrage us. (The Atlantic $) 10 Meet the people hooked on watching nature live streamsThey find checking in with animals puts their own troubles in perspective. (The Guardian) Quote of the day “People are just scared. They don’t know where they fit in this new world.” —Angela Jiang, who is working on a startup exploring the impact of AI on the labor market, tells the Wall Street Journal about the woes of tech job seekers trying to land new jobs in the current economy. One more thing How the Rubin Observatory will help us understand dark matter and dark energyWe can put a good figure on how much we know about the universe: 5%. That’s how much of what’s floating about in the cosmos is ordinary matter—planets and stars and galaxies and the dust and gas between them. The other 95% is dark matter and dark energy, two mysterious entities aptly named for our inability to shed light on their true nature.Previous work has begun pulling apart these dueling forces, but dark matter and dark energy remain shrouded in a blanket of questions—critically, what exactly are they?Enter the Vera C. Rubin Observatory, one of our 10 breakthrough technologies for 2025. Boasting the largest digital camera ever created, Rubin is expected to study the cosmos in the highest resolution yet once it begins observations later this year. And with a better window on the cosmic battle between dark matter and dark energy, Rubin might narrow down existing theories on what they are made of. Here’s a look at how. —Jenna Ahart We can still have nice things A place for comfort, fun and distraction to brighten up your day. (Got any ideas? Drop me a line or skeet ’em at me.) + Archaeologists in Canada are facing a mighty challenge—to solve how thousands of dinosaurs died in what’s now a forest in Alberta.+ Before Brian Johnson joined AC/DC, he sang on this very distinctive hoover (vacuum cleaner) ad.+ Wealthy Londoners are adding spas to their gardens, because why not.+ I must eat the crystal breakfast!

Pro-tooth decay RFK Jr’s plan to ban fluoride supplements will “hurt rural America,” dentists say In areas without fluoridated water, supplements are the only way to get adequate doses. Beth Mole – May 16, 2025 5:55 pm | 19 Credit: Getty | Flavio Coelho Credit: Getty | Flavio Coelho Story text Size Small Standard Large Width * Standard Wide Links Standard Orange * Subscribers only   Learn more This week, the US health department announced a plan to ban prescription fluoride supplements for children. These ingested fluoride products are dispensed at safe doses by doctors and dentists to prevent tooth decay in children who are unable to get adequate fluoride doses from community water systems—something that may become more common as more states and cities remove or ban fluoride from their water. Both the American Dental Association (ADA) and the American Academy of Pediatrics recommend fluoridating community water and advise prescribing fluoride supplements for children who do not get adequate fluoride dosages through their water. Nevertheless, the Department of Health and Human Services (HHS) under anti-vaccine advocate and conspiracy theorist Robert F. Kennedy Jr states without clear evidence that fluoride supplements harm children's microbiome and pose other health risks. The ADA pushed back strongly, telling Ars Technica in a written statement that the scientific studies the HHS references as evidence of harms "do not in fact demonstrate any harmful effects for the concentrations of fluoride prescribed by physicians and dentists." To support the alleged claim that fluoride harms the gut microbiome, HHS listed two review studies in its announcement. One review, published this year, concludes, "In humans, high doses potentially may be detrimental to the microbiome, whereas ≤ 2 mg/L [sodium fluoride] had positive effects." Community water systems are recommended to have a level of 0.7 mg/L. The other review, published in 2023, said that there wasn't enough human data to make any conclusions. In the announcement, FDA Commissioner Marty Makary was quoted as saying, "The best way to prevent cavities in children is by avoiding excessive sugar intake and good dental hygiene, not by altering a child’s microbiome. For the same reason that fluoride may kill bacteria on teeth, it may also kill intestinal bacteria important for a child’s health." “Harmful” While fluoride can kill bacteria, particularly at high levels, it's used in oral health to inhibit the demineralization of tooth enamel while enhancing the remineralization of tooth surfaces, the ADA clarifies. The best way to get fluoride is through drinking water, the ADA says. But supplements are a safe alternative if a child lives in an area without fluoridated water or if they mostly drink bottled water. Given rampant false and controversial claims about fluoride, more communities are now abandoning it. This week, Florida became the second state after Utah to ban fluoridation state-wide. "Yes, use fluoride for your teeth, that’s fine," Florida Gov. Ron DeSantis said at a news conference after signing the ban into law. "But forcing it in the water supply is basically forced medication on people. They don’t have a choice." ADA President Brett Kessler worries what children in places such as Utah and Florida will do to get adequate fluoride if the ban on supplements goes through. “In non-fluoridated communities, especially rural areas, fluoride supplements are the only chance for individuals to get the appropriate amount of fluoride to prevent tooth decay," Kessler said in the statement. The move will be "particularly harmful to the most vulnerable and those who lack access to care," he added. While Makary said that the FDA will conduct a safety review of  fluoride supplements, the conclusion seems to be foregone, with the HHS writing that it is already "initiating action to remove" the products. The ADA noted that places that have removed fluoride from drinking water, such as Calgary, Canada, and Juneau, Alaska, have seen increases in dental decay, particularly among children and low-income populations. "Proposals like this stand to hurt rural America, not make them healthier," Kessler said. Beth Mole Senior Health Reporter Beth Mole Senior Health Reporter Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes. 19 Comments

News Health & Medicine FDA plan to ban fluoride supplements baffles and alarms dental experts The move could mean further oral health decay, especially in rural areas Fluoride tablets and drops are prescribed to prevent tooth decay in places without fluoride in the water, such as U.S. rural communities. geckophotos/ iStock/Getty Images Plus By Tina Hesman Saey 9 seconds ago A decades-old dental health treatment may soon vanish in the United States. Access to fluoride supplements, prescribed to prevent cavities in children without access to fluoridated water, is now under threat from a controversial move by the U.S. Food and Drug Administration. The agency announced May 13 that it plans to remove fluoride products that can be ingested by children from the market, citing concerns about potential harm to gut microbes, links to thyroid disorders, weight gain and decreased IQ. Sign up for our newsletter We summarize the week's scientific breakthroughs every Thursday.