Fluoride is Safe & Effective

If you spend any time on the Internet, it’s easy to find a lot of scary information about fluoride and why you shouldn’t let your kids get any.  Speaking as a professional, however, I’d like to reassure you that NONE of that scary information is actually correct, and that fluoride in appropriate doses is one of the safest and most effective means of preventing tooth decay available.  It saddens me to see both children and adults who’ve been denied these benefits because of myths and misinformation, because those patients almost universally have many more cavities than patients who follow long-proven recommendations.  And since the American Academy of Pediatric Dentists recently released new guidelines, this is a good time to review, as there have been some changes.

Current Recommendations for Dental Fluoride for Children

SBPBlogFluoridePlease ensure your infant and child receive no more than the recommended amount of toothpaste.  This is for the same reasons that children should NOT be allowed any fluoride-containing mouth rinses before the age of 6: infants and toddlers can’t control their swallowing reflex so as to not swallow the toothpaste or rinse.  Eating or drinking too much fluoride can result in a couple problems (see further down the page for details).


How Does Fluoride Work on Your Teeth?

While it has long been thought that fluoride that is drunk or eaten helps to harden teeth, more recent research shows that the main effect is by coating the teeth and being absorbed.  This is why the AAP now recommends starting fluoride toothpaste when the first tooth shows through; it’s also one reason that fluoride supplements are now rarely recommended.

Basically, enamel is a mineral matrix, mostly made up of hydroxyapatite, which itself is composed of calcium and phosphate.  The way that fluoride works on enamel is kind of complicated, but if you want to learn more, Wikipedia covers it well here: Tooth Enamel and Remineralization.  In simple terms, when fluoride is added, it makes hydroxyapatite harder and more resistant to acid breakdown.

You can read how the benefits of fluoride were discovered.

Your teeth are exposed to fluoride in the following ways:

  • Fluoridated beverages and foods
  • Toothpaste
  • Mouthrinses
  • Fluoride varnishes (dentists and pediatricians)

fluoride varnish to protect teeth from cavitiesIn most dental offices today, the recommended method of applying fluoride is called a fluoride varnish.  Unlike those yucky trays filled with a fluoride foam that sat in your mouth for a minute that older generations had to endure, a varnish is a thick paste that is quickly painted onto the teeth.  It’s sticky enough to stay in place and allow fluoride to be absorbed by the teeth for up to 30 minutes, while still at a safe level that children can swallow it without risk.

What Are Safe Levels of Fluoride and What’s Too Much?

According to current FDA recommendations, the ideal concentration of fluoride in water is a mere 0.7 mg per liter, or 2.66 mg per gallon.1  Most toothpastes available in the USA currently contain 1,000 ppm or 30mg/oz.2 But how much is that in practical terms, and how much would you need to eat or drink to reach a toxic dose?  Fortunately, it is EXTREMELY difficult to do this.

*For anyone following the comments, I have made several adjustments to my initial statements based on additional information.  It has been challenging to find consistent data and sources; in addition, the continued use of pounds and ounces in the USA have required a lot of conversions to and from the metric system.  If you find additional errors, please point them out and provide references so that I can verify them.

  • An 8oz (.236 liters) glass of fluoridated water contains about 0.000166 grams of fluoride
    • This means you need to drink approximately 30,000 (THIRTY THOUSAND) 8 ounce glasses of water to reach a toxic dose
    •  This is equivalent to 5 liters per kg, or 2.5 gallons per pound of body weight
    • In other words, you will die of water poisoning long before you reached the toxic dose of fluoride
  • The LD50 (median dose that kills 50% of those who take it) for sodium fluoride = 52mg/kg3
  • A large tube of toothpaste in the USA is 6.4oz (181 grams)
    • A typical 1 year old 22lb (10kg) child would have to eat nearly THREE tubes (10kg x 52mg/kg = 520/181 = 2.87 tubes)
    • A typical 3 year old 32lb (20kg) child would have to eat nearly SIX tubes (20kg x 52mg/kg = 1040/181 = 5.75 tubes)
    • A typical 155lb (70kg) adult would have to eat up to TWENTY tubes (70kg x 52mg/kg = 3640/181 = 20.11 tubes).
    • You would throw up from that much toothpaste long before reach that level.4
  • The greatest danger to infants and toddlers certainly come from mouthrinses, which can be drunk very quickly.
    • That 1yo child would have to drink 7oz (215ml)
    • The 3yo child would have to drink 14oz (430ml)
    • Of course, given that many mouthrinses today contain up to 20% alcohol, the child would equally be in danger of intoxication and alcohol poisoning.

As you can see, it is basically impossible to take in enough fluoride to be poisoned by fluoridated water, and for large children or adults, it would be equally difficult to reach a toxic level through toothpaste.  However, it does demonstrate the importance of keeping toothpaste out of the reach of small children, who could still eat enough to make themselves quite sick.  But really – do you think any child would EVER be able to eat even 1-2 complete tubes of toothpaste?  They’d get sick long before finishing.

Calculations and references available here and here if you want to check for yourself.

One important item to remember: fluoride is normally found in groundwater, aquifers, reservoirs, well water, and even in ocean water.  In some areas, concentrations are high enough that the fluoride found in local water sources are high enough that no additional fluoride is needed, and, in fact, parents in such areas may need to filter their water to remove excess.  This is one real benefit of community water fluoridation, which ensures that no more than the maximum recommended dosage is in the water.

Measuring the Right Amount of Toothpaste

Charlotte family dentist describes how much toothpaste to use for children

Keep this graphic handy so you can determine if you are applying too much or too little toothpaste to your little one’s toothbrush.

What is Fluorosis, and Is It Bad?

what does fluorosis look like, and is it badGiven that it’s almost impossible to reach a really toxic dose with fluoride, why do we recommend keeping the dosage so small?  It’s because of a condition called fluorosis, which is what happens when too much fluoride is swallowed by a child under the age of 8 (give or take a couple years).  The reason there’s an age limit to it is that fluorosis can only happen while the permanent teeth are developing under the gums.  Once the enamel is fully formed, it’s no longer possible for fluorosis to occur.  Fluorosis is mostly a cosmetic problem though.

Why Doesn’t Dental Insurance Cover Fluoride for Adults?

Honestly, this is the one question to which I don’t have a good answer, because the fact that they don’t, makes absolutely ZERO sense to me.  Since it’s good for preventing tooth decay, you’d think they would cover it for adults, too.  After all, almost all insurance companies are for-profit, and you’d think they would cover everything that would reduce the amount they pay out.  So the only answer I can give is the one from my gut: they don’t cover it simply because they’ve never covered it.  You know – since it’s always been that way, why should they change?

Admittedly, most adults don’t need fluoride treatment, because their teeth are already fully formed, and fluoride is most beneficial when the teeth are still growing in and developing.  Adults with good home care and healthy diet that is low in sugars and acids, with little or no history of dental decay, really wouldn’t benefit from additional fluoride.  However, for those adults with a long history of cavities, you should definitely talk to your dentist about getting fluoride varnish treatments on a regular basis, as it can still help to reduce your risk of new cavities, even if your insurance doesn’t cover it.  At only $15-50 per treatment (mostly depending on your location), it’s one of the cheapest and most effective ways to cut down on your dental bill.

Common Myths About Fluoride

Now Or Later Signpost Showing Delay Deadlines And UrgencyUnfortunately, there are a lot of myths on the web about fluoride, and some of them even seem to come from reputable sources, so how do you know what’s real and what’s bogus?  I was going to write a nice list, but in my research, I came upon a website that has already done all the work, including debunking the nonsense.  It even includes links to excellent scientific research for those who want to dig deep into the data.  So here you go: Fluoride Myths and Conspiracies Debunked.

By | 2017-06-09T20:29:42+00:00 February 19th, 2015|Family dentistry, Taking Care of Your Teeth|25 Comments

About the Author:

My profession and passion are one and the same: I’ve been a Charlotte dentist since 1999, and if you’re in need of a dental office, we’ll gladly welcome you. We offer most of the most modern technology available and a unique and broad combination of services. We know the dentist isn’t the most fun place to be, but we try to make it the best possible, and since I truly love my job, we aim to offer the best dental care possible.

  • johndmac

    Breaking News: New study shows that fluoridated water lowers adult IQ.

    A mega-analysis of US dentists found that those who drink fluoridated water had 21% more IQ loss than dentists who drink non-fluoridated water.

    The number of IQ points that were decayed, missing, or forfeited (DMF) was 3.4 for fluoridated dentists and 2.8 for non-fluoridated dentists.

    Fairy T, Bunny E, et al. 2015. A mega-analysis of US dental practitioner beverage preferences. J Oral Obsession. Apr1;35(2):561-568. Epub ahead of print.

    • OH.MY.GAWD! I am so DYING laughing! “J Oral Obsession”


  • Amy G

    good lord. who is doing the running the numbers here? no wonder people roll their eyes when dentists call themselves ‘scientists’.

    • Ahhhh, Amy, why don’t you demonstrate the correct math? If I’m incorrect, I will gladly admit it and make corrections, but I did spend a fair amount of time trying to be as accurate as possible and had the numbers checked by non-dentists, too.

      • Amy G

        i’ll page ‘dr’ slott as he is the one who ‘corrects mounds of misinformation.. posted all over the internet’.

        • Oh that’s weak, Amy. If it’s so obvious, please go ahead and do it yourself. Please demonstrate your expertise.

          • Amy G

            first problem is here: “Most toothpastes available in the USA currently contain 1.0 ppm”

            only off by about 999 ppm.

            stick to your fluorosis repair business. leave the math to real scientists.

            • You know what, Amy? You are correct about that, and I am correcting it. And just to make sure, since that was incorrect, I will double-check all of my numbers and proof them. If there are others, please point them out, and I will fix those as well. I have no problem with that, as long as I can verify them.

              • johndmac

                0.7 mg per liter is not a dose. It is a concentration or level.

                • Oops! Thank you, and correction made. 🙂

                  • johndmac

                    You say: “The ‘pea-sized’ amount of toothpaste recommended for children under 3yo = 0.00025 grams of fluoride.”

                    But the AAP says it should be a “smear” that contains 0.1 mg of fluoride.

                    • Yeesh – I thought I had done a good job of proof-reading, but I clearly missed a few things. This one, in particular, is silly, because I had just written about the “smear” a little above that! Anyway, I am trying to find where it says that the smear = 0.1mg fluoride, do you have a link?
                      I have tried finding the estimated weight of even a pea-sized amount of toothpaste but can’t. I checked on the weight of a single green pea and found approximately 0.1 – 0.36 gm, but a smear of toothpaste can’t possibly even be that much.
                      Let’s assume for the sake of argument that a smear of toothpaste = 0.1gm = 10mg (still seems high though)
                      10mg = 0.00035oz
                      If 30mg F is in 1 oz, then in .00035oz there will be 0.01mg F = 0.00001 grams, which is even lower than I originally wrote in the article.
                      Feel free to double-check that, but if this is correct, it would require eating even more toothpaste than I initially estimated.
                      We can make the calculation a lot easier, though. Assuming we take the ADA maximum amount of fluoride of 276mg per 6.4oz tube, you would have to eat EIGHTEEN tubes of toothpaste to reach the 5gm toxic dose.

                    • johndmac

                      Here’s the source: Fluoride toothpaste use for young children, American Dental Association Council on Scientitic Afairs, February 2014. http://jada-plus.com/content/145/2/190.full.pdf

                      “Figure. The toothbrush on the left shows a smear of toothpaste (0.1 milligram of fluoride) and the one on the right a pea-sized amount (0.25 mg of fluoride).”

                      A smear therefore has 0.0001 gram of fluoride.

                    • Ahhhh, thank you, I missed that one. I was surprised that I couldn’t find that on the AAP website very easily.

            • BTW Amy – what the heck is a “fluorosis repair business?” Do you have any clue how little I ever see patients with real fluorosis? Basically……….NEVER. Like maybe 1-2 people in my 17 year career.

  • Susanna Barbee

    Very interesting. Although that warning label on the back of toothpaste boxes is very, very scary.

    • Susanna, you’re right, it is, and I personally think it is overblown, but when you consider how lawsuit-happy many Americans are, it kind of makes sense, right?

      It’s kind of the same thing with ibuprofen. Looking at the bottle, it kind of scares you about taking any more, but realistically, you can take up to 800mg of ibuprofen at a time (better on a full stomach) as long as you stretch it out to SIX hours apart. If you do that, you still just reach the maximum safe dose per day. But if that were on the bottle and everyone started taking 800mg and forgot to spread the doses further apart, you could do some serious damage to your liver in a few days. So they put what they KNOW is a safe dose, being ultra-conservative so that even if people go over it a bit, they’re still well within the safe limits.

      I think the main point to remember is just how hard it would be to eat an entire tube of toothpaste. You’d probably get sick, but it wouldn’t be the fluoride, and it wouldn’t really be “poisonous,” just totally disgusting.

  • 1875

    Case histories and peer reviewed research shows that fluoride can cause harm even at
    low levels. Some people can experience toxicity symptoms from drinking fluoridated water or using fluoride tablets. Symptoms include neurological problems, headaches, skin irritation, gastrointestinal pain, and symptoms (Waldbott 1956, 1958, Feltman 1956, Feltman and Kosel 1961, Grimbergen 1974,Petraborg 1977, Spittle 2008,). Patients were often unaware that their drinking water contained fluoride. Symptoms improved with avoidance of fluoridated water and returned with consumption of fluoridated water or with experimental challenge with fluoride and confirmed by double blind testing. Doctors aren’t
    trained to suspect fluoride, so patients may be treated for side effects when all that is needed, is avoidance of fluoridated water. These side effects experienced by some people at low levels are the same as those that are experienced by most people at high levels of exposure indicating that the symptoms are toxicity or poisoning symptoms.(Confirmed in the Physicians’ Desk Reference) This makes sense when you consider that the fluoride ion is more toxic than lead and only slightly less lethal than arsenic (Clinical Toxicology of
    Commercial products, LD50 data – 1984), yet only 10 ppb (0.01 ppm) maximum is allowed for lead and arsenic in our drinking water. Now with fluoride they are adding 700 to 1000 ppb (0.7 to 1.0 ppm). There are going to be problems. Fluoride is the active ingredient in many rat poisons and insecticides. Do your own research.
    The Feltman and Kosel study was published in the Journal of Dental Medicine and
    received funding from the US Public Health Service, Department of Health
    Education and Welfare, Washington DC.

    “Fluorine and fluorides can act as direct cellular poisons by interfering with calcium
    metabolism and enzyme mechanisms.” (Handbook of Poisoning: Prevention,
    Diagnosis and Treatment, 11th Edition, 1983.)

    “Fluoride is an enzyme poison, in the same class as cyanide, oxalate, or azide … it is
    capable of a very wide variety of harmful effects, even at low doses.”
    (James B. Patrick, Ph.D., antibiotics research scientist.)

    “Yes, fluoride is an (enzyme) inhibitor. You are right in the implication that when it comes to certain patients, it is important that they do not have fluoride in the water.” (Dr. Harold Loe, National Institute of Dental Research,to a subcommittee of the House Appropriations Committee, 1989.)

    • “Do my own research” is the classic cry of someone who really has none. I’ve already provided far more evidence and links to reputable research than you have and have done PLENTY of research. I also noted that of all the articles you posted, only 1 was even from the last 20 years, and most of them were are 40-50 years old. Curious how you seem to have ignored all the other studies that are newer and of better quality.

      In point of fact, fluoride is NOT used in rat poison these days, but apparently you’re unable to do any research on that. Why don’t you find the ingredient list of any rat poison and post it? But even if it is, that is a fallacious argument. As I clearly pointed out in my article – you can die of water poisoning/overdose, and water is in everything. IT’S ABOUT THE DOSE. Are you going to stop drinking water since you can die from too much? Of course not, so please stop using nonsensical and meaningless statements. It makes you sound like the Food Babe.

      • 1875

        Valid scientific evidence doesn’t go go out of date. The fluoride ion is the same as it was 40-50 years ago .Please provide the newer studies you are referring to – studies involving individual testing and monitoring – not opinions reviews or endorsements. You’ve obviously missed the point that side effects can be experienced at levels found in fluoridated water so it’s pointless carrying on about dying form too much water. Thanks.

        • Are you serious? Really? For someone who asks others to “do your research,” you clearly haven’t done yours. I’ve already provided PLENTY of links within the article that you can follow for a wealth of information – why don’t you follow them because I’ve already provided the answers.

      • Crystal

        I understand this discussion was from two years ago but I have some concerns on fluoride. Here is a site that has references. http://articles.mercola.com/sites/articles/archive/2012/08/07/effects-of-fluoride-to-children.aspx I have more if need be and there are other studies that aren’t even five yrs old. I hope you can diminish my concerns. Do you still stand by your beliefs on fluoride or has it changed since then? Pls get back to me as soon as possible thank you

        • Crystal, with all due respect, Mercola is a quack and is utterly unqualified to speak on the topic. I have provided more than enough resources already to refute every claim that he and others like him make. As I’ve said, individual studies, or even small groups of studies, are inadequate to overcome the overwhelming scientific consensus of the last 100 years unless they are extraordinarily well done and provide some entirely new method of testing and understanding, that can then be validated by others.

          As for a specific critique of the Harvard study, there have been many, and the single most important thing wrong with it is that the study was done in China, in areas where the natural fluoride levels in water were 3-5x higher (that means 300-500% higher) than what we allow in the USA.