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Comment by dmarlow | Hacker News Reader

I stopped getting cavities when I stopped rinsing all of the fluoride away after brushing my teeth. If you wish to rinse, do so after a few minutes. I told this to my dentist and he said he wished that was more common knowledge, yet he's never mentioned it to me. Go figure.

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All of these posts have me wondering how commonplace cavities actually are. I stopped getting cavities in my preteen years, about 35 years ago. The only change I made was actually brushing my teeth regularly, which very young me always tried to avoid despite my parents' best efforts.

I'm sure my consumption of things like refined sugars has gone steadily down in that time, but not as part of a conscious effort. Being a kid in the 80s meant you ate a ton of crap :)

They're still pretty common, at least in the people I hang out in. You're very lucky you've not had any cavities since preteen. I've done allot to change my diet to strip out all sugars, refined carbs, acidic foods / drinks etc. But still get cavities.

It's a journey, sometimes a long one, to get to a spot with good oral heath. In my case, I had poor heath education. I didn't know what I didn't know. Like visiting the dentist is not equal to visiting a dental hygienist. Up until a few weeks ago, I had no clue what a dental hygienist was or if I should visit one. My dentist never recommended one, so I thought it wasn't needed. But I recently booked an apt with a dental hygienist at another practice, it was 100% needed.

From my understanding, a dental hygienist is more preventative work (and cleaning), while dentist is more the surgeon who does the fixing after an issue has occurred.

I learnt a tonne in my first ever dental hygienist visit. Basic things I wasn't doing for my oral heath. Like flossing... I never done it for years cos I thought it wasn't that big of a deal and cos I thought my teeth were to crammed together, but I learnt (and she showed me) that you can 100% floss my teeth and you defo should!

I wish some basic oral heath was taught in school, and that dental (at least 6 months/yearly checkups were free/govt funded), it's so important, and so expensive these days, even for a checkup.

It's especially tricky when you want to learn so much while at the dentist/hygienist, but know it's costing you $$$ so don't maybe ask everything. Personally the Teeth Talk Girl YouTube channel has helped me so much and gave me the courage to go back to the dentist (after not going for ~5 years).

I highly recommend the channel if you want to learn more on what good oral heath is. https://www.youtube.com/@TeethTalk

I stopped getting cavities when I started using fluoride-free toothpaste and filtered my water with reverse osmosis. But correlation is not causation and all, so it was probably due more to not eating sweets so much anymore, brushing and flossing properly and without fail twice a day, and maintaining a healthy immune system through sleep, exercise, and a good diet.

Fluoride is effective at remineralizing your enamel. Fluoride isn’t just for cavities.

What other uses does mineralized enamel have, aside from resisting attack by plaques? Honest question.

Plaque and tartar eat away at your enamel causing caries. Remineralizing is important to restore what has been taken away. So it’s not so much about resisting attack (I don’t believe fluoride fights bacteria) as much as reversing the attack.

You are much better off using nanohydroxyapatite for that, though; you can easily import such toothpastes from Japan via Amazon.

Source?

Not really a source, but this Dental Hygienist talks a bit about hydroxyapatite. Sounds like it could be of at least equal effectiveness. Though further studies are needed. https://youtu.be/kQAPEZaqwfY?t=63

Not OP but I have a family member who’s a specialized dentist who’s well regarded in the field and constantly harps on this kind of toothpaste over fluoride. I think fluoride is basically cheap and that’s all

Interesting. Hadn’t heard it it before, but at least according to this and it’s linked paper it’s roughly equivalent. What makes you say that you’re better off?

https://www.rdhmag.com/patient-care/article/14276225/nanohyd...

See also the bioactive glass compounds BioMin (fluoro calcium phosphosilicate) and NovaMin (calcium sodium phosphosilicate), which come in toothpastes that also include fluoride to cover all the bases.

https://ceramics.org/ceramic-tech-today/biomaterials/bioacti...

BioMin F is as effective as nanohydroxyapatite, and is less expensive than the Apagard nanohydroxyapatite toothpaste. (BioMin F is not yet available in the U.S. and needs to be imported.)

https://www.journalcra.com/sites/default/files/issue-pdf/317...

I use this stuff and I stopped getting cavities. Just one example obviously, but it was night and day better I think. It's a little pricey is all.

It's great for tooth sensitivity as well.

there is boka an American company. there are others as well, no reason to import from japan.

Perhaps, but how much of a difference does it really make? Your saliva remineralizes your enamel naturally. I've gone over 10 years without fluoride in my toothpaste or water and my teeth are in perfect condition, at least according to the dentist. So is the toxicity of fluoride worth some clearly minor and perhaps not even necessary improvement? I used large quantities of fluoride as a child, both in toothpaste and mouth washes, and still got 10 cavities.

Everyones teeth, diet etc are different. What works for you may not work for others.

Most people benefit significantly. That has been proven in study after study. The toxicity has not been, or it wouldn’t be widespread world wide. I’m glad your genetic makeup, diet, microbiome, etc is working out for you. That may or may not change with time.

The CDC says there’s a 25% reduction in cavities for children due to fluoride [1]. So it’s not like fluoride is only for cavity prevention, and perhaps your teeth would have been even worse without it.

[1] https://www.cdc.gov/fluoridation/index.html

I've gone through several studies and you are not representing the field fairly. There are many studies going both ways. It's far from a slam dunk consensus. Furthermore, there is absolutely no question that fluoride is toxic. It's just a question whether the amounts in water and toothpaste are enough to cause measurable negative effects.

Considering this, why don't we add things like B12, magnesium, and vitamin D to the water? They are all deficient in a large percentage of the population and cause severe problems, far worse than dental caries. The reason they are not is because it's not the business of the water supply to act as medicine for the general populace. It should come from individual products. You see fortified foods and vitamins, as well as fluoride toothpaste and mouth washes.

Could you cite your sources? I’m genuinely curious. There’s a lot of quackery out there on this since the tin foils love to accuse fluoride of somehow being a gov brain control method.

Of course fluoride is toxic at a certain level - so is water! The dose makes the poison. The question is if it’s a worthwhile trade off for society, and is it toxic at the levels used. It can’t be too toxic given the extremely large populations that have received it for decades without people dropping dead because of it. In fact life expectancy has only gone up since it’s introduction in 1945. Municipal water I believe is chlorinated as well, which in sufficient quantities is bad, but in small amounts is worth the trade off to kill the germs.

The US requires flour to be enriched with thiamin, riboflavin, niacin, folic acid, and iron. So there are other mandated ways to achieve vitamins in public health. My guess is water just isn’t an appropriate vector for those things for a variety of reasons, but that’s pure speculation. It’s an interesting question. On the other hand, I don’t believe you’ll naturally get fluoride anywhere else but injected into your water (or naturally occurring), so that’s probably a good deal why.

This is not a good faith argument to claim that fluoride and water are in the same class of substances when it comes to toxicity.

Also you are wrong that all flour in the US must be enriched. I have some unenriched flour on my shelf right now.

https://www.hsph.harvard.edu/news/features/fluoride-children...

The Harvard quoted study above looks at children in China in areas with high levels in groundwater .. high being of the order of 3-11 mg/litre.

The correlated 'damage' cited was of less than half an IQ point observed difference at the upper end of the high levels.

The fluoride doses used in water treatment (here in Australia) are at most 1 mg/litre.

The amounts with measurable cognitive deficits were less that the amounts added to drinking water in the US in several of the Chinese regions. It's in the study's data.

The study Developmental Fluoride Neurotoxicity: A Systematic Review and Meta-Analysis [1] (discussed in your link above) has data on drinking water in China.

It includes quotes relavant to the USofA:

    Such circumstances are difficult to find in many industrialized countries, because fluoride concentrations in community water are usually no higher than 1 mg/L, even when fluoride is added to water supplies as a public health measure to reduce tooth decay.

and

    In response to the recommendation of the NRC (2006), the U.S. Department of Health and Human Services (DHHS) and the U.S. EPA recently announced that DHHS is proposing to change the recommended level of fluoride in drinking water to 0.7 mg/L from the currently recommended range of 0.7–1.2 mg/L, and the U.S. EPA is reviewing the maximum amount of fluoride allowed in drinking water, which currently is set at 4.0 mg/L

Note that the U.S. EPA is reviewing the maximum amount of fluoride allowed in drinking water concerns levels naturally occuring and is not a recommendation to add fluoride to US drinking water in excess of 1 mg/litre.

I am unable to find data in that report that supports your assertion.

If you have data you wish to draw eyes to then please quote the numbers and link to the source.

[1] https://ehp.niehs.nih.gov/doi/10.1289/ehp.1104912

The problem is that it's an EPA recommended dosage, and not regulated nationwide, leading to a large variance in levels. "The fact that fluoridation of water is not regulated nationwide leads to a challenge for individuals interested in generating meaningful data for nationwide databases." [1] In the short list of measurements in the quoted paper, it ranged from almost nothing to 1.5 mg/L, and that's a very small sample. Borden County in Texas has levels above 5.5 mg/L in some areas [2]

[1] https://www.ars.usda.gov/ARSUserFiles/80400525/Articles/jfca...

[2] https://www.beg.utexas.edu/files/content/beg/research/TCEQ_s...

You still have not supported the claim made above that:

> The amounts with measurable cognitive deficits were less that the amounts added to drinking water in the US ...

Your first link ( [1] ) cites a source in Springfield as the maximal value seen (in that report) of 1.5 mg / litre (with no mention of whether that's due to added fluoride or a result of natural fluoride in the groundwater).

Your second link ( [2] ) is about an untreated groundwater source that serves 150 people with:

    Fluoride has been detected between 4 milligrams per liter (mg/L) and 5.57 mg/L from July 2002 to March 2007, which exceeds the maximum contaminant level (MCL) of 4 mg/L as well as the Secondary MCL of 2 mg/L set by the USEPA.

and is titled as a DRAFT FEASIBILITY REPORT looking at the costs of treatment with (for example) :

    Centralized treatment alternatives for arsenic and fluoride removal have been developed and were considered for this report; ...

To summarise; you have claimed but not demonstrated that intentional treatment in the USofA has added fluoride to reach levels that (are assumed | correlated ) caused IQ losses of less than half a point in China.

Your link clearly do not support this, Borden County is untreated and the intent is to look at reducing the high fluoride levels.

You should re-read the study I linked:

"The average loss in IQ was reported as a standardized weighted mean difference of 0.45, which would be approximately equivalent to seven IQ points for commonly used IQ scores with a standard deviation of 15."

Seven points IQ difference.

Also, if you bother to look at the data in the linked paper, many of the regions with measurable deficits were in the 0.5 to 2 mg/L range, well within typical treatment levels in the US.

Fair point re: IQ - I misread that.

> Also, if you bother to look at the data in the linked paper, ...

Excuse me? Mind the shade please.

> many of the regions with measurable deficits were in the 0.5 to 2 mg/L range

Exactly how many of the 27 studies listed actually had "high" fluoride values in that range?

If you bother to look at the data you might concede it's not "many" by a long shot.

More to the point, in those few studies with low fluoride levels how much was IQ correlated to fall?

The meta study findings were:

    Findings from our meta-analyses of 27 studies published over 22 years suggest an inverse association between high fluoride exposure and children’s intelligence. Children who lived in areas with high fluoride exposure had lower IQ scores than those who lived in low-exposure or control areas.

Note Well: "than those who lived in low-exposure or control areas."

It's a meta study.

It looked at studies with low levels of fluoride AND at studies with high levels of fluoride.

It determined that high levels of fluorine are not good (and that many of the studies had other issues such as lead, arsenic, iodine that had to be dealt with).

I’m not implying they’re in the same class, I’m saying that the level used is implicitly important in saying whether or not something is toxic. To me it’s not a good faith argument to assume otherwise.

You’re right I was wrong about enrichment [1] - I didn’t know that. It is wide spread, however.

The study you cited seemed to be from areas of naturally occurring high levels. So I guess I should further qualify my statement - I am to mean that it’s non-toxic at the levels used in municipal water and in toothpaste. I thought you were saying there were studies suggesting otherwise at the levels used, which the CDC disagrees with [2]. I’m now rereading your comment where you talk about the levels used so you did address that. Apologies for not better latching onto that. But it did make it sound like these levels in use were potentially toxic, which has been very widely studied across many countries over decades with increasing life expectancy and dental improvements, so it would be very unexpected if so.

It seems that there isn’t a federal requirement for fluoride in municipal water - perhaps there are areas that don’t.

[1] https://www.fda.gov/media/94563/download

[2] https://www.cdc.gov/fluoridation/faqs/community-water-fluori...

To claim that dose is the only factor involved is bad faith, or at least overly simplistic. For example, radiation and lead are cumulative. There is no minimum safe dose. Can you say definitively that there is no damage or cumulative effect from regular small dosages of fluoride?

Did you look at the study? The naturally occurring levels are below levels added to water in the US in many of the regions studied.

In any case you should be able to see that I'm not coming at this from some conspiracy nutjob angle but from sourced studies and reasonable thought processes.

My point is not that you are wrong. It's that, even if you are right, it's not some obvious open and shut case.

I was prescribed a high fluoride mouthwash, after a tooth implant, told not to rinse.It seems there are high fluoride toothpaste that is a bit expensive.

The various soaps that toothpaste is made of are not so great to leave on your mouth. If it can cause canker sores and various skin conditions in some people.

Instead just get a fluoride rinse, they're not expensive and considerably better for you than soap.

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