This can go wrong in either direction. If you brush your teeth and have milk shortly after, the fluoride binds to the calcium in milk and goes to your belly instead of staying with your teeth protecting them. On the other hand if you have orange juice or similar (acidic) and then brush your teeth, say bye to your tooth enamel.

> On the other hand if you have orange juice or similar (acidic) and then brush your teeth, say bye to your tooth enamel.

How long would you recommend to wait? Or perhaps a good rinsing of teeth before brushing would be enough?

Acid loosens the enamel, so careful with anything like good rinsing or brushing right after consuming acidic items. Just drink some water (optional light rinse) and wait around 30 minutes to brush.

* Disclaimer: I am not a dentist, you should find a good one and talk to them for real advice.

Why is there no winning in this situation?! I have never realised something as simple as brushing teeth can be so nuanced lol

It's not nuanced.

The evidence is just lacking, people are just using judgement to advise on something that we can't detect one way or another with research.

When it comes to dental care it's not even clear, based on research (Cochrane review in 2019) it flossing makes any difference let alone a clinically useful difference.

The current advice is just based on reasoning that either you brush first or wait a hour after eating due to the abrasive action of brushing.

Regarding flossing, at least in my case, it helps with my gum disease. If I don't floss for a while my gums start to bleed. Although, I use a water floss instead of a regular rope floss

Yeah, flossing is a good idea if you don't want to get gum disease. Also a good idea to learn to floss correctly, not just a quick "in and out". (also good idea so you don't get cavities on the edges of your teeth.) https://www.youtube.com/watch?v=WviE5aa5Ha0 (how to floss)

It's not clear because it IS nuanced, and it doesn't have the same effect on everyone equally. Two people using the exact same dental routine can have vastly different results from it.

I'll take the Cochrane opinion that evidence is lacking due to low quality small sample short follow up studies in those with poor dental hygiene.

Over the random internet randos views.

But thanks none the less!

I’m glad ifnflossing helps fights cavity but the main reason I do it is because it’s so gross not to. When you don’t floss you basically accept to keep bits of rotten food between your teeth for days. If you’re unconvinced, don’t floss for a week and then do, see what comes out. And don’t smell it. I warned you.

People's teeth (and brushing technique/effectiveness) are way too varied to make such a general statement. I flossed for the first time at some point in my 20s, did religiously for a year or so thereafter, and still do occasionally - but at no point was it like 'how on Earth have I not been doing this' or loads of gunk coming out, nevermind rotten and smelly. Maybe you have just the 'right' tooth gap that it's both too tight for your brushing but not so tight that stuff doesn't get stuck.

(And for whatever it's worth, all dental check-ups since some point in my early teens at the latest have just been a quick look around and yep all good - I'm not saying this from a position (touching wood I don't eat my hat next time of course) of terrible dental health.)

> People's teeth (and brushing technique/effectiveness) are way too varied

You're absolutely correct, because I don't floss that often, but every time I do a whole meal comes out, so I'm incredibly envious of your naturally clean teeth XD

Saliva does help in preventing bacteria build up. [1]

[1] https://pubmed.ncbi.nlm.nih.gov/1961328/

A checkup shouldn't be too quick, there are things they should be checking and looking out for: https://youtu.be/sDe50j0MFBU?t=95 (Dental Office RED FLAGS)

Yeah they really hooked the public with that.

Same with hair, and bacteria on surfaces.

Completely hookwinked Jo public.

I guess a diet without those foods is the best solution

Didn’t people not brush at all in the past but still had perfect teeth?

I'm pretty sure prehistoric people did have primitive tooth care, didn't eat junk food and high-sugar diets, and still had nasty teeth.

Genes, climate, and types of local foods play a role too, but widespread adoption of agriculture made diets rich in carbs and starchy foods possible, which isn't great for dental health, and the somewhat recent trend (last 200~ years) of highly processed foods that are softer and easier to chew means there's less mechanisms to deal with tooth overcrowding. This has been observed in children from hunter gatherer societies, raised on modern diets, having worse dental hygiene than their parents.

They had two sets of teeth and they were perfect for the average life expectancy of around 35.

> Teeth-cleaning twigs have long been used throughout human history.[2] As long ago as 3000 B.C., the ancient Egyptians constructed crude toothbrushes from twigs and leaves to clean their teeth. Similarly, other cultures such as the Greeks, Romans, Arabs and Indians also cleaned their teeth with twigs. Some would fray one end of the twig so that it could penetrate between the teeth more effectively.

https://en.wikipedia.org/wiki/Tooth_brushing

IMO teeth are the worst part of the human body. Hard to take care of, will inevitably fail, not replaceable, massively painful for even minor injuries. Evolution really screwed the pooch on teeth.

Our diet is nothing like what our teeth evolved for. For example for most people, cutting down the amount of sugars (down to levels similar to our prehistoric ancestors) they consume can go a long way in protecting dental health (and general health for that matter)

Teeth are the canary in the coal mine. "The canary is the worst part of the coal mine, it can hardly handle anything!"

Somewhere evolution is saying “well I gave you four perfectly decent extra molars that you insist on ripping out, if you kept those your teeth would be mostly fine for however long your are supposed to live. Mid 50’s?”

Sharks really got the good teeth genes.

Would be fun too have re-growing teeth, probably not so fun to swallow them in those sizes so frequently.

Teeth are amazing. One of the areas where human crystal formation happens. Our modern diets are horrible for teeth.

https://m.youtube.com/watch?v=t4RgBZlKlJI

Evolution expects us to grind away about a millimeter of our teeth while we are young by eating rougher things to make way for wisdom teeth, for example.

For healthy teeth, you should be very hydrated. If your mouth isn’t watering, you might not be hydrated enough.

Haven't watched the video, but:

> One of the areas where human crystal formation happens

Especially one of the areas where you want crystals to form. Unlike in your urinary and bladders. ;)

Well, teeth perform perhaps the most difficult task of the entire body. Take entirely external substances of all kinds of textures and densities and contaminants, crush all that to tiny particles, try not to get worn down too far in the process...

Spines seem to be similar in that regard. Huge "fuckup" (bound to fail badly) in many ways, but freed hands.

Feels like engineering: It's all trade-offs.

People in the past had better teeth than us, it's the sugar these days that cause so many dental problems. If you ate like those in the past, you similarly will have good teeth.

> I have never realised something as simple as brushing teeth can be so nuanced lol

I feel like replacing "brushing teeth" with literally anything and your sentence is also correct and a good way to think. Especially the things we think are easy. There's a reason it took us thousands of years to do certain things.

Don't brush before or after breakfast. Got it! Thanks!

If you follow all health advice, you realize the proper response is to just die: it’s too complicated.

No need to worry, we are all in the process of dying, so the correct answer is just to ignore everything that isn't either: something that strikes you as incredibly obvious (don't drink poison), isn't recognized in its field of experts (high cholesterol is bad for you), isn't established knowledge, or isn't too inconvenient.

> recognized in its field of experts (high cholesterol is bad for you)

Public service announcement: this one is controversial. IMHO it's wrong, based on bad science and agendas, and harmful because it deters people from nutritious foods. I recommend everyone do their own reading to form their own opinion.

It's sad how political food and nutrition is because it causes misinformation and malnutrition.

Are you a medical doctor or otherwise considered an expert in the field of internal medicine?

Steroidogenesis starts with cholesterol. The body increases its cholesterol production in the hopes of getting more steroids.

https://upload.wikimedia.org/wikipedia/commons/thumb/1/13/St...

Medicine’s misunderstanding of cholesterol is one of those mistakes which became very profitable for the pharmaceutical industry.

My rudimentary understanding: chronic high blood sugar causes irritation of blood vessels; irritated blood vessels attempt to protect themselves by producing a protective layer (excretion?); cholesterol sticks much more readily to this‚ causing creation of plaques. So, cholesterol is "fine" if you avoid high blood sugar.

> to just die

But before brushing or after brushing??!!

I've only been brushing my teeth before bed for like 6 years at this point, and flossing once a week or so. I don't know if it's the fluoride alcohol mouth wash I use or just dumb luck, but I haven't gotten any cavities

So I think that given this rigorous scientific data, you can safely avoid brushing for the most part

It's complicated. There's definitely a genetic component to having hard teeth.

A lot of it is diet too. Not eating or drinking sugary things gives you much more room for error. Of course you still need to brush and floss, but in my experience sugar + rigorous cleaning can still leave you with cavities whereas no sugar + lax cleaning you're probably fine. No sugar + rigorous cleaning and you might never need a dentist again. It took me way too long to understand this.

fwiw, I have pretty bad teeth (~10K for crowns etc a few years ago).

And I switched to only brushing with an electric toothbrush before bed, and don't really floss and think I've only had one small cavity since then and the hygienist said my teeth looked quite good in general.

Worth noting that I have a good diet and rarely eat sugar beyond yogurt.

Razors pain you; Rivers are damp; Acids stain you; And drugs cause cramp.

Guns aren’t lawful; Nooses give; Gas smells awful; You might as well live.

I always drink coffee, which is acidic (I think) with milk, for breakfast, so I guess I should just give up on teeth?

I try to brush before eating and drinking, but on the rare occasions I end up brushing afterwards, I wait the better part of an hour so that the acids are well enough diluted to cause trouble.

Did you know that after brushing with toothpaste you're supposed to just...let the foam hang around in your mouth without rinsing it out for 30 minutes? I didn't until recently, and now that I do, I'm still not gonna walk around with toothpaste foam in my mouth.

How much foam do you end up with? I usually don't rinse out the toothpaste after, but I don't end up with a foaming mouth after. I use about a pea size amount (as recommended on the packaging) and it's not super sudsy when I'm finished. Wipe my face and done.

Not too much but it just feels disgusting to me to keep all of the food bits still suspended in the foam in my mouth.

I'm confused - what food bits? Do you have detectable food bits left over after brushing or is it an impression that there must be food still left over?

At least for me, I rinse out my mouth before I brush, so I don't expect to have detectable gunk left over. I also use a tongue scraper after, so I'm usually feeling pretty clean when I'm done.

Well both, stuff between the teeth that the brush doesn't get (I guess that's why you'd floss after brushing, but also with foam in your mouth?), and also just food microparticles that would go away when rinsing after brushing generally.

I suppose it helps to floss before brushing (as recommended) but for me personally the stray particle isn't something I've worried about. In my mind, the added benefit of retaining the fluoride longer outweighs the downsides of microparticles of food.

> I suppose it helps to floss before brushing (as recommended)

Wellp, that's something I've never heard before. Even at the dentist, when she does a cleaning, flossing comes last.

Honestly, the timing of flossing is the least important thing about it, considering most people are averse to even doing it. The payoff with flossing before brushing is that any gunk that gets brought out and left over after rinsing gets scrubbed away during brushing.

https://www.healthline.com/health/dental-and-oral-health/flo...

If you have food microparticles that would go away, then rinse them out, then wash your teeth again and keep that foam in.

I floss first, rinse, then brush. No more food bits left after I spit out the extra foam.

There's a particular prescription strength toothpaste I use when I get sensitive teeth. I keep it specifically for post-dinner brushing and it's easier to do this at that time.

Yeah, I learned about this a while ago and now I don't rinse my mouth after brushing. Which is weird initially but you get used to it.

I _do_ spit out excess toothpaste, which I understand still leaves enough toothpaste in your mouth for it to do it's thing.

I just use a flouride-based mouthwash after and call it a day. I await someone telling me how that's a bad idea and now i'm going to die.

How about mouthwash first thing in the morning to nuke the bacteria without coating your mouth in fluoride?

Dentists I've been to have said not to use mouthwash - it kills good bacteria too.

It's easy to get toothpaste without fluoride

You want the fluoride to remineralize your enamel.

but what's the point? toothpaste is mostly a fluoride delivery mechanism.

Yep. Thats why they recommended to wait about 30mins after brushing before you eat. Also at least 30 mins after brushing before eating. Ideally don't graze eat throughout the day. Highly recommend checking out the TeethTalk YouTube, she's a Dental Hygienist and covers allot of dental topics, and it's free. idk where your from, but dentists here are crazy expensive. https://www.youtube.com/@TeethTalk

Funny, all my dentists always urged me to do morning brush after breakfast. It seemed to correlate to "brush after each meal" thing.

Mine says half an hour before or after, which I like because it makes sense. He also suggests after lunch, and of course in the evening, which obviously comes after breakfast - so it's kind of annoying (you know, to the kind of person spending time on HN) to leave it at 'brush before breakfast not after' or vice versa...

Since apparently you can get two conflicting “educated” opinions, chances are it doesn’t matter anyway.

I think it's both the bacteria thing – getting rid of them before they can start metablizing your food into stuff to harm your enamel – and the idea that directly following food intake, your mouth pH level will be out of homeostasis and enamel may be easier to erode at "non-native" pHs and one shouldn't brush directly after. I'm not sure where I got that from though.

Yup, both removing them first and then layering a bit of protection (fluoride).

If I brush before eating the food tastes bad

Same, I naturally avoid anything acidic after brushing, things like orange juice just taste horrible after brushing.

This is due to the foaming agents used in most toothpastes. The biggest culprit is sodium lauryl (ether) sulphate (SLES/ SLS). These foaming agents are surfactants and they bind to certain taste receptors in your mouth, thus altering your taste perception. You can avoid this entirely by switching your toothpaste to something that uses no foaming agents or those of the non-surfactant type.

Some people are also allergic to them. I was getting canker sores in my mouth for years without understand why.

Then my cousin discovered he’s allergic to SLS. I quit toothpaste with SLS and I never get them anymore. It’s rare but you never know who else struggles with it and doesn’t know.

Do you know any US toothpaste without sulphates that is not a scam like 99% of the brands, that typically charge 300% more for ADs like (whitening bla bla..)

IIRC the reason for this is that antibodies are actually in your saliva, which moves around your mouth much less while you're sleeping. Thus, bacteria have a more favorable environment at night.

That would explain morning breath.

I found that rinsing my mouth after brushing and before going to bed with baking soda dissolved in water makes a notable difference there.

And don’t use Listerine etc, their alcohol content is way too high and leads to cancer over time apparently.

Seems to me like one should just not eat a sugary breakfast?

Acidity is more the issue aiui, I don't really eat breakfast typically but my dentist's example was coffee (to which I don't add sugar) - drink water after coffee, and don't brush for half an hour after.

Yeah if you feel like making your breakfast taste like garbage as the toothpaste blocks sweetness receptors.

You can get toothpaste without sodium lauryl sulfate.

TIL, that would be interesting to try then. I hope they're not overly expensive?

I think it's often like 2-3x the price of cheaper brands, but that doesn't really add up to much ongoing cost.

Trader Joe's peppermint anticavity toothpaste. Was a bit odd at first as it has baking soda in it, but after a tube or two I think regular toothpaste is really the odd tasting one now. Cheapish.

Yes. Best talk on teeth hygiene and anatomy (in that order) I’ve heard - https://podcasts.apple.com/us/podcast/patricia-corby-d-d-s-i...

brush before and have a good wash after as well

I couldn't imagine consuming anything before brushing my teeth, but this is coming from a retainer wearer so I think that might have something to do with it.

I've heard that brushing right after eating is really bad for your teeth because just after you eat, the bacteria in your mouth start producing acid that, for lack of a better word, loosens the surface enamel in your teeth, and brushing in that state discards that enamel instead of letting it resettle after the acid washes away.

The solubility of enamel is insanely low so the effect should be minor at most, but still.

The bacteria is one thing, but acidic foods are another. Brushing after citrus will destroy your teeth over time. Not sure about coffee.