Brush your teeth – postpone Alzheimer's | Hacker News Reader

Brush your teeth – postpone Alzheimer's

eurekalert.org

118 pointsconse_lad76 comments

P. gingivalis has been shown that it can migrate from the mouth to the brain. It is also found in the brains of Alzheimer's sufferers. But we don't know yet if it is THE cause of Alzheimer's. Which is to say "more research is needed to prove a cause and effect link."

This is still fresh science, the ink is still wet. It might ultimately prove that the cause of Alzheimer's is P. gingivalis (which is Nobel Prize levels of incredible). However, this single 2018 study is far from the body of evidence needed to make a claim on causal link.

That being said: Please brush and floss. There's no downside. Even if it is unlinked to Alzheimer's you've gained something and lost nothing. You'll thank yourself in the long run either way.

PS - I'm not even calling the science here bad (it is not). I am simply saying, this is the start of a marathon and the article is treating it like the end. Ten years ago similar articles on prion-based infections causing Alzheimer's was the hotness, until it wasn't.

>Please brush and floss. There's no downside.

I wouldn't go as far as to say there's NO downside. Of course this makes me sound like a kook, but in the interest of full transparency: If you are using fluoridated toothpaste there are side effects of the fluoride, not to mention the other synthetic chemicals in there like sulfates that mess with your gut - and Oral-B Glide floss is made with teflon-like substances (PFAS) that accumulate in your body and cause problems.

But then again brushing with fluoridated toothpaste is one of the few dental interventions with good evidence supporting it's effectiveness (unlike flossing for instance).

I find it hard to believe this sudden flurry of doubt about flossing, just based on my own experience. I have quite packed together teeth and find flossing very fiddly, so am very inconsistent with it.

When I don't floss, after 3 or 4 months, my gums start to puff up and bleed when brushed. When I do floss at least once a week, they don't.

It was especially obvious when I smoked, a few months after visiting the dentist/hygienist I would get bleeding from my gums, at times quite worrying amounts and one of the many reasons I gave up. However, after a few nights of flossing, it would always reduce significantly.

Yes, but that is all anecdotes. Nobody with any intelligence seriously believes flossing is useless, but we don't have science to prove it, and until we have science there is room for doubt. If you don't know any science it is reasonable to argue that a heavy object falls faster than a light one, but once you do some science it isn't reasonable. (it is also reasonable to argue the other way, but most people would laugh at your argument until science proves them wrong at which point they should change their stance)

Yes it was an anecdote, but perhaps I wasn't clear, my point is that almost anyone whose gums bleed can easily test the benefits of flossing.

A much better analogy would be that people are starting to claim that farts might not smell as there's no scientific studies that conclusively say so.

As dentists point out rather regularly since that meta-study came out, they can clearly tell who flosses and who doesn't. Puffy, bleeding gums? You don't floss.

You didn't have to labour the point about science quite so rudely, I am fully aware of the philosophy of science, thanks.

Perhaps puffy, bleeding gums are perfectly healthy, but that seems unlikely as they hurt and are unsightly. On the upside, we know an easy fix for them, flossing. Do you honestly think that everyone here, or in any dentist's surgery, is going to laugh at me for claiming that?

My anecdote: I floss very very rarely and still my gum never bleeds. So it might be helpful for you, but not for me (at least not for the preventing bleeding).

I don't think I follow. I believe we have the science to prove that having food stuck between your teeth is worse than not having food stuck between your teeth.

Parts of the puzzle are not the whole thing.

We have science that aluminium in the brain correlated to alzheimers, and aluminium cookware causes high level of aluminium in the brain - but further science can't find a connection with alzheimers and cookware. (Note, the above is the state of science as of 20 years ago, things may have changed)

>Nobody with any intelligence seriously believes flossing is useless

Incorrect, I've seen articles lately saying that flossing is useless because "there's no evidence that it's helpful". Seriously. I've even read that some dentists don't recommend it now.

It's pretty mind-boggling to me, but I have no reason to doubt mainstream journalism that makes these claims. Personally, I use an electric toothbrush, but that simply cannot get all the bits of food out from between my teeth, the way flossing does. How anyone can think leaving bits of food between your teeth all night is a good idea, I have no idea.

"There's no good evidence that flossing is effective for preventing dental carries and periodontal disease vs brushing alone" is not the same as "flossing is not effective for preventing dental carries and periodontal disease vs brushing alone." Just because evidence for something doesn't exist or is weak doesn't mean it doesn't work, it just means we haven't done the high quality randomized studies to prove it works. And I'm not sure we'll ever have that, since these sorts of studies are expensive and there's ethical issues with asking a control group to stop flossing for years.

When done properly flossing is a very low risk intervention, is cheap, has a plausible mechanism of action, has anecdotal evidence for effectiveness, and makes you feel nice and clean afterwards. So you probably should still floss, even if there is no high quality evidence of effectiveness.

There are whole countries where flossing is not a thing. Fluoridated water protects your teeth. The rest may be just culture.

Fluoride protects teeth, not gums!

Healthy teeth project gums, or rather, unhealthy teeth lead to gum problems in the long run.

... and food stuck between teeth leads to gum problems in the short run!

Almost all cultures have some mechanism of cleaning larger food particles between teeth, particularly back teeth. But, more to the point -- absence of evidence is not evidence of absence:

https://www.health.harvard.edu/blog/tossing-flossing-2016081...

Ultimately, absence of evidence when we have actual trials testing it is some evidence of absence.

> When I don't floss, after 3 or 4 months, my gums start to puff up and bleed when brushed. When I do floss at least once a week, they don't.

That's effectively the very beginning of "gum disease"; your brushing of your teeth probably keeps it in check otherwise, but if you didn't brush or floss - imagine where that could lead to.

Smoking only makes the problems worse (IIRC, it makes the gums more sensitive to abrasion and tooth decay products).

It's ultimately best to brush and floss regularly, particularly before going to bed, or directly after eating. I'd say if you had to do one or the other, before bed and in the morning regularly would be best.

Something to keep in mind also is how you floss - you want the floss to go between your teeth, but don't let it "saw" into (and injure) your gums - think of it more like a toothpick.

On top of all this, go see your dentist regularly if you can afford it. Every 6 months is fine. You can get x-rays and other diagnostics (there's one for oral cancer, among other things - talk to your dentist) that can help with your overall health. I honestly believe (anecdote) that going to your dentist regularly can be more beneficial for your overall health than going to the doctor.

Though, on that last bit, I honestly don't understand why here in America they leave it up to the patient to schedule regular doctor visits. I even asked my doctor's office staff if they could re-schedule me 6 months or a year later, and they wouldn't do it ahead of time, just "call us in a year" - which of course I never did. I suck at such follow-ups, but I've gone regularly to the dentist every 6 months for the past 25+ years - because they always schedule the next 6-month follow-up for me before I leave the office.

I don't understand why it's not done as a matter of course by regular family practice doctors (though they seem to do this - I think - for children; but at some point you "age out" - or more often, leave home out from under your parent's care).

For sure, as always that which seems obvious may not be the case. On the face of it though, awaiting a definitive result as to the benefits or not of flossing and neglecting to remove that gooey matrix of dextrans on and around your teeth which certainly provides a happy hunting ground for a diverse collection of bugs, is possibly not the best strategy.

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

You shouldn't be swallowing your toothpaste or your floss.

If you swallow your floss, you would get to live the life as a dog owner with worms except you are the dog and the owner.

There's always a downside: the time lost. Over a year we loose 10+ hours on that.

You would spend much more than 10 hours on dentists appointments if you don't do this. Brushing and flossing properly cannot be stated as a loss of anything - time, money, health, whatever, no matter how you try to frame it. Don't delude yourself and others.

Additionally, you may not notice it but it you don’t floss you are likely to have bad breath due to the food trapped between your teeth (it depends on the gaps between your teeth but any food that sits in your mouth will eventually smell like shit). Outside of the other benefits of flossing, knowing that my breath smells better and not worrying about it is worth the 5-10 minute effort once a day.

If it's 10 minutes, it goes into ~60 hours/year territory, which is about how much time you get off for a week long vacation.

Hmm, I think I’m missing the point you’re trying to make. That those 10 minutes every day will add up to the week long vacation if you skip flossing?

Basically, yes.

10 hours out of 8,760 or 5,840 waking hours.

> Ten years ago similar articles on prion-based infections causing Alzheimer's was the hotness, until it wasn't.

I think it was not so long ago that I saw an article linking herpes viruses to Alzheimer's (which sounded much more plausible than an oral bacterium). Something must be causing those amyloid deposits...

I don't know where I picked up the idea, but I've long thought that it makes a kind of sense that oral plaque and gum disease would be linked to heart and brain diseases.

>I don't know where I picked up the idea

It is possible that you might have been pre-conditioned to think that way by the colossal dental industry; which has put out a fair amount of graphic imagery ranging from the saccharine to alarming, surrounding various aspects of oral hygiene and endorsing a variety of bacteria destroying toothpastes & mouth-washes to plaque-hunting rotating brushes in multitude of configurations etc., which compounded by this topic appearing with some regularity on HN might be reinforcing some of your preconceived notions.

Regardless, maintaining basic oral hygiene should be de rigueur, despite how feasible or tenuous the link(s) to other conditions might be.

A recent study I've seen suggests that all three might have a causal role to play. Going from memory, the research suggests that amyloid plaque is part of an immune response to pathogenic infections in the brain. So herpes or P. gingivalis infections might trigger the build up of the plaque. The other causal factor is that certain forms of these plaques have prion-like properties, in that they induce a malfolding that has increased toxicity.

Wouldn't it be incredible if multiple independent lines of inquiry converged into a single unified explanatory framework?

It could well be that more or less any infection in the wrong place could cause it. It doesn't have to be a specific bacteria.

This is tangential to your post but flossing is one in a series of things (including: washing and refrigerating eggs, vaccinating for chicken pox, circumcision) that Americans insist are absolutely critical for health but that are virtually nonexistent in Europe (or at least here in the Netherlands)

This is going to sound like a shill but I have to recommend the new Gum Detoxify toothpaste from Crest and thought I'd share it with other Hacker News readers. It has stannous fluoride and that is supposed to work better and actually kill bacteria around your gums. The reviews for it seemed crazy positive so I thought I would try it and it has been a product that actually does what it says.

I have to say, I wake up without morning breath pretty much now, which is insane. And I have been feeling better...

Here is a paper comparing stannous fluoride with the traditional type. https://www.ncbi.nlm.nih.gov/pubmed/30797255 "Antimicrobial effects of a stannous fluoride toothpaste in distinct oral microenvironments."

I was using a brand called Paradontax, which is a stannous fluoride, but it was causing noticeable yellowing which is a common downside to using stannous fluoride. I switched over to the Crest Detoxify Kit instead, and it seems to work just as well, but the whitener it includes not only prevents yellowing, it's clearing away the yellowing I already had, so I'm super happy with it.

I've always been bad with my teeth, but in the last few months month I got serious after being chastised by my hygienist, so I bought a Waterpik, those toothpastes, and a mouthwash for dry mouth, and my mouth has never felt better and cleaner.

related concept Probiotics for your mouth https://probiorahealth.com/?msclkid=3bfa04734b5c1067a58a5885...

I would like to see more research in this area. It seems that the main school of thought is to focus removing as much bacteria from the mouth as possible, but I'm interested in the possibility of outcompeting the undesireable bacteria with probiotics.

By probiotics you mean introducing carefully selected bacterial strains into the mouth?

See, the problem with that is that P. gingivitis is extremely competitive and prolific. This is why it's so common, and why it is so hard to outcompete.

Stannous flouride (ie tin) in toothpaste is nothing new. Nice that Crest has figured out some shiny new marketing, but ironically the original bog standard original Crest in 1954 was tin fluoride until they moved over to monoflurophosphate for cost reasons.

The original stannous fluoride formulas stained your teeth, it's not just marketing.

Stannous fluoride isn't new, it was the original fluoride compound in toothpaste until sodium fluoride got more popular.

There's also nano-hydroxyapatite (n-Ha), a bioactive form of calcium apatite that has been found to stick to dentine and help remineralize your teeth [1] [2].

It's popular in Japan, where it's even added to things like sports drinks. It's not easy to get in the West yet. The only toothpaste I know with n-Ha is Boka [3], and there's a more expensive Japanese one on Amazon called Apagard Premio [4].

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4252862/

[2] https://www.sciencedirect.com/science/article/pii/S030057121...

[3] https://www.boka.com/products/ela-mint-toothpaste

[4] https://www.amazon.com/Apagard-Premio-toothpaste-nanohydroxy...

> It's not easy to get in the West yet.

IIRC - it used to be "easy" - then it was pulled from the market:

https://arstechnica.com/civis/viewtopic.php?f=23&t=1372067

Conspiracy theories abound of course...

You can get Dr. Collins BioMin Toothpaste in the US now and it's basically the same thing.

The Apagard Premio stuff works. After my dentist saw my results he started importing it to sell out of his own practice.

I shared this with a biostatistician friend and he replied:

There has been epidemiologic evidence of associations between periodontal disease and several diseases/outcomes, including heart attacks, strokes and (in pregnant women) premature and/or low birthweight babies. Clinical trials of treatments for periodontal disease have thus far not shown any benefit in terms of these outcomes. For example:

https://www.ncbi.nlm.nih.gov/pubmed/19701034

What is his idea of the true instrumental variable? Immune system? Different genetics in collagen or lipids?

The Research Article: https://advances.sciencemag.org/content/5/1/eaau3333

Zimbabwean here but live in Canada now. There are numerous older people back in Zimbabwe who probably haven't seen a toothbrush aside from an ad in a newspaper (they are 70+ years of age). No Alzheimer's to speak of its possible this is an anecdote but I don't hear of its prevalence there or other non-north--american countries. But then again those countries don't have as big of a media footprint and research. I still think it's something westerners do (or do not do!) that causes its prevalence here.

At least in the mid-2000s, Zimbabwe had the lowest life expectancy in the world, according to the WHO. There are differences in distribution, particularly skewed due to infant and childhood mortality rates, but I'd still expect to see significantly lower rates of late-onset diseases in Zimbabwe. Even looking at the percentage of 70+ year-olds with a given disease, I'd expect significant survivor bias; if people don't live long once they get a given disease, the percentage of the population with that disease is low. You need to be much healthier in Zimbabwe in order to reach old age.

Differences in access to diagnosis can also skew statistics. We don't actually ever know prevalence of a given disease, only diagnosis rates (and perhaps gross estimates of underdiagnosis and false positive diagnostic rates).

Given the factors above, looking at any late-onset disease, I'd expect that the percentage of people living long enough to be diagnosed is much lower in Zimbabwe. Even when just looking at people over the age of 70, I'd expect the percentage living with any given disease that significantly affects life expectancy to be much lower in Zimbabwe.

Having a good healthcare system deceptively skews lots of health-related statistics.

As far as factors related to the article, Western diet is probably much higher in sugar and meat than an average Zimbabwean diet over the past 70 years. I have several dentist friends here in Hong Kong who mention patients being skeptical about modern dental practices because their grandparents never had problems, forgetting that their grandparents had diets much higher in plants and much lower in sugar.

A lot of brain diseases are proving difficult to treat due to the “blood-brain barrier”[1]. Could this bacteria be genetically modified to achieve this purpose? If so, the bacteria, when absorbed through the gums could be used benevolently to provide treatment for all sorts of brain diseases.

[1]: https://en.wikipedia.org/wiki/Blood–brain_barrier

Yes, because giving people meningitis or worse is an excellent way of treating them. To death.

There are many ways to pass BBB but few of them are actually safe. This one is not.

I wish there was some way to compare / visualize where I should be putting my effort on this stuff.

Surely I should do better taking care of my gums (flossing...:|), but I also need to improve my diet and exercise, among other things.

I'd hate to find out that the things in my life that I do manage to fix turn out to be more difficult and less effectual than other options...

Twice a day of brush, floss, and rinse is the bare minimum to keep healthy teeth and gums

I bought a nice electric toothbrush and water flosser, so I feel like I get a better job done faster (Sonicare and Waterpik)

You should not rinse directly after brushing. Toothpaste has a higher concentration of fluoride than any mouthwash, if you're going to use a rinse the recommendation is to wait 30 mins after brushing, and you should never rinse with water

> you should never rinse with water

This is going to be a stupid question. What do you rinse with?

Also, if you're not supposed to rinse for a while after brushing, and you're not supposed to brush for a while after eating, and anyway eating with morning breath is gross, but so is eating with toothpaste-breath... when the hell are you supposed to eat breakfast?

You don’t. You spit it out and go about your day.

Seconded: https://www.nature.com/articles/sj.bdj.2014.1057.

Is this common advice? I would find having my mouth coated with toothpaste residue to be extremely off putting. You would also end up swallowing quite a bit, yes?

Leaving toothpaste residue (containing fluoride) on your teeth is the main thing toothpaste is for.

Fluoride changes the chemical properties of tooth enamel to make it stronger. So removing toothpaste immediately after applying it reduces the effectiveness.

If not rinsing is intolerable then rinsing with a fluorinated mouthwash, which provides less fluoride that toothpaste but is still better than nothing, would be a better choice.

It’s common advice from all the dentists and hygienists I’ve ever seen, and it’s not something that comes up in conversation among my friends here but from personal experience I wanna say all or most of my partners I’ve ever seen brush their teeth they do the same. If it helps, this is in Europe, so we (as in dentists here) may have differing guidelines as you.

From what I know, the gist is that fluoride is mineralized into enamel which strengthens it (not sure if this is the correct phrasing). Whatever the correct phrase is, it works by direct prolonged contact. Not rinsing is a way to guarantee this contact, but even if you do there’s still fluoride in your saliva to do some good.

I imagine the taste depends on your toothpaste. I use a plain one (Elmex) that doesn’t really have a taste, and the taste goes away fast enough that I don’t notice it.

As far as swallowing goes, not really. Most of it gets spat out. Besides, (some) astronauts in space just swallow it all instead of spitting cause it’s cleaner :)

https://www.quora.com/International-Space-Station-Is-it-ok-t...

Yes I know fluoride can be toxic but the amount you’d swallow (a small pea sized dab is all you need, all those pictures of the entire brush covered by toothpaste is advertisement to get you to think you need that much) is probably not going to have any effect.

It's fine to swish and spit with a small amount (~5mL) of water, making a "slurry" with the toothpaste. It may even be beneficial because the swishing would coat all of your mouth's surfaces.

https://www.berkeleywellness.com/self-care/preventive-care/a...

From what my dentist told me, while a water flosser is nice, it doesn't replace flossing. It basically does half of what normal flossing does.

Me and thousands of dollars in periodontal treatments are a living anecdotal testimony to that fact. mechanical disruption of the biofilms in the interdental space is the only known efficacious prophylaxis for gum disease that I know of. The water pik feels great but just doesn't do the job.

There was a thread on reddit asking dentists questions and what stood out to me was unanimous agreement in multiple separate convos of dentist redditors that electric toothbrushes work better than manual. The theme every time was: Use electric. Use very light pressure (don't even open your mouth too wide because your cheeks add pressure). Spend a good amount of time on each tooth --to the point they recommend brushes with built-in timers to keep you on the clock.

As for flossing: All I know is that before I started flossing, I was accumulating measurable gum damage. After I started, it healed. Now when I slack off, I get sore spots. When I start again, they heal. And, when I'm flossing I find it incredible how much gunk I pull out of my gums even right after a through brushing. It's gross. But, far more gross would be just leaving it there to rot.

Serioulsy, brush your teeth to avoid tooth decay and dental problems, as fixing those will be expensive, painful and still lead to substandard replacements.

It there is a single personal care thing I wish I listened more to my parents and common sense, that's it.

Diet and exercise are important as well but, compared to those, the amount of effort, willpower and discipline associated to keeping your teeth clean is risible.

I've always wondered what is the order of importance when it comes to oral hygiene. Brush, paste, duration, technique. Further which is more important, brushing, flossing or a good mouthwash? Is there anything that survives a chlorhexidine rinse?

For what it's worth, my dentist told me he didn't care if his patients brushed their teeth or not, as long as they flossed.

My dentist always said, "brushing is for you, flossing is for me." (He meant that brushing is to remove the bad taste teeth fuzz, but flossing is what keeps my teeth and gums healthy.)

I’ve heard the saying “you only need to floss between the teeth you want to keep” in response to the question “do I really need to floss?”

A fun variation is pausing to floss halfway through brushing your teeth — foamy mouth and all. A major function of toothpaste is that it breaks up bacterial biofilm, so it provides a nice buff to the mechanical action of flossing.

> Is there anything that survives a chlorhexidine rinse?

At first I was going to ask if that was the stuff in original Listerine (if you don't recall or remember, or too young to know, Listerine used to sell a version that was a yellowish-tint, tasted like crap, and burned the s--t out of your gums and mouth; likely it was just high-proof alcohol, and the same could be done with some cheap vodka)...

Now I'm wondering if chlorhexidine is the stuff my dental hygienist gives me to rinse my mouth out with before she starts to clean my teeth - I'll have to ask.

Wow, this is the kind of article that amazes me on HN. And why I keep coming back.

How about mouthwash?

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