Why Are Human Teeth So Messed Up? | Hacker News Reader

Why Are Human Teeth So Messed Up?

aeon.co

294 pointsdrchip159 comments

It always struck me as funny that if you want to get into Medicine you can either do the normal MD course that covers 95% of the body (obviously, you may be able to specialize much later on) OR you can do the other 5% as a Dentist (and again, you may chose to specialize later).

Teeth suck, I'm hanging out for "I can't believe they're not teeth" implants so I can stop worrying about the damn things.

The sucking pressure is actually created by the lungs (or diaphragm) not the teeth. It's not clear which specialty is taught that.

It's primarily the tongue.

Certainly in those cases where teeth are not advised.

I have an "I can't believe it's not a tooth" implant, after I lost a front tooth when I crashed a tiny motorcycle.

They drilled a hole in my jaw, beefed it up with a "cadaver bone" from a pig, threaded a titanium bolt into the hole, and then threaded a tooth-lookalike into the titanium bolt.

The installation is a bit... industrial, but you'd never know it wasn't a real tooth. It cost £3,000 though.

There's also BioImplant (Austrian based), which uses Zirconium and has a good rep:

http://www.bioimplant.at

Titanium screws can have issues, where's the Zirconium-moulded-to-the-original-tooth-shape approach seems better.

Next time take a vacation in one of the balkan countries, get an implant, and maybe even save some money.

What kind of deductible is that in $?

Neato, from a 'user' perspective how is it? Does it feel or work any different to a usual tooth?

Just like a normal tooth, except the surrounding part of my mouth is a little "bulkier" at the back where the cadaver bone was placed.

No complaints at all.

Interesting! Thanks for the info though, always been something I found quite interesting

Teeth are also more intricate and "fiddly". Superficially arms legs fingers and toes are the same thing. Organic leverages. Their makeup due to evolution is advanced, but very straight to the point. They are also big. Teeth are small micro structures.

The major organs are all over the place. The heart and lungs oh so important, yet they be glorified pressure pumps nonetheless. The liver on the other hand, throw any shit into there and it magically outputs clear lifeforce for the body. Very interesting.

This is from a surgical point of view, as I view dentists also as surgeons in the mechanical regard. You have individual branches when you get into genetics/biology off each individual part, which is a whole different level off complexity.

The brain has neurologists, neuroscientist, psychiatrists and psychologists. Also very complex.

I think another reason might simply be the natural tendency to first tackle which lies in front. While genetics and such are interesting, people need direct help with broken limbs and failing organs, creating a pushing need for people requiring such skillsets. Teeth score the highest in this as well. If u break an arm it's w/e but teeth issues are often felt instantly and persist continuously if not dealt with.

Having an implant takes a lot more maintenance than regular teeth and no one really knows the long-long term results (modern implants haven't been around long enough).

While an implant may offer a much better quality of life vs having a severely poor tooth (or none at all), don't be fooled into thinking you just get one and then you're set for life.

They are considered an excellent option in a lot of cases, but you should never sacrifice your real teeth. You trade in worrying about cavities (real teeth) to worrying about a bunch of implant specific problems. All of which are waaaaaay scarier than cavities.

Cavities are not the problem. Abscesses and infections are the problem.

An untreated abscess can have very severe consequences, up to and including death from sepsis.

Implants need to be kept clean, and the risk of infection is slightly higher than with normal teeth. But they rarely become a bacterial reservoir - which isn't a rare consequence for the roots of normal teeth when they're not kept as least as clean.

That's a problem with implants now, I'm hanging out for something that doesn't have those problems.

That's where it gets tricky.

Let's say something substantially better comes out 5 years from now.

Do you really want to be a guinea pig for that?

You may end up waiting 10 or 15 years after the new thing comes out just to make sure it's properly field tested and successful in a majority of people. Plus, you still don't know how long it will really last because there's no real world data.

Then there's the whole skill level of the surgeon placing the implant.

Some dentists take 2 day seminars to learn how to place implants, and are able to start doing them on real people afterwards. Do you really want that guy to do the job for you?

Because it's going to take 5+ years before anyone builds up enough experience to be even be in a spot to say "I'm really comfortable placing these things because I've seen it all".

I was not warned about any implant specific problems during my implant last month, nor have I experienced any in the 20 years since my first implant. I was told they date back to the 60s. There is no extra maintenance of any kind. It is, in my case, a 100% replacement for the real tooth.

The anchor does, I think, prevent you from getting braces later on if you should need them.

It's really only an accident of history. This Atlantic piece goes into it: https://www.theatlantic.com/health/archive/2017/03/why-denti...

Semi-related: When I was in the canyons of New Mexico learning about various tribes and their lifestyles, I learned that many died from tooth-related infections. This is because the mortars they used were made from softer stone that crumbled in the grinding process (when they grind maize). These tiny pieces of stone essentially ground down their teeth.

If I remember correctly, because of this their average lifespan was just over 30 yrs.

Most people using stone grinding wheels throughout history has the same issue, from the beginning of farming up until a couple hundred years ago in Europe say. Archeologists use the amount of wear on a skeletons teeth to determine their age quite accurately.

This is also part of why white bread was historically considered healthier - removing the wheat germ and bran kind of faked the look of stone-grain-free bread.

Would you happen to have a reference on that?

A quick Google Books search found,

  Tosefta Berachot: Translated Into English with a Commentary

  https://books.google.com/books?id=ronqNAPipaEC&pg=PA189

Ah, an even better reference, from 1906, which also mentions teeth.

  Lieut.-Colonel Allan Cunningham desired to contrast the
  highly scientific process of grinding in use at the present
  day in all civilised counties with the unscientific process
  of grinding on a very large scale amongst the huge
  population of North-West India, which was essentially a
  wheat-eating population. The wheat was ground there in hand
  stone mills; the grinding was coarse, and separation of the
  bran very imperfect, there being a good deal of bran in the
  so-called flour. The bread was unleavened bread, whereas the
  bread eaten in this country was leavened bread, which made
  in immense difference in its effect on the constitution. The
  native flour was simply kneaded with water, and quickly
  heated over a griddle. With the addition of a little milk,
  butter, and salt, that was the staple food of the
  population.  The effect of the diet was that the population
  were inferior on the whole in physique to Europeans, but it
  must remembered that they did not have a varied diet. The
  people had extremely beautiful teeth which they carefully
  cleaned. One very curious effect, which was always ascribed
  to the eating of the native ground what, was that the
  natives were extraordinarily subject to stone, even little
  children frequently having bigs stones in the bladder.

  Journal of the Society of Arts, December 21, 1906.

  https://books.google.com/books?id=DfpFAQAAMAAJ&pg=PA127

Thank you!

My ancestors threw off the archaelogists by only dining on the soft heated innards of dead animals. Their teeth were a pointed exercise in falsification.

The same problem was with pharaohs. The stone tools that were used to make bread consisted mainly of sand which grinded ancient egyptians' teeth. National Geographic magazine had some x-rays that indicated that they were in pain.

Just a reminder that low life expectancy is largely the product of high infant mortality rates bringing down the average. If you were to survive to adulthood in the ancient world you would probably not die at 30, but something more like 60.

Sometimes I hate statistics.

Average lifespan isn't a particularly useful measurement for those who have survived infancy due to extremely high infant mortality rates in the past.

Individual life expectancy changes each year of your life based on how many years you have already survived. (See: actuarial life tables)

The standard approach to orthodontics is to extract teeth to make room and then move the remaining teeth into place. There is an alternative approach which involves enlarging the jaw, either through expanders, surgery or a combination of both.

Unfortunately this is an area where the patient or parent often has to make the decision because specialists only know about what they do. As a related example, I asked a dentist and an orthodontist what was more suitable for me, Invisalign or braces. They could each tell me about the time and likely result of their own specialty, but refused to offer any opinion on what was better for me and my situation.

Somewhat related, there was an interesting article about the wildly different advice given to someone who visited 50 different dentists [1].

Bottom line is seek out multiple opinions and don't expect someone else to guide you on the bigger picture.

[1] https://www.dentistat.com/ReaderDigestArticle.pdf

There's a larger truth hidden in here: experts disagree. It was one of the things that took me by surprise when building Machine Learning systems, but it makes sense if you think about it. For all but the most trivial matters, it's the job of the expert to exercise personal judgement. It's why they're experts, not because they have a solid understanding of the "knowns", but because they have developed methods and intuitions about the "unknowns". Ask 10 different experts a complex question in their field of interest, and you'll likely get widely varying answers. My guess is that it also played a role in the early expert systems AI bust (AI winter). There are interesting papers published about this as well, e.g. http://www.sciencedirect.com/science/article/pii/S0951832007... the money shot is in this chart http://imgur.com/a/shaii but you'll see similar distributions everywhere where expert judgement is warranted.

The issue with the medical profession seems to be when you ask them about something not in their specialty.

Most doctors I've spoken to without a personal relationship refuse to comment and instead refer to a specialist.

... Which forces the patient to make his or her own choice, even though they most information they have is a summary from hurried medical professionals.

I understand why they do it, but it's a suboptimal result compared to their weighing the relative merits with their expert knowledge in at least one and offering advice.

There is a corollary prediction: AIs will disagree.

Too many people imagine AIs are somehow "perfectly rational" and therefore will never disagree, they'll just tap into a unified decision making engine and automatically integrate all of their knowledge.

In order to integrate knowledge you need more knowledge. And in order to integrate that you need more still. It's turtles all the way down. If anything, AIs are at a disadvantage to humans, because we at least share a body, an emotional palette, and to some extent a cultural timeline. AIs have nothing to ground the beliefs of the other in.

If AI is to agree they need all the facts. And as we keep adding facts almost daily, there is simply no chance that the AI will have all the facts.

We like to think of logic as 1+1=2. But logic is more like A+B-C*D/E=F. Where any number of those being either completely unknown (we sometimes do not even know we are missing them), or some wide range of potential values.

You need a third model to map facts from one model into facts in another model. Doesn't really solve the problem.

Have you heard of Aumann's agreement theorem? https://en.wikipedia.org/wiki/Aumann's_agreement_theorem

Theoretically it means that two AI should be able to reach a consensus pretty quickly without needing to share a lot of information.

Unfortunately you need "honest, rational Bayesian agents with common priors" for this to work. Given that humans rarely agree with each other, it's interesting to think about where we fall short of that criteria.

I think the reason you didn't get a straight answer on the "invisalign vs. braces" is that they do such their jobs so similarly that the biggest factor is really what you want. Do you want a slower and more expensive treatment with less pain, greater dental hygiene convenience, and that less visible to people who see your teeth? Can you put up with a little pain and inconvenience, don't mind the aesthetics, and want to save money?

In some some cases (to the best of my knowledge -- I haven't had to know anything about braces in 15 years), only braces are available until the teeth are in a state where invisalign can do the rest. Clearly, you weren't one of those patients, so the rest is up to you.

The dentists don't know your financial or social situation, they don't know what kind of inconvenience you can and can't put up with. What were you really expecting them to say here?

What you say makes sense, but the people involved didn't even attempt to make me aware of the differences in the concise way you just did. And when I asked about the difference in final result, pain, and time, there was no straight answer. It was just, "This is what I do. I can't tell you about the other thing."

The author of this article works at the University of Arkansas. I used to live 20 miles from there, and when we needed to "straighten" my son's teeth, we ended up checking out an orthodontist who has been influenced by the new school of thought that is emerging in Australia and Europe on dealing with orthodontic issues.

We ended up settling on a regimen of jaw exercises combined with a device known as a "Myobrace". I was initially very, very skeptical, and was concerned about the lack of rigorous scientific studies conducted on the practice. However, the more I researched the science, the more I became open to giving it a try.

Within 6 months, my son's jaw had widened, and his teeth were mostly straight. I was honestly shocked by how effective the treatment was. It's now been almost 18 months, and the before and after photos are shocking.

He wears the appliance while sleeping, and then during the day (we use the strategy of him doing it whenever he is watching tv or playing Xbox) we have him do jaw exercises with and without the appliance in.

The focus has been on expanding his jaw, and the side effect of this is straightened teeth. Pretty fascinating stuff.

If you don't mind my asking, how old is your son? I'm guessing this procedure is limited by age, since bone development stops as you get older?

Correct! This is for children only. My son was 9 when we started the treatment.

I'm going to take this moment to rant at dentists!

Going to the doctor they get the excuse that they rarely do anything that could possibly hurt. Dentists on the other hand are practically doing minor surgery every time you visit them.

I know many of you will never have had any bad experiences at the dentist but I've had tons and what's extremely frustrating is many of them are preventable but dentists seem to have almost zero standards.

Examples:

Lukewarm water please. Many dentists just have tap water (maybe filtered) squirting into your mouth for rinsing. If that water happens to be cold gawd help you if you have a cold sensitive spot.

Similarly they have that suction hose which creates a draft. A draft that can cool sensitive teeth to the point they scream in pain.

One of the last dentists I went to connected something to my right cheek of my mount the hold it open. He'd turn around in his chair to get something behind him and yank my head off the headrest.

Another dentist I went to recently started cleaning my teeth. It felt like she was taking an ice pick and stabbing my gums. Needs to say I stopped her after about 30 seconds and left.

Went to a dentist that was supposed to specialize in painless-ness. He didn't have any kind of topical to numb you gums before injecting the anaesthetic. Not that it helps. It always burns like crazy when they inject that stuff for me. It does eventually make that part of my mouth numb though often not numb enough so when they get deep and they have to do it again.

When they hit pay dirt it feels like someone took a 6 inch white hot nail and using a hammer pounded it 4 inches deep into my head. The pain is searing. I'm not exaggerating. On a scale of 1 to 10 it's a 45 in pain.

I have lots more horror stories. And yes I brush twice a day, floss, and do other things to maintain my teeth. My teeth aren't normally painful but every visit to the dentist is hugely scary for me.

Someone PLEASE fix dentistry.

Sounds like you have some gum recession ('sensitive teeth').

Brushing vigorously can erode gums, exposing the sensitive parts of teeth. It's very important to brush gently (but thoroughly); not back and forth, rather up and down. Flossing isn't particularly good for gums, either, so best to do it sparingly.

My dentist tells me to floss specifically because it's good for the gums.

Excuse me? Flossing is critical for gum health.

You'd be surprised, but above is not the commonly accepted truth, and is debated amongst dentists. (research across countries also lends credible data to both sides in the debate).

Source: married to a dentist.

Maybe. The recommendation for flossing comes from tradition and anecdotes, not good evidence. Flossing isn't evidence based[1], though that doesn't mean it's useless and we shouldn't do it, just because something isn't evidence based doesn't mean it doesn't work.

We probably should floss because it's probably helpful, even if the evidence is weak, it has a plausible mechanism of action, it's low cost, low risk, and teeth feel good after a proper flossing.

A big issue is many people have poor flossing technique though, which is (probably) not great for gums and may actually cause problems. Flossing shouldn't hurt and you should talk to your dental hygienist about proper (recommended) technique. Also have him or her actually floss your teeth if they don't already during a cleaning (mine does) so you can get a feel of what the recommended technique feels like. Also try different types of floss. My hygienist can floss me just fine with the "normal" type floss but I can't replicate that for some reason, I need to use the "glide" type floss.

[1] https://www.washingtonpost.com/opinions/the-evidence-for-flo...

Which country/state/etc. are you in?

None of what you complain of ever happens to me here in Norway. Nor have I heard of any such scary events here in the 30+ years I've lived here. Of course I only have direct experience of a few dentists all in the same practice.

How many dentists have you gone to? Regularly changing dentists is just a bad idea.

Get a recommendation from someone you know who says they were nervous, chose a particular dentist and now would go to no one else and give that dentist a decent chance.

You need to develop a relationship with one dentist and over time you will become more comfortable with them and they with you. Everyone can be a little nervous in a new relationship. They will also have reminders on your card re your sensitive teeth etc.

You are also likely to have fewer procedures as dentists are more comfortable to keep stuff under observation with patients who they know will come back. Because you're nervous they also will be more likely to go down the advise and keep under observation route especially if your overall decay rate is low. And that crappy amalgam that looks like it needs replacing? Your long-term dentist knows it's looked like that for ten years now. All those kinds of things.

Any advice for finding a good dentist? I'm severely in need of a dentist after years upon years of neglect, mainly due to not being able to afford it, but now I'm in a position where I can at least work towards something proper. Yet, I've got no idea where to start. Thoughts?

Personal recommendations are usually how people find their dentists, I'm not sure there's any better way. Ask several colleagues and friends to talk to you in depth about their experiences. Make sure you ask if they recommended extensive expensive treatments, routinely recommending such treatments is a bad sign the dentist is doing unnecessary work for profit (which happens). Don't hesitate to call up different offices with any questions you may have. If they won't or can't answer your questions they aren't worth your time. Don't hesitate about getting a second opinion if you're not sure about their treatment plan.

Really it's about recommendations, ask lots of people who they go to and why. I'd avoid a practice that's part of a chain like the plague, they are more likely to have a high turnover of dentists, who are under pressure to produce. I'd go for a small practice with at most a few dentists all ideally partners who are there for the long haul. Definitely avoid quick jobs like combining a holiday with treatment packages. If you've left things a long time, the first task may just be to stabilise things and then you can gradually get the things you want, done. There are always options and some cost a lot more than others. It's a trade off off involving satisfaction in terms of aesthetics and function, cost and the amount of time you'll need to spend in the chair. Sorry that all sounds a bit wafflely as i write it but it's true really.

Those years of neglect are going to hurt until you get back to where you need to be. Even the best dentist will admit to that.

Have nothing but absolute rave reviews for dentistry here in Canada. They take great care of you and are always aware of how you're doing and if you're feeling the least bit of discomfort.

The only problem is it's stupid expensive; I get annoyed when my current dentist keeps talking about his yacht. But they're sure trained to provide a high level of care.

I don't actually agree with your examples but I wanted to add one of my own.

I went to a dentist complaining of sensitive teeth. He identified the problem as small cavities caused by chewing in my sleep, drilled them out, and added fillings.

A few months later those fillings fell out and I went to another dentist to get them replaced.

"You've had large holes drilled on top of your teeth so I'll have to replace them, but these fillings were totally unneccesary. If you get sensitivity like that again, just use a sensitive toothpaste. With your chewing you'll lose these fillings after about a year, and each time we'll need to drill out a little more, until by the time you are 40 you'll lose the teeth"

What on Earth does it mean to agree with his examples? He's not saying those stories happened to you.

Chewing in your sleep (or even when awake), called Bruxism, is extremely common for many people in stress causing professions. eg probably many people here

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

Did your dentist discuss getting a mouth guard/splint to wear at night?

https://en.wikipedia.org/wiki/Bruxism#Dental_guards_and_occl...

Asking because that's what I went with, and for me it works well. Without it when I wake up I feel as if I've not slept all (very unrested), with it I can actually feel rested after sleep.

That's only during stressful times though. ;)

I lost two teeth over the course of three years because the fillings kept falling out and they had to drill more to get it back in. I hate the current practice of dentistry being to 'make things worse to make things better'.

I can't wait for those things that grow enamel back naturally to fully work and become mainstream.

>Lukewarm water please.

Cold helps vasoconstriction. Warm equals vasodilatation equals more bleeding, and increasing the bloodflow makes it easier for the bacteria that will eventually come through microlesions to go around etc.

Things are in a specific way for a reason most of the time.

> It felt like she was taking an ice pick and stabbing my gums.

Yes because that's where calculus accumulates. It's not a pleasant feeling but it's not an unbearable pain either in my experience.

> It's not a pleasant feeling but it's not an unbearable pain either in my experience.

Indeed, the way worse version of that is having your gum bags cleaned out, it's literally scrapping everything out between your gums and your teeth, one of the more painful things I went trough in my life.

expletive deleted

I've had my guns cleaned 50+ times in life. when I tell you it hurt I'm saying it hurt unlike any other time .

you're assuming all pain is the same, all procedures are the same , and that all people experience the same amount of pain for a given proceedure.

not cool. your attitude is actually part of the problem.

Sounds like a combination of you just getting unlucky and having very low pain tolerance.

Personally I don't mind it hurting a bit sometimes, for smaller stuff I usually even opt out of the local anesthetics because I don't like running around with a mouth that feels like it's full of cotton.

Those are medical procedures after all, they are not supposed to make you feel amazing (at least during the process) they are supposed to "fix you", as such the process can be quite uncomfortable like many other medical procedures.

If pain is your issue you should try looking for dentists offering less-conventional methods, like hypnosis or electric anesthesia. But I doubt there's anything anybody could ever do to make a visit to the dentist "comfortable" for you, short of full anesthesia so you don't even notice what's happening.

I guess I got lucky because I don't really mind, never did. As kid I would hate going to the haircutter, but I loved visiting the dentist because of all the cool tools he had. Being weird sometimes has its advantages ;)

sorry but I hate this attitude. your comment of "I don't really mind, never did" makes it clear you think we're both experiencing the same amount of pain it's just that you're tougher.

let me assure you we are NOT going through the same amount of pain. if we were I am 1000% sure your attitude and reaction would be far different

Speaking of horror stories. I've had a dentist straight up leave the room and not come back half way through a cleaning.

I complained and didn't get charged, but WTF. I sat in the room with no explanation.

The only thing they did do was create a 3D model of my mouth from some 25 exrays they took.

In the US, it's uncommon for dentist to do cleanings. Are you sure it was t a hygenist?

I've been to dentists in Boston and Washington state, and I've never had experiences like this. My dentist in Boston (who is awesome) I found off of Yelp reviews. You should ask around for someone better.

Also, can get get less dentists that are condescending pricks? Like seriously, your job is to deal with this shit, deal with it, don't complain about it - that's my job and I'm not getting paid for it. You are, shut up.

You might be relatively insensitive to lidocaine. For the past 15 years and 3 dentists, I've almost always had to get additional lidocaine, sometimes 2 or 3 rounds of injections over a 20 or 30 minute period, even for simple fillings. That time might be split between the initial injection and subsequent injections midway through the procedure. Occasionally the dentists (certainly at least my latest one) breaks out a special alternative, which is injected with a much bigger needle from a comically huge injector.

A few years earlier I had a horrible root canal experience. For years I thought there was a mix-up and they had just forgotten to numb me. I went through the procedure without complaining because I thought it was normal, but I was soaking wet afterward from the sweat. Now I realize it's probably just that I was insensitive to the lidocaine (or whatever they gave me), and they weren't paying attention or didn't care.

I don't usually ask for the additional injections. But sometimes the pain is lightening quick, incredibly intense, and I can involuntarily jerk.[1] Unlike that first dentist, the past three refuse to continue without numbing me more if they sense I'm uncomfortable. I feel bad because sometimes I spend more time in the chair sitting alone, waiting for the injections to soak through and taking up a valuable patient slot than for the procedure. And I'm also a little worried that I'll become increasingly insensitive to these injections.

One trick I've learned that I think helps a little is to take some ibuprofen an hour or two before the appointment.

[1] I handle constant, dull pain much better. Though for all my teeth problems I've never had serious tooth pain outside a dental visit.

Stephan Guyenet had a series of blog posts called "Malocclusion: Disease of Civilization" on dental health. As I remember, as usual, decline in dental health was linked to moving away from traditional diets. The problem with teeth "overcrowding" was linked, basically, to not chewing enough of tough foods. People that ate plenty of tough foods as part of their diets had better developed jaws and space enough for all their teeth.

http://wholehealthsource.blogspot.dk/search/label/dental%20h...

How about people who chew on gum all day?

As usual, too much of anything is bad for you. Chewing gum all day leads to many other (severe) issues.

Don't chew all day = have one set of problems

Chew all day = another set of problems

We can't win, can we?

For many human movements, the relation between intensity and injury is a u-curve with high risk at extremely low intensity (atrophy) and extremely high intensity (overuse/repetitive strain), and low risk at moderate intensity.

> We can't win, can we?

"All day": There's your problem.

It's not so much the time as the toughness over time.

Have a steak or dense bread to exercise your jaws.

Or maybe beef jerky?

Yeah, but you could have great breath.

Cleaning your tongue is much more effective.

Chew sugarless Falim gum, one piece for each side of the jaw daily for aestethic gainz.

This dentist Dr. Palmer (who died a few years back) had a theory that breastfeeding is of crucial importance in shaping the jaw, http://www.brianpalmerdds.com/summary.htm though I’ve seen some theorizing elsewhere that nutrient deficiency might also be a cause (in addition to the theory from TFA about chewing hard foods).

I might add that the shape of the baby bottle nipple is crucially important for correct development of the palate as well.

I only know of the german company NUK making these. They are recommended by orthodontists. More info here: https://www.nuk.de/de_en/about-nuk/nuk-concepts/the-nuk-shap...

Also available in the US: http://www.nuk-usa.com/orthodontic-pacifier/orthodontic-paci...

NSFW warning, autoplaying breast-feeding video with audio. ;)

Ugh, that's disgusting. Who in their right mind wants auto-playing video with audio?

I know HN isn't the place for jokes, but this one genuinely made me chuckle.

Why does the author's wife think that chewing meat causes choking? This seems like a rather bizarre belief - does this have any basis in reality? If anything I'd think that learning to chew your food well from a young age would make you less likely to choke. (and more likely to moderate your food intake)

It seem like the equivalent of "don't let them walk, they will just fall and get a concussion"

There's a common risk mitigation technique which is something like "don't be weird around important stuff". So you can be weird in your cooking, or write a weird song, but when you are at the doctor's office, be normal.

It's not crazy. It would drive me crazy, because I like to learn the why's and how's of things. But I can acknowledge it's a decently adaptive strategy.

It's probably less and less effective though, as "normal" is becoming more and more just shorthand for "how the corporations think you should act".

Although that, too, is probably somewhat adaptive to get in line with.

Do you have kids? Everybody thinks everything causes choking. People stop you on the street to tell you how to feed your toddlers. Grapes were particularly suspect in our neighborhood. People cut them in half, believing it was safer.

You are right, I'm sure, about chewing being important to learn; and it would have to be a tiny piece in order for it to be hard to choke on it, anyway, so cutting it small certainly won't usually help.

I don't know how frequent kids choking is. All I know is that their gag reflex is pretty powerful and should keep them out of danger (for the most part).

Well, grapes do cause choking in young kids. Just the right size to wedge in the airway. But yeah I'm sure many warnings are overdone.

I don't doubt it! I just can't imagine that half a grape is safer than a whole grape for small kids.

A half is much safer because the skin is split.

The whole reason that grapes are dangerous for small kids is that the throat can't break the skin.

Of course, better to tell them to bite first.

I cringe a bit when I see people do the throwing the grape in the air and catch it in their mouths.

She believed that their children would try to swallow without chewing their meat enough, and thus choke if the meat was in too big of pieces.

Tat reminds me of the time when one of our kids was about 6 and slammed down a couple of hot dogs without buns and ran upstairs to return to playing and barfed. The hot dog pieces that came out were very clearly not chewed. It was an interesting learning experience all around.

When I see old human skeletons always wonder how they kept their teeth so good. Without toothpaste, toothbrush or floss. What are we doing wrong?

I wonder if sugar's ubiquity has anything to say about this.

My dentist said sugar laden soft-drinks and sugar-laden processed food are the worst culprits.

Especially the soft drink. Apparently the acid and sugar in soda are the worst things you could put on your teeth. It's like a double whammy.

As soon as I quit soda in my 20s, my cavities stopped. My dentist said I could have as much water and beer as I wanted, but no more soda.

They are relevant for cavities, but the article is talking about all the other issues with our teeth, like not being aligned properly. Sugar has nothing to do with those problems, according to the article.

Read the article and find out :^)

Carbs

The only reason I can see you being down voted is because you're not providing a constructive argument in HN standards against carbs. But you do make an excellent point. I'd like to add that in addition to the dental antropologist listed in the article [0], Weston A. Price [1] is also very well known for the role of agriculture (more carbs) in human dental change.

[0] https://en.wikipedia.org/wiki/Robert_Corruccini

[1] https://en.wikipedia.org/wiki/Weston_Price

My driving instructor grew up on a farm in Portugal and claimed that he didn't brush his teeth until he was an adult. Shocked, I asked if he had many dental issues and he claimed that he had none because everything he ate came from the farm.

There's evidence that cleaning with toothpaste is no better than cleaning with water alone (keyword for search "dentifrice": https://www.ncbi.nlm.nih.gov/pubmed/27513809

There's evidence that plant root fiber toothbrushes are at least as good as nylon bristle toothbrushes (keywords for search "miswak", "chewing stick"), eg: https://www.ncbi.nlm.nih.gov/pubmed/15643758 (in my personal experience they work just fine, but they are more hassle than nylon toothbrushes because the bristles point in the same direction as the handle instead of to the side)

There's also evidence that flossing+brushing has no advantage over brushing alone: https://www.ncbi.nlm.nih.gov/pubmed/19138178

Of course, medical research is notoriously unreliable, but it's at least plausible that ancient humans had all the technology needed to keep their teeth in good condition.

Also, they didn't have refined sugar in their diet.

Id say this is the most important part.The sugar epidemic of our age is pretty crazy.

Also, isn't the first medical surgery in history, we have evidence of, related to the teeth ?

Some of the earliest prosthetics are dentures as well.

You can also use charcoal and salt to brush your teeth, apparently. http://timesofindia.indiatimes.com/business/india-business/C...

While it is true that plaque can be removed with or without toothpaste, that fact is a little misleading in isolation.

The benefit of toothpaste is the topical application of fluoride. When applied topically in concentrations greater than 1000ppm, fluoride replaces a molecule in hydroxyapatite and creates fluorapatite. Fluorapatite is much more resistant to dissolution by acid. That is important because cavity-causing-bacteria in plaque gain entry into a tooth by bathing the tooth in lactic acid.

You're going to say "ewwwwww gross!", but: I do not brush my teeth. Haven't since I was 10 years old, I'm 34 now. The most I ever do is chew sugar free gum, or pick at my gum line with a fingernail in idle moments alone. You know, like humans did for a few million years. I have very little sugar in my diet.

When I go to the dentist every five or so years, they say "gosh you take good care of your teeth" and I smirk. Never had a filling, never had gum disease.

If I didn't chainsmoke and drink coffee like a gutter they'd not be slightly ivory coloured, as they are, rather white.

I view the dental hygiene industry rather like the anti-spot creme industry - once you start screwing with something, you have to keep screwing with it.

A final aside: I have 28 teeth, including wisdom teeth. Never had first molars, nor my mother or grandfather. Means the wisdom teeth fit just fine, and many a dentist who's not only convinced that I brush thrice daily but also had dental surgery. Apparently this isn't a common mutation.

This sounds like sure fire way to have Halitosis. :(

Enamel can erode for years and still protect your teeth until suddenly it's worn away and doesn't protect your tooth anymore. I got similar feedback from dentists while not having great hygiene and suddenly in one visit after years and years of "doing great" I had four cavities.

My girlfriend has been bragging in a similar way and I've been trying to warn her to be more careful, and she knows exactly what all I went though (fillings kept falling out, eventually lost the teeth and needed a bridge).

I bet that is not working out as well as you think.

How many old skeletons do you see? Are they a representative sample?

Pre-industrial skeletal remains are often seen with more teeth than we might expect.

Here are the ways you lose a tooth: 1. Trauma, like a hit to the face, that knocks a tooth out. 2. Abrasion on the biting surfaces that wears teeth down to a stub over a lifetime. 3. An infectious disease that destroys the teeth (cavities). 4. An infectious disease that destroys the supporting bone around the teeth (periodontal disease).

What we are doing wrong: 1. Not wearing mouthguards to play sports/drive cars (think about hockey players who are missing teeth). 2. Living longer means more wear (also the position of the teeth changed in a softer, post-industrial diet). 3. Fermentable carbohydrates are eaten more frequently throughout the day. Bacteria that cause cavities, like streptococcus mutans, ferment carbohydrates into lactic acid, dissolve the underlying surface of the tooth, and invade deeper into the tooth. 4. Periodontal disease typically starts to take its toll in the third decade of life. We live longer than our ancestors.

I had to get my front molars and wisdom teeth removed to make room in my jaw (got braces, all good)

Saw the x-ray of my wisdoms. The tops were facing my front teeth, ie 90 degrees rotated

I have the same issue with my wisdoms. Seems to be a common thing. Weird.

Was it painful to remove wisdoms?

Not GP, but I've had 4 removed and it wasn't painful (under local anaesthetics). Just really uncomfortable, especially when you hear and _feel_ the crunch of a tooth being uprooted.

I had the same thing. There is little to no pain in the extraction, at least there was not for me. My wisdom teeth were quite big so I was completely sedated for the procedure itself. Followed by a few days of ice packs, lots of gauze in my cheeks, and nothing but milkshakes for meals and I was back at school and happy as a clam.

It was when the anaesthesia ran out halfway thru

It's mind blowing to me that this happens. My condolences. :)

Wisdom teeth spread their roots the older they get.

Basically the roots look like this at first || and after they get settled in, they're more like this: _/\_ and at that point getting them out WILL suck.

So if you have any family history of your wisdom teeth being f'd up, get them removed as soon as possible. My top two wisdom teeth were out before I even noticed the dentist was doing anything.

Then I got stupid and chickened out, waited too long, and the bottom ones were an hour each to dig out piece by piece. Not fun.

I had the opposite problem: they were still very low down when they started impacting the other teeth, and as a result they were still rooted in the cranial nerve. I had to wait longer for them to grow out further and impact even harder before I could get them taken out without high risk of facial paralysis. As it was I still lost feeling in one half of my tongue.

And you still have lost feeling? Do you bite it a lot?

It was worse in the beginning, now it is more like the front-left 1/3 is numb. No, I don't really bite it. It made speaking in the beginning difficult, but I've learned how to work around it.

I've had two removed. One just popped out when pulled with the extraction tools, the other totally shattered, which then required an operation under general anaesthetic to be fully removed[1].

Of the remaining two, my top left one is fully 'through' but at a slight rearward facing angle. I don't know if that is normal or not. The other (my bottom left) is 99% still under the surface, and like another commenter just said, is sideways orientated with the top of the tooth facing the front of my jaw. What sucks about this tooth is that because it's slightly erupted I do get food caught between it and my rear molar so I have to be very thorough when cleaning. It doesn't move at all (it's been like this 20 years now) or hurt, so I just live with it.

Here in the UK simple tooth extractions tend to be done with just local anaesthesia via injection into the gum[2]; Only the more complicated removals end up in hospital as a general anaesthetic based operation done by a Ear-Nose-and-Throat specialist.

The pain only really hits once the anaesthetic wears off. Tooth pain is one of the worse kinds of pain I think. It only lasts a few days though as the mouth has an amazing ability to heal compared to other parts of the body.

---

[1] I also had a largish mole on my brow removed as a freebie at the same time. Bonus!

[2] UK Dentists don't use gas.

I had all four wisdom teeth extracted in the same procedure under local anaesthetic, back in the medieval days of 1980s British NHS dentistry. The four deep injections were significantly more painful than the extractions and in fact led me to avoid dentistry in general.

However, many years later, I experienced excruciating tooth pain due to air pressure change [1] while flying to the US and then while subsequently driving through Yosemite. The pain was so bad at one point I had to stop driving and the prospect of the flight home was not fun. The cavity was exacerbated by my avoidance of dentistry following the wisdom teeth. The dental injection when I got home was nothing compared to the prior tooth pain so I started properly going to the dentist again. A root canal procedure several years later involved injections that were virtually pain free so I now don't stress about the prospect of an injection at all (except perhaps for the few seconds when the dentist is about to insert the needle).

For me, the change is due to 1) improvements in procedures and 2) a general lessening in personal squeamishness as I've got older. Any injection at all when I was younger had the potential to make me faint but now I can even watch the needle during a blood test or similar. YMMV.

[1] https://en.wikipedia.org/wiki/Barodontalgia

All four in one go, procedure wasn't painful for me at all, but that might have something to do with it being under general anaesthetic. Of course, mouth was a bit painful for a few days.

I wonder what else might be going wrong with our bodies as a result of our childhood habits. For instance, are my hips genetically shallow or did I spend too little time outside running about as a kid?

Wait and see if elongated thumbs exist for the next generation.

What do you big toes look like? Do they line up with the Extensor Hallucis Longus Tendon, the major ridge the runs along the interior of the top of your foot, or do they curve inward?

This is interesting. Teeth are of pretermined shape and size to fit the jaw, or the jaw the teeth "assume" will be there. The jaw's shape and size is determined by what/how you eat. For humans with a "traditional" diet, that assumption is correct. For us, it isn't.

This is very specific to humans though, and the specific problem of "overcrowded" mouths. But teeth have other issues, and in other species too. For many animals, teeth are the thing that fails at old age effectively capping lifespan.

I'd like to know what are the "[f]or adults, surgical options for stimulating bone growth are gaining momentum, too, and can lead to shorter treatment times." .. referred to in the third-to-last paragraph? Is this something more than breaking the jaw and extending it like is sometimes done with legs to treat severe growth problems?

That was always the recommendation I got, even as a teenager pre-braces. In the end, my parents opted for braces, which I had to wear twice for a total of 9 years. In the end, my 4 lower front teeth lost bone, so they were dangerously loose. I had a massive retainer to keep them stable for about 6 years. Last year, I finally had them removed and replaced with implants and crowns. I am much happier now, but it took over 15 years of pain, and roughly $30k. I have an expensive mouth.

I remember talking to an army recruiter at school when I was about 14 - not to recruit us, but to show how "cool" a career in the military could be, in case book-lernin didn't work out. Anyhow, the one thing I remember him saying is in boot camp they were made to chew every bite of food 50 times. The drill sergeant would count and punish anyone who swallowed before they got to fifty.

Fast-forward 30 years and I STILL continue to chew my food an inordinate number of times because of that one interaction. However, I've never been able to verify whether or not he was pulling my leg. I don't have a particularly large jaw, but I have noticed (anecdotally, of course) that I have fewer stomach issues than my peers who tend to chew-chew-gulp everything.

My mum's number was 32, which meant early on (age 3) I learnt binary halving to know if I was a quarter done, halfway done, etc.

when to start giving babies beef jerky

Sidenote: I recently finished reading The Story of the Human Body by Daniel Lieberman, in which he addresses this issue (among many others). The book is absolutely fantastic, an engaging, highly-readable page-turner packed with insights and epiphanies about how we can think about contemporary challenges from an evolutionary perspective.

It has always amazed me that teeth have such a high failure rate when they contain 0 moving parts. There's also no biological or chemical processes that need to happen. They're literally just an inanimate object that you use for biting. How can they be so unreliable??

Teeth themselves maybe, but that's kind of like saying a drill bit is inanimate without moving parts.

But it's not the jaw that fails... it's the teeth, or the tooth-jaw interface. Neither of which have any moving parts!

Drill bits break much more often than drills themselves do.

The tooth-food or tooth-tooth interaction "counts" as a moving part - it gets friction, it gets all kinds of forces/stress applied, exactly as the interaction between moving parts in a mechanism.

Teeth aren't inanimate. They contain a living core and support a distinct microbiome, not all member species of which are innocuous.

For starters, teeth are alive and the soft core (dentin) is in continuous regeneration like any live tissue.

Teeth are also not not moving. During chewing the jaw itself flexes quite a bit, and teeth don't have a rigid connection to the jaw (there is a gap between the root and the jaw filled with collagen fibers), and this flexible connection bears all forces a tooth is subjected to.

I'd also argue that correctly maintained teeth and periodontia are very reliable given their long life span.

Is there any recomendation of chewing exercices for children? duration, frequency and a chewing "device" (it could be a specially tough vegetable too).

I guess a couple of minutes of strong chewing before each meal could improve the growth of the jaw in small kids.

If you want a more simplistic overview of the cause of cavities, this seemed to be quite accessible. https://www.youtube.com/watch?v=dtdwHR7Fpyo

Can this really be true? Is there any science on this beyond a blog post?

There are literally links to scientific research in the article.

This isn't an opinion piece. The author is a researcher in the field.

Thanks, couldn't see the links on my phone but re-opened on computer (I was quite surprised by your response -- thanks!) and there they were.

Just had two wisdom teeth out last week. I hadnt been to the dentist in years and years (my old dentist died years ago) I went to a new one because of some pain, turns out one of my lower wisdom teeth was burrowing into the molar in front of it and causing a cavity under the gum which was the source of the pain. Now I need to see if I can get that cavity fixed, or else have that molar pulled too.

Blogspam of

https://aeon.co/ideas/its-not-that-your-teeth-are-too-big-yo...

Well, it was licensed, but ok we'll change it from https://www.sapiens.org/body/human-teeth-evolution/.

What is "blogspam"? New to HN, and trying to maintain good posting etiquette. I posted the same link from sapiens.org a while back.

http://www.urbandictionary.com/define.php?term=blogspam

"A blog where the author paraphrases or copies from the original article/webpage in an attempt to increase his or her own traffic. This becomes a waste of the reader's time forcing them to click through the blog to get to the actual article. Often submitted to sites like Digg or Reddit."

Thanks, I will keep this in mind when I post.

Using "blogspam" in this context was inappropriately harsh, and I apologize.

But when submitting to HN one should use original sources wherever possible. In this case, the original source was stated right in the opening of the article.

True blogspam is when blogs (sometimes, even entire sites), trolling for clicks and presentations, copy content and/or misdirect readers for the purpose of garnering undeserved presentations.

Some of these even misroute you to malware using URL shorteners. There is no legitimate reason to use URL shorteners here.

Got it. Thanks for the clarification:)

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