
Why Are Human Teeth So Messed Up? - drchip
https://aeon.co/ideas/its-not-that-your-teeth-are-too-big-your-jaw-is-too-small
======
synicalx
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.

~~~
jstanley
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.

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

~~~
jstanley
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.

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

------
yousifa
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.

~~~
everyone
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.

~~~
azernik
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.

~~~
dredmorbius
Would you happen to have a reference on that?

~~~
wahern
A quick Google Books search found,

    
    
      Tosefta Berachot: Translated Into English with a Commentary
    
      https://books.google.com/books?id=ronqNAPipaEC&pg=PA189

~~~
wahern
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

------
tominous
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](https://www.dentistat.com/ReaderDigestArticle.pdf)

~~~
anon1253
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...](http://www.sciencedirect.com/science/article/pii/S0951832007001007)
the money shot is in this chart
[http://imgur.com/a/shaii](http://imgur.com/a/shaii) but you'll see similar
distributions everywhere where expert judgement is warranted.

~~~
erikpukinskis
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.

~~~
digi_owl
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.

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

------
greggman
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.

~~~
shubb
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"

~~~
justinclift
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](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...](https://en.wikipedia.org/wiki/Bruxism#Dental_guards_and_occlusal_splints)

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. ;)

------
Evgeny
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...](http://wholehealthsource.blogspot.dk/search/label/dental%20health)

~~~
amelius
How about people who chew on gum all day?

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

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

Chew all day = another set of problems

We can't win, can we?

~~~
RyanMcGreal
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.

------
jacobolus
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](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).

~~~
car
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...](https://www.nuk.de/de_en/about-nuk/nuk-concepts/the-
nuk-shape.html)

Also available in the US: [http://www.nuk-usa.com/orthodontic-
pacifier/orthodontic-paci...](http://www.nuk-usa.com/orthodontic-
pacifier/orthodontic-pacifier.html)

~~~
aw3c2
NSFW warning, autoplaying breast-feeding video with audio. ;)

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

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

------
Sleeep
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"

~~~
matt_morgan
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.

~~~
emmelaich
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.

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

~~~
emmelaich
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.

------
guilhas
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?

~~~
mrob
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](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](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](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.

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

~~~
azm1
Id say this is the most important part.The sugar epidemic of our age is pretty
crazy.

------
elchief
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

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

Was it painful to remove wisdoms?

~~~
theshrike79
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.

~~~
snovv_crash
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.

~~~
Noumenon72
And you still have lost feeling? Do you bite it a lot?

~~~
snovv_crash
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.

------
leksak
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?

~~~
undersuit
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?

------
dalbasal
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.

------
rfreytag
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?

~~~
HorizonXP
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.

------
jspash
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.

~~~
juanuys
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.

------
wgaggioli
when to start giving babies beef jerky

------
RyanMcGreal
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.

------
jstanley
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??

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

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

~~~
jessaustin
Drill bits break much more often than drills themselves do.

------
omegant
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.

------
lathiat
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](https://www.youtube.com/watch?v=dtdwHR7Fpyo)

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

~~~
sn9
There are literally links to scientific research in the article.

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

~~~
gumby
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.

------
everyone
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.

------
DrScump
Blogspam of

[https://aeon.co/ideas/its-not-that-your-teeth-are-too-big-
yo...](https://aeon.co/ideas/its-not-that-your-teeth-are-too-big-your-jaw-is-
too-small)

~~~
fern12
What is "blogspam"? New to HN, and trying to maintain good posting etiquette.
I posted the same link from sapiens.org a while back.

~~~
DrScump
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.

~~~
fern12
Got it. Thanks for the clarification:)

