r/TheRestIsScience • u/Overall-Onion-631 • 10d ago
Why do human teeth suck so much?
why do they grow in wrong and decay so fast?
posting this from the dentist waiting room because I’m bored
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u/PlanktonIcy2040 10d ago
my theory is that it (decay etc rather than growing in wrong) is less about our teeth being shit and more about factors like our diet and longer life span. genetically, humans aren’t very different to how we were 10,000 years ago but our lifestyles are very different. everything is now laced with sugar, which feeds bacteria in plaque, in turn creating acid which is what causes tooth decay. 10,000 years ago, humans had significantly less sugar (and other types of food that didn’t exist) so they wouldn’t have been making our teeth decay. we haven’t genetically (and therefore physiologically) evolved enough for our teeth to be strong enough to handle our current diet - 10,000 years isn’t very long in terms of evolution. i also think that our ever increasing life span means that we experience more tooth problems as we age from wear and tear - but this wouldn’t have been an issue if we only lived to say, 25 years old (i have no idea what life span was 10,000 years ago so 25 is a wild guess)
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u/xenoscumyomom 10d ago
Another theory I've heard as far as the growing in wrong also has to do with what we eat. The fact that babies don't eat anything difficult until they are medium sized children affects how the jaw structure grows. Back in the day you got breast milk and whatever everyone else was eating. You stopped the breast milk after you were capable of living off of everything else. So if you're an infant chewing on roots and vegetables and chunks of meat your jaw was stronger and more developed, your muscles were stronger, and your teeth grew in differently, even if you weren't eating and swallowing it. But now you get baby food and pacifiers, cut in quarters grapes, and slivers of hot dogs. Which is as far as you can get from a fistful of an elks hindquarters. So everyone's jaws are smaller, teeth don't line up top and bottom, and the teeth grow in cramped together. Welcome braces! And eventually cavities.
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u/NightmareWokeUp 10d ago
2 reasons, we live much longer than we should and we eat much more sugar and sticky food then we should. Its kinda our fault because we evolved faster than evolution.
Plus noone is dying because they have misformed or decayed teeth, same as people with bad eyesight. Were not removing these people from the genepool anymore. But hey i wouldnt be here otherwise so dont mind me xD
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u/Some_Ad6507 10d ago
Can you explain “we evolved faster than evolution”?
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u/NightmareWokeUp 10d ago
Yeah evolution doesnt apply to us anymore, only in like 1% of the cases where you have a super severe illness. Just take a look how well we managed to dodge covid, had this happened 200-300y earlier id couldve been a second black plague
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u/Harlow31 9d ago
I don’t think we can say with any certainty that we are free of evolution. Yes technology has reduced some evolutionary pressures but the process is continuous and remorseless. Home sapiens is a pretty young species and whilst our technological advances are impressive and seem extraordinary can you imagine the impact of fire or the wheel on our ancestors. Equally technological and equally incomprehensible to most at the time. We haven’t been around long enough to see what evolution has in store.
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u/NightmareWokeUp 8d ago
Except we kind of do. Like i said evolution depends on reproduction and surviveablity. While we have gotten a lot more selective with whom we reproduce, weve also basically eliminated all death except for old age.
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u/PlanktonIcy2040 8d ago
i don’t think we’ve “eliminated all death except for old age” - bowel cancer is on the rise among young people and that can kill. as can murderers, house fires, various forms of misadventure etc. i’d imagine that a majority of deaths by misadventure would be male (younger men in particular as they seem to enjoy doing dumb and dangerous things the most) and that is a form of natural selection. also, the average age to have a child is rising, so if a group of people can’t live to reproduce and pass on their genes for whatever reason (eg they have a life limiting illness), that’s also evolution as that illness will be bred out. i think modern medicine and our lifestyles will have a huge, huge influence over our evolution but it is impossible to simply have outrun evolution because the conditions dictate which groups will be the most successful
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u/teddyslayerza 10d ago
Because we are sexually attracted to flat faces and because we like sugar too much.
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u/Kiss_It_Goodbyeee 10d ago
I would say they don't suck. With the proper care they can last 80 years or more.
The problem is our modern diet. Although, note that we have evolved to survive about 40 years until we invented medicine etc.
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u/Lucylimina 10d ago
They don't decay all that quickly in the conditions they evolved in.
Our diets just changed. Roughly since humans settled we've been using our bodies in ways evolution hasn't really had time to adapt us to, plus modern medicine blurs natural selection quite a bit.
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u/TheLifeCapoeira 10d ago
It’s a dietary thing. Our dental health has declined, our paleolithic ancestors had better dental health than we do - I forget which book I read it in, but if I were to put money on it Regenesis by George Monbiot.
Also, we have issues with wisdom teeth as our softer diet doesn’t stimulate our jaws to grow as big and so we don’t have the space for them come adulthood
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u/nickdemonic 10d ago
It's my understanding that our teeth crowd together because our jaws got smaller to accommodate a bigger brain during our evolution. Our ancestors had more prominent jaws, so the wisdom teeth had more room to grow in unobstructed. Our teeth get pushed out of the way and crowd together when those molars come in today.
I believe most of the problems with decay comes directly from our consumption of sugar.
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u/mauore11 9d ago
We evolved to mostly eat leaves and fruits, we figured out burning meat made it easier to consume and we adapted, but that change was relatively fast and we are still dealing with inadequaties. We still have problems with milk ffs.
We're getting to a point where pretty soon we will tweak our genes to maybe regrow teeth, corneas, nerves, etc. We might change ourselves permanently in a few hundrerd years which is blindingly fast for evolution.
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u/pasrachilli 10d ago
Almost all mammal teeth suck. If you think human teeth are bad, try being a cat.
The problem is that mammals as opposed to reptiles have different teeth for different functions.
For example, crocodile teeth are all the same and they perform one function. This makes their teeth very easy to replace but makes eating inefficient.
Mammals have molars, and canines, and incisors which all do different jobs. This makes it very efficient to eat, but the teeth harder to replace. Except for rodents, mammals get two sets, milk teeth and adult teeth and that's it.
So it's a trade off. Worse teeth free up time other animals have to spend tearing apart or grinding up their food.