Thread by @DorsaAmir

Ever wonder why humans are the only animals that need braces? 🦷 Turns out this is a relatively recent problem for us. (1/5)

If you look at the fossil record, you’ll find that our ancestors’ teeth look surprisingly good. While there’s some evidence for ancient dentistry using tiny flint tools (ouch), there was very little need for ancient orthodontists. (2/5) nature.com/articles/srep1…

So what happened?

Well, to put it simply: industrialization. As our diets changed, so did our eating habits. We started to cook softer foods & eat with utensils.

This led to a big change: we stopped chewing as much. (3/5)

As a result of these changes & others, our jaws became smaller and smaller, giving our teeth less room to grow normally. This has led to the epidemic of crooked teeth we see today. (4/5)

So what can we do?

One thing that could help is encouraging kids to chew more, as this may help strengthen and expand their jaws.

In the words of @PeterSUngar: “Let them chew!”(5/5)
sapiens.org/body/human-tee…

Some more resources on this topic:
- Why Cavemen Needed No Braces: stanfordpress.typepad.com/blog/2018/05/w…
- And this fascinating study by Dan Lieberman: “Effects of food processing on masticatory strain and craniofacial growth in a retrognathic face” sciencedirect.com/science/articl…

A quick postscript to address a good question that's coming up.

We are the products of both evolution & development.

It is true that our jaws have shrunk over evolutionary time. It is *also* true that more recent lifestyle changes have made them problematically smaller.

Data suggests that the teeth of those in contemporary foraging populations are more healthy than those in industrialized populations.

So this is likely a "secular trend" — a quicker change that's happening as a result of a changing environment.

Self-described "tooth aficionado" @PeterSUngar —who literally wrote the book on this — weighs in👇

https://twitter.com/PeterSUngar/status/1185176832229855233?s=20