Why do we have crooked teeth?

Have you ever wondered why modern humans often have dental issues like tooth crookedness?

Well, there isn't a definitive answer to that question as of yet, but scientists have come up with a few theories regarding the subject, most of them related to dietary choices and the advent of processed food in our lives.

With all the fossilized skull samples acquired from our ancestors through archeological findings, it was possible to see obvious changes developing throughout millions of years of evolution, specially on our bone structure, such as the jaw line and our teeth.

Our ancestors used to have perfect straight teeth for very practical reasons, unlike nowadays, that is all about the pretty smile on your Insta feed or yearbook picture. No, their technique did not involve braces. They had to apply much more effort to be able to chew and digest their raw food, specially grains and seeds. Those were a lot harder to process and mince, causing a lot of abrasion, which seems to be the most plausible reason why their teeth were so flat and worn out, but much, much stronger. The larger jaw was key to be able to apply the necessary force and pressure to crush the raw food, but also to have the space needed to fit the third molars - as knows as our wisdom teeth.

As evolution followed it's natural course through millennia, tools for crushing, mowing and breaking became a part of daily life, along with the of advent of fire. Other agricultural practices such as farming and animal domestication became mundane as well, making a lot easier to produce and refine their food, leading the primordial populations to consume a lot more wheat and rice in their processed form as a direct result.

Set your time machine to a handful of thousand of years later, industrial revolution and it's commodities come with massive changes in consumerism and the way we prepare our food. From this point onward, the need for strong teeth lessened greatly, since technology started doing all the hard work for us. And that is exactly when history has documented that crooked teeth started becoming increasingly common. Evidence shows that as our jaw line shrinked rapidly, our teeth did not quite change with the same speed, which made them have to fight over the limited space that was left in our mouths, therefore causing the displacement and unevenness on our smiles. Is worth noting that the less apparent issues like the misalignment of the bite can be also a consequence of these factors. The situation can become even more tricky once the wisdom teeth decide to make their debut, causing surgical removal to be necessary, in many cases, to avoid discomfort and even the insurgence of infection.

This hypothesis has been supported by studies made in 1983, where a small group of squirrels were submitted to testing, as half of them ate hard, chewy foods, whilst the control group was only fed with the softer alternative, like fruits, resulting in visible changes in both their teeth and the format of their jaws. A similar study was conducted in 2004, with a hyraxes group, showing the same results. In conclusion, the issue can be caused either by lifestyle or enviromental changes, that also end up becoming genetic, through heritage factors. The latter could also explain the opposite effect as well, making it more common for people to not have wisdom teeth at all or even to have them without any further complications. If they have that super hero jawline, that is.

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Original content referenced in the article was produced by the TED-Ed youtube channel.

Happy learning!