As a general rule, prehistoric people didn’t have crowded teeth. They generally developed straight teeth, and the amount of people with appreciable crowding was very small: about 1% according to the authoritative study on the subject. Compare that with about 65% of modern people who would benefit from orthodontic treatments like braces or Invisalign, and you can see that there’s a very big difference.
So why do modern people need orthodontic treatment so much?
An Exception That Proves the Rule
To help explain the changes that people have undergone to lead to crowding of the dental arch, it can be helpful to look at an extreme example of crowding in a prehistoric population. At this site, located in the south of France and dating from about 2150 BC, people had crowding that was even worse than modern populations.
Here’s how crowding in this sample compares to modern people:
Ideal: 0% (prehistoric) vs. 33.7% (modern)
Minimal crowding: 35.25% vs. 27.3%
Moderate crowding: 34.8% vs. 23.3%
Severe crowding: 16.3% vs. 11.4%
Extreme crowding: 16.4% vs. 4.3%
What a difference from the normal Bronze Age population. Instead of 1% crowding, this population had 100% crowding, with nearly four times as much extreme crowding as a modern population.
Researchers explain this variation with one simple fact: the jaw width of this prehistoric population was about an inch smaller than modern populations. Normally, prehistoric people have larger jaws than modern people. But this population is different.
The population in question here were farmers and breeders and led a sedentary, solitary life. In fact, evidence of warfare shows that these people were likely constantly fighting their neighbors, increasing their isolation. An individual with a small jaw in the original population at this site could have resulted in the spread of the trait through the isolated population, causing an epidemic of tooth crowding.
Why Modern Jaws Are Smaller
So a single mutation accounts for the smaller jaw in this prehistoric population, but why do modern people have smaller jaws? There are two good explanations.
Humans all have smaller jaws than our primate cousins. This development began with Homo erectus, the first humans who cooked. Because they cooked, they spent less time chewing tough food. Chewing tough food stimulates the growth of the jaw, so with less chewing, they developed smaller jaws.
As moderns, we spend a lot less time chewing on tough food. Our modern processed food is as a rule much softer than that which our ancestors ate. In a population like this one, people routinely wore their teeth down so that their enamel was all gone and the dentin underneath was badly worn away, too. The wear is even more remarkable when you consider that the life expectancy of this population was about 25, and only 1 in 7 lived past the age of 35. Even people who live to their 80s or 90s these days do not experience this type of wear unless they have extreme bite problems.
Another reason why our jaw is smaller is that the smaller jaw is adaptive for speech. It’s easier to control the sound in our smaller mouth than it would be in a larger jaw.
As a result of these two factors, modern people have smaller jaws than our ancestors, and, unfortunately, when you try to put the same number of teeth in a smaller jaw, crowding results, which is why wisdom tooth removal is often recommended to relieve some of the crowding.
Even so, many people still experience crowding and seek out orthodontic treatment for relief. If you are unhappy with the crowding of your teeth and want to learn more about orthodontic options like Invisalign, please call 310-275-5325 today for an appointment with a cosmetic dentist in Beverly Hills at Ravon Knopf.