The human anatomy, like all other species, evolves and changes over time. As science and technology continue to progress, scientists can uncover more and more about the genetic and biological history of the human body. For biologists, dentists, and archaeologists alike, the history of the human mouth is of interest.

Have you ever sat through a single tooth implant, cavity filling, or extraction and thought: why can’t my teeth just be perfect? Turns out, scientists are puzzled by this, too. Other toothed species, from dogs to lions, often have perfectly aligned teeth and jaws. Though we are not so biologically different from animals, most humans have at least some form of orthodontic misalignment. For example, wisdom tooth problems are common– in many people, rear molars (wisdom teeth) don’t have enough room to emerge or develop normally.

A few recent archaeological and biological studies have helped explain why human teeth aren’t as straight as animals. First, humans today have much smaller teeth and jaws than people who lived 25,000 years ago. In pre-agricultural contexts, human jawbones and teeth were big, especially incisor and canine teeth. Interestingly, humans from the eras before agriculture also had straighter teeth because they fit more naturally in the mouth and jaw.

Today, indigenous groups that live lives more like ancient humans also have better teeth– a study of the Hadza foragers in Tanzania, for example, found that their mouths had more teeth, their jaws more space, and they all had an ideal “tip-to-tip” bite between the upper and lower front teeth. There is an explanation for these differences: bones that experience greater pressure grow stronger and larger. People with tougher, plant-and-meat diets experience greater jaw strain, which helps their jawbones grow to make space for all those teeth.

This is not to say that we should abandon our current dental practices in hopes of straighter smiles– one study showed that Inuit and Australian aboriginals’ teeth were worn down much earlier in life. Teeth on traditional diets may be neat and straight, but they last no longer than other human teeth. Even if you switched to an all-natural diet, you could lose one of your pearly whites and require a single tooth implant to have it back.

Although our jaws don’t grow as big as they used to, we can still trace other parts of our dental anatomy to the habits of our human ancestors. For example, many believe that not all human ancestors had bicuspids and incisors– those only developed when groups that previously gathered plants to eat shifted to animal-based diets as they roamed or as their environment changed.

In conclusion, our mouths reflect our ancestor’s constantly changing omnivorous past. Though our teeth last longer than they used to, thanks to dental hygiene, many of us still must go through different types of oral surgery procedures to get straight smiles. From single tooth implants to jaw reconstruction, we go out of our way to re-create what our ancestors had naturally. Isn’t that fascinating?