Is the Overbite Part of Natural Evolution, or Are We Forking Over Too Much in the Name of Convenience?
Much of the work in modern orthodontics is dedicated to re-creating an ideal, naturally occurring overbite in patients. But here’s a question worth chewing on—is that overbite really so natural? Or was the modern human overbite, so prevalent around the world, really caused by the fork and knife? Could table manners really bring about a change in anatomy? According to the famed anthropologist C. Loring Brace IV, the answer is yes.
A specialist in the evolution of hominid teeth, Brace studied this question over the course of several decades. Although he’s now retired from his post at the University of Michigan, Brace’s findings are reshaping one of the areas typically reshaped by orthodontists—the human jaw.
Until about 250 years ago, humans did not have anything resembling a modern overbite. From the time of Neanderthals to the time of George Washington, an edge-to-edge bite was the norm. That’s the same bite that monkeys and apes have, with top and bottom teeth aligned and clashing together like a guillotine blade.
Overbites had long puzzled Brace. His initial theory was that the modern overbite began thousands of years ago with the onset of agriculture and the introduction of grains in the human diet. But as he studied more and more jaws on his way to building the world’s largest single database of craniofacial and dental measurements, he found that the edge-to-edge bite continued to be the norm long after farming began.
Instead, the modern overbite started showing up in European jaws in the mid-1700s—the same time that Europeans began using forks.
His conclusion: It wasn’t the type of food people were eating that caused the change in bite; it was the way they ate that food.
[ The Stuff and Cut Approach ]
Before the fork, humans used what Brace calls the “stuff and cut” approach to eating. They used their teeth to clamp onto a hunk of food. Then, with their hand or a knife, they tore or cut the food into a chewable piece. (That means the incisor is misnamed, Brace argues. While the word “incisor” comes from the Latin “incidere,” meaning “to cut,” the incisors were actually used to clamp food, not to cut it, he says.)
Once people turned to table knives to cut their food into small pieces and forks to carry the food to their mouths, incisors were no longer used for clamping. And without use, the incisors continued to erupt, until the top layer no longer met the bottom layer—creating an overbite. And that overbite became the new normal.
“Even the dental profession assumes that the overbite is ‘natural’—well, it isn’t,” Brace said in an interview with the journal Current Anthropology. “What happens is this: the first permanent teeth that come in are the first upper and lower molars. They are the most regularly shaped and have an intercuspal relationship. They serve to keep the upper and lower jaw in an aligned relationship to each other while all the other deciduous teeth are lost and the permanent teeth come in. As these come in, they are set in position by use. Now, if people at an early age hold things in their mouths with their front teeth, they will wind up with an edge-to-edge bite, not an overbite.”
As Brace studied more and more jaws from around the world, he discovered the appearance of a similar overbite in China, but it appeared 900 years before the fork and the European overbite.
The cause? Chopsticks—another utensil that meant less clamping with the incisors.
As his research reached out to more and more corners of the globe, Brace discovered evidence that supports the theory. Sometimes, that evidence is from a single generation in a single family.
“We found that it was possible to tell when an Australian Aborigine family came out of the bush and joined in a mission station,” he said in the Current Anthropology interview. “The older children would have great wide, short faces and perfect occlusions while the younger ones had narrow faces with an overbite and crowded teeth—and this in the same family! The older ones had used their teeth right from the start in the bush on partially cooked gristle, the younger ones were raised on oatmeal. The difference was the stimulation to the erupting teeth.”
[ A History of the Fork ]
Brace’s theory of the overbite received a good amount of attention in the 2012 book, Consider the Fork. British food writer and historian Bee Wilson traces the history of the fork, knife, and various other cooking and eating implements while discussing the unexpected impacts they’ve had on culture and anatomy.
Wilson says that the fork first appeared in Italy in the Middle Ages, but it didn’t catch on right away and even met with ridicule in some quarters. In early colonial America, for instance, forks were few and far between.
But eventually, table manners—and tableware—won out. By the late 1700s, most Europeans were using utensils at the dining table. It was around this time that the modern overbite began to spread in the jaws of Western Europeans. It started out as an upper-class phenomenon, but the middle classes soon joined in, adopting flatware use in the 1800s.
By the early 1900s, when stainless steel flatware became widely available, the edge-to-edge bite had all but disappeared.
[ A Closing Limerick ]
Outside of his professional work, Brace had a rather unusual hobby: He wrote limericks and poems, and he even wrote one about the overbite and dentists—not to worry, no mention of orthodontics here:
Now dentists still put up a fight
Against the thought that it might
Just be everyday use
That served to produce
The norm of the edge-to-edge bite.
But the source of our dentists’ confusion
Is just a Platonic illusion:
Knives and forks are the cause
Of the shape of our jaws
In their post-industrial occlusion.