This post is the beginning of a twenty-part series titled “Evolution Behind Your Smile.” Across these essays, I explore how our teeth, jaws, and oral biology tell the deeper story of human evolution—one fossil, one molar at a time.
As a practicing dentist with a background in molecular biology, I’ve always felt that the dental chair is more than just a place for treatment. It’s also a lens into our species’ past. From vestigial molars to microbial arms races, the mouth holds evidence of the same evolutionary forces that shaped hands, hearts, and hemispheres.
This series doesn’t aim to romanticize biology, nor to overcomplicate dentistry. Rather, it asks a simple question: why are our bodies the way they are—especially when they seem poorly designed? The answers are rarely intuitive, but almost always revealing.
And there may be no better place to start than the infamous third molars: our wisdom teeth. They erupt late, hurt often, and rarely fit. But instead of asking why they’re such a nuisance, let’s ask the deeper question—why do they exist at all? Or better yet: why are they disappearing?
Dr. Daniel Lieberman’s work on craniofacial evolution is central to this topic. Read: The Evolution of the Human Head”
If you’ve ever had your wisdom teeth removed—or even just endured the swelling and discomfort of an impacted molar—you’ve probably wondered: why do we even have these teeth? Third molars, commonly called wisdom teeth, feel more like evolutionary leftovers than useful tools. In modern dentistry, we treat them more like ticking time bombs than anatomical assets. But from an evolutionary perspective, these teeth are a fascinating case study in how human biology often lags behind human culture.
Evolution doesn’t work like a designer with a clear blueprint. It functions more like a tinkerer—adapting, repurposing, and occasionally leaving outdated parts behind. Wisdom teeth are precisely that: parts that once had a clear purpose but now struggle to fit into our altered physiology. Our ancestors had larger jaws, coarse diets, and needed robust chewing surfaces. In that environment, three molars per quadrant made perfect sense. Today, our diets are soft, our jaws smaller, and our lifestyles fundamentally changed. Yet, the developmental instructions for these teeth are still written into our genetic code.
The discrepancy between our shrinking jaws and our persistent molar blueprint causes a widespread clinical issue: impaction. A significant portion of the population lacks the room to accommodate third molars, leading to painful swelling, infections like pericoronitis, cyst formation, and resorption of adjacent teeth. And yet, these molars continue to erupt—or attempt to—with evolutionary stubbornness.
This mismatch isn’t just anatomical—it’s cultural. The tools we invented, the cooking methods we developed, and the diets we shifted toward have all reduced our masticatory needs. Anthropologists have shown that as early humans began cooking with fire, they no longer needed powerful jaws to tear raw flesh or crush fibrous plants. Over thousands of years, this led to gradual craniofacial reduction. But here’s the catch: our genetics didn’t adapt at the same pace. The genes responsible for forming molars—like PAX9 and MSX1 play a key role in molar formation. Source: NIH NCBI—still produce the same set of instructions.
Yet, evolution isn’t static. We’re seeing emerging signs that humans are actively evolving away from wisdom teeth. A growing number of people—particularly in East Asian populations—are congenitally missing one or more third molars. In some groups, that number reaches 40%. These aren’t surgical removals, but genuine developmental absences. What’s more, the absence often runs in families, following patterns of Mendelian inheritance. This is microevolution in real time—subtle shifts across generations in response to changing environments and needs.
Beyond genes, there’s another layer: how we grow. The field of epigenetics shows us that environmental factors—like diet and breathing patterns—affect jaw development. In modern societies, children consume soft, processed foods that require minimal chewing. They also spend less time outdoors, which affects posture and craniofacial growth through airway development. All these variables contribute to underdeveloped jaws, which in turn means less space for third molars. It’s not just your DNA; it’s also your childhood lunchbox.
In the dental clinic, this plays out visually on panoramic x-rays. As a clinician, I routinely see patients with partially formed third molars, horizontally impacted roots, or follicular cysts. Some have one or two missing altogether, while others have all four—each fighting for non-existent space. The variation is wide, but the direction is clear: wisdom teeth are disappearing, but not without friction.
Interestingly, not all mammals face this problem. Other primates, such as chimpanzees, have enough space in their jaws to accommodate third molars without issue. Their diets still require intensive mastication, and their maxillofacial structures support full dental arches. Our evolutionary detour—through tools, agriculture, fire, and technology—freed us from those demands, but left us with a hangover: too many teeth in too little space.
There’s also a cultural lens to wisdom teeth. In some societies, their eruption is seen as a rite of passage—hence the name “wisdom” teeth, as they typically emerge in young adulthood. But today, they symbolize something else: the body’s inertia against its own progress. We’ve adapted so rapidly in lifestyle that biology is struggling to keep pace.
This brings us to the practical question: should we remove wisdom teeth by default? Clinically, the answer is nuanced. If the third molars are asymptomatic, fully erupted, and hygienically accessible, there’s no urgent need for extraction. However, most cases are not so cooperative. Impaction rates remain high, and the risks of retaining nonfunctional or partially erupted third molars often outweigh the benefits. Evolution may be phasing them out, but for now, dentistry has to step in where natural selection is lagging.
So, why are wisdom teeth disappearing? Because they’ve outlived their usefulness. Because the environment that shaped them no longer exists. Because our jaws evolved faster than our genome could rewrite itself. And because in the long arc of evolutionary history, unnecessary features don’t vanish overnight—they fade, unevenly, across generations.
When I extract a third molar, I’m not just removing a tooth. I’m witnessing a tiny chapter in a grand evolutionary story—a story of dietary shifts, cranial adaptation, and the slow, irregular march of biological change. Wisdom teeth are not just a clinical nuisance. They are fossils in motion. Their disappearance isn’t just inevitable—it’s already happening.
✍️ Written by Dr. Seong-Ik Hwang
DDS · MSc in Medical Molecular Biology (KAIST)
Dr. Yoon is a practicing dentist based in Sejong City, South Korea. With a background in molecular biology and a passion for evolutionary science, he brings a unique interdisciplinary perspective to clinical dentistry. He founded Goldeners.com to archive scientifically-grounded insights on biology, dentistry, and human evolution.
📍 About the Author | 📬 Contact: info@goldeners.com
