Teeth: Lines of Evidence

Look closely. Closer than you’d ever care to.

Not at a smile, not at a grin, not at that dashing white flash in a toothpaste ad, but deep into the enamel, into the microscopic, slow-growing, mineral-bound memory palace of a tooth.

Teeth are not just bones in your mouth. They are diaries, passport stamps, autopsy reports. They are the hardback biography of a life, abridged, annotated, and forever open to those who know how to read it.

I was heartened to see the BBC’s documentary “Humans”, in which explorer, paleoanthropologist and evolutionary biologist Ella Al-Shamahi raises the issue of tracing our history through fine lines on our teeth.

The Concept of Perikymata

Each tooth is engraved with perikymata, those infinitesimal horizontal lines that ripple across the surface like the grooves on an ancient vinyl, only instead of playing Bowie, they tell you how many weeks someone’s been alive.

Each line: a week. Each pause: a hardship. Like tree rings, but with more cavities and far less poetic metaphor. You can count them, line by line, and arrive not just at how long someone lived, but how difficult it was to do so.

This is archaeology’s dirty little secret: it’s not the skull, not the femur, not even the sacred skull cup of mythology that tells us most about the human story.

It’s the teeth. Always the teeth. Because teeth, unlike hearts, don’t lie. They endure. They sit in the earth like mute time capsules, pristine in death, broadcasting the granular truth of ancient lives long after flesh and folly have dissolved.

Reaching Maturity

Consider this: Homo sapiens takes significantly longer to reach sexual maturity than our flatter-headed, brow-ridged cousins, the Homo erectus. Why? Because we needed more time to grow into our brains. Bigger brains are hungry, needy things. They require decades of schooling, storytelling, mimicking, failing.

Childhood is the price evolution charged for intellect. And teeth, patient stenographers that they are, recorded every payment. The longer we stayed children, the more time we had to learn how to be human. That, in the end, is the evolutionary leap that made the rest of our ambitions – language, war, inventions and Instagram posts, even possible.

Through teeth, archaeologists have reconstructed entire lives. Wear patterns alone can reveal diet: Stone Age bread would turn your molars into gravel. Agriculture introduced sugars that brought about the first cavities; the early price of civilisation, one sugar beet at a time.

Isotope analysis can tell whether someone dined on fish or fowl, goat or grain. Decay, gum disease, enamel defects are all postcodes on the map of ancient nutrition.

Some teeth, curiously, have been intentionally filed, dyed, even inlaid with precious stones, rituals and aesthetics we might call madness now, though it was no stranger than Botox and braces. Some people used their teeth like pliers, bottle openers, or sewing machines; wear patterns revealing daily labour that never reached the history books.

And then there are the dead whose teeth whisper stories of more than hunger and hygiene. They tell of health and horror. Infected gums, abscesses, and lost molars reveal diseases and diets gone wrong.

Dental calculus, basically fossilised plaque, preserves the DNA of ancient microbiomes, parasites, and even the herbs and medicines they chewed. One might say plaque is the unsung hero of forensic archaeology: a gunky, glorious treasure trove.

Migration

And let’s not forget migration. The chemical composition of tooth enamel is a geological signature, a fossilised postcard from childhood. Because enamel forms in youth and never changes, you can tell exactly where someone grew up, even if they died half a continent away. It’s the ultimate biometric. Your teeth don’t just betray your secrets, they carry your accent in calcium.

Take Lindow Man, for instance. Pulled from the peat of Cheshire in 1984, he was part body, part time machine. His teeth said he was about 25 when he died, just enough time to have grown wise but not cynical. No evidence of cavities, no signs of childhood malnutrition. He ate well, likely meat, which means he was probably privileged by Iron Age standards.

His last meal? A gruel of barley and wheat. No meat. Possibly a ritual fast. Possibly his last supper before a sacrificial death.

His smile was a social clue, a health chart, a religious artifact.

Even Neanderthals got in on the act. They used toothpicks. Evidence of rudimentary dentistry, flossing with twigs, perhaps. And in their dental calculus? Traces of medicinal herbs. Early medicine, straight from the mouth.

In the end, the humble tooth gives us more than the jawbone of an ass or the poet’s grin. It gives us life, unvarnished, unerased, and unforgiving. From childhood trauma to migratory dreams, from what we chewed to what we cherished, our teeth are the last to leave the party and the first to spill the beans.

Next time you smile in the mirror, know this: you’re not looking at decoration. You’re looking at data. Evolution’s diary, written in enamel, and read by those brave enough to peer past the gloss.

Fast forward to today. If tooth decay were a celebrity, it would be the Kardashian of kids’ diseases, ubiquitous, gaudy, and tragically misunderstood. Five times more common than asthma, tooth rot sends British children to hospital more than any other ailment, making molars a national emergency.

Fluoride flows, dentists drill, sugar is scorned, yet cavities cavort undeterred. Now the plot thickens: even kale-munching, floss-wielding cherubs are losing teeth.

Enter prenatal villains: maternal diets, C-sections, microbiomes and fluoride itself. The truth is, we’ve been analysing the mouth while the mystery starts in the womb. Oral health, it turns out, begins long before the toothbrush arrives.

But that’s all for another day.