I’m staring at my skull. Or, more accurately, my jaw: lower left molars glow in one black-and-white snapshot, upper left molars in another, teeth foreign yet familiar in their eerie greenish cast. The side view, the front view. The gem of the collection: the full-mouth panorama, taken only once every five years. It’s hard to avoid, projected in stunning accuracy on a computer screen a few feet from my face.

Teeth tell a story, we learned in anthropology last semester. Wear and tear, breakage, size, texture. The skulls lined the lab tables, resting on foam, labeled with index cards that stated sex, species. We ran our fingers over the blond-bleached jaws of hominins long dead, felt the bulge of healed fractures, the tiny irregularities in color. While everyone made notes on the presence or absence of sagittal crests, I sat with the skulls, brushing my fingertips over the old, old teeth.

Now, sitting here in the dentist’s chair, I try to make out my story from the glowing teeth on the screen. They seem fairly ordinary. Better, if you count the orthodonture. Worse, if you count the missing tooth. They seem to hang in space, broad knobs sliding to curving roots. Around the outside, the delicate trace of a ghostly jaw.

Someday, if my skull sits on a lab table, its index card will read, Female, Homo sapiens. There it will sit, on white foam, a trace of a life. Manmade dental sealants on top and bottom molars; missing left lower canine; one cavity, filled.

***

The dentist’s office, from the outside, resembles a shell-colored strip mall. Step inside the glass doors, and you’re in the jungle: a long corridor of palm trees, ferns, leafy warm plants breathing in moist, heavy air. The intensity of the green swallows your footfalls across the cement indoor sidewalk that leads to your dentist, your orthodontist, your anesthesiologist, rheumatologist, gynecologist, oncologist, physical therapist, therapist. A professional park, it’s called. The plants, I assume, are there to dilute the -ology. This building bursts with human beings’ knowledge of human beings: our brains, lungs, reproductive organs, cancers, bones. We know ourselves so well. We have named every one of our teeth.

“Just take a swish of this mouthwash, hon,” says Dot.

She is busily arranging the sharp dental implements on their tray, asking me about my family, asking me about school. I’ve come to this dentist’s office since I was three years old. Nothing about it surprises me any more, not even the ten-foot-tall toothbrush statue in the lobby.

My family’s fine, I assure her.

A friend of mine told me last year that he hasn’t been to the dentist in five years. Your teeth look fine, I said. He just laughed. No health insurance.

I try to remind myself of my privilege as I lie here on Dr. Isaacson’s blue leather chair. I know I’m lucky to lie here every six months, to have grown accustomed to the bright plastic-covered light hovering above my head, to the red panels of the Mondrian print that hangs in the hallway outside. There was no dental care for most of human history, I tell myself. I visualize the skulls in the anthropology lab, dirty and broken, the chipped and missing teeth. I’m so lucky to have been born in this century, lucky to receive expensive care, lucky to be able, miraculously, to see every tooth’s flaw in sharp black and white on a screen. But I do not know my luck the way I know what comes next — the small pinpricks of pain from the sharp dental tools that Dot, the hygienist, holds gracefully in one manicured hand. That is a different knowledge. I still flinch.

For years, I dreaded my cleaning appointments, just as I dreaded vaccines, green leafy vegetables, therapists, gym class, and other features of the privileged world. Most of all, I dreaded cavities.

For years I brushed my teeth every day, moving the toothbrush in small, exact circles, as the hygienist instructed, to prevent the buildup of evil plaque. And for years I waited nervously at the conclusion of my dental check-up, as Dr. Isaacson leaned back on his blue-leather stool, sharp instrument in hand. His lips were always slightly wet, as if he was concentrating on something deep in his brain that made him forget to dry them. There was a lot of information deep in his brain. He knew everything about teeth. Everything there was to know. Otherwise, I reasoned, he wouldn’t be a dentist.

“Did you find anything?” I would ask.

“No cavities,” he would smile, and nod me out of the hygienist’s room to get my sticker at the front desk.

They found one when I was eight. A cavity. They found it, they filled it. I don’t even remember which tooth it was on. But it’s there, some mark of imperfection, of the frightening permanence of bone.

 ***

As a child, during cleanings, all I could think about was the buzzing of brush against tooth, the pluck of floss, the taste of blood, the light scrapes of metal against enamel. Now, I daydream. As Dot prepares the electric toothbrush, I close my eyes. Where to go, where to go? My mind ricochets a while, and I find myself in anthropology lab again, staring at skulls lined on a table; some anthropology lab far in the future, and the skull on the table is mine.

Strange, the anthropology student is bound to remark. Missing lower left canine.

“Did you find anything?” the teaching fellow asks.

“Well, there’s evidence of orthodonture,” the student replies.

What evidence, I don’t know. Tiny spots, perhaps, where the metal buds clung to incisor and premolar, holding tight the clear plastic wires that drew the teeth together, month after month, in some inverted tug of war. I got braces after the surgery, to fill the space where my missing tooth would have been. But he can’t know that.

“Good,” says the TF. “Anything else?”

“Well, the left lower canine is simply gone.”

“Gone?”

“It’s not there. Look.” He holds up the skull so that the TF can see.

“Interesting,” says the TF. She moves on.

***

“Did you find anything?” I asked, five years ago, at the end of my check-up.

“I’m more concerned with what I can’t find,” said Dr. Isaacson. “Your left lower canine is simply gone.”

“Gone?”

“It’s not there. Look.” He points to the space between my incisor and premolar on the whitish print of the X-ray.

“Where is it?”

It was there last time I had X-rays. I was positive. We were looking at two sets of images. In the older print, the canine in question hibernated snugly under my baby tooth. Now, the baby tooth was gone, and nothing slept beneath it. Just dark space.

“I don’t know,” said Dr. Isaacson.

***

“What happened to her tooth?” the student asks. He’s beckoned the TF over again.

It’s evening, and the TF wants section to be over so she can go home and feed her terrier. “I don’t know,” she says. “Genetic, maybe.”

“How do we know?”

“We can’t.”

***

I can hear the buzzing as Dot scoops up some of the grainy mint toothpaste. Long ago, there was a selection of flavors — cherry, strawberry, bubblegum. For adults, there’s only mint. The rapidly rotating brush tickles my tongue.

“All set,” she says, replacing the brush in its holder. “Time to floss. Do you floss regularly?”

I don’t floss as much as I should, but “regularly” is pretty vague. I say, “Yes.”

“And you wear your retainer?”

I nod.

“That’s great. I can tell,” she approves. “Your teeth are still so aligned. It’s amazing, they covered that whole thing up so well. That crazy thing with your canine, I mean.” She readjusts her facemask, sawing delicately between my teeth. She speaks about Dr. Nicosizis, down the hall. He was the orthodontist in charge of realigning my teeth after the surgery. “Who would have guessed?”

Who would have guessed, that it was there the whole time?

The X-ray from five years ago is on that screen, too. The panorama, taken only every five years. It’s the one where you have to stand in the hallway with your teeth biting around a plastic grip as the camera — or whatever it is that takes X-rays — zooms around your head.

I don’t know how X-rays work, I realize, just as I don’t know the names for all of my teeth, or how to fit braces, or if one of the skulls on the lab table belonged to an ancestor of mine. I don’t know much about anthropology, or any -ology. I don’t know where I will be in two years. I don’t know why my lower left canine turned downward, buried itself in my chin, or why it lay there for two years, encased in bone, until we spotted it on my panorama, five years ago, a tiny white dot in the milky smoke of my X-rayed jaw. It took a wrong turn.

Dot is finishing the flossing. “Dr. Isaacson will be in shortly,” she smiles, and takes my file out of the room. She leans back in to add that I can read People magazine if I want.

I’m okay, I say. I stare at the ceiling instead.

Dr. Isaacson comes in. “Hello,” he says in his wet-lipped way. He palpitates my lymph nodes, clinks the metal instruments around my mouth. He always jokes about my missing tooth. “Who would have guessed?” He feels the scar tissue from the surgery that removed it. “Anything hurt?”

I shake my head. The surgical wounds have long healed. I have the tooth, small and bloodied, in a Ziploc bag somewhere at home.

Dr. Isaacson wishes me luck this semester. I thank him. He floats out.

Lying here, I can almost make out the small wrinkles of consternation on the face of the anthropology student. He puzzles over the missing tooth. Perhaps his name is Mark. I wonder how my skull came to rest on his lab table. He wonders how my skull came to be rest on his lab table. Traces of orthodonture. High cheekbones. Small chin. Female, Homo sapiens. He wonders about the color of my eyes.

“And it looks like you’re due for some X-rays,” says Dot.

***

Perhaps later, he will find the cavity. Turning the skull in the yellow light of the lab, as footsteps in the hall fade across linoleum. The TF will be clicking off the lab lamps, one by one. Female, Homo sapiens. One missing tooth, one cavity. He will know which tooth it was on; he will feel the filling, the tiny bump against his thumbnail as his fingers trace the old, old teeth. Didn’t brush every night, did she? But only one cavity; she learned her lesson. And there — on her chin, below the missing canine, the slightest trace of a scar.