September went out hot in East Tennessee. Caleb didn’t mind; he parked his lawn chair in a shallow pool of shade, clipped a small fan to its arm, lit a cigarette, and settled back to wait. It would be more than 12 hours before the free medical clinic opened its doors. Caleb had read about the clinic online, and that it was best to get there early. Hundreds of people were expected to show up.

Caleb had driven up from Georgia to get a cracked tooth pulled. He’s a lean, hard-looking man with a scar running vertically down from his lower lip, the result of a getting bitten by a dog. His teeth are yellowed, many of them dark brown at the gum line. A few years ago, Caleb paid more than $2,000 to have three teeth extracted by a professional, a price that he considered ridiculous. He works odd jobs but wanted me to know that he isn’t poor: He earns enough to own his house and car. “But there’s nothing in the back pocket,” he explained. Since then he’s resorted to pulling teeth on his own, with a pair of hog-ring pliers that he modified for the job. One time he messed up and crushed an aching tooth, leaving a jagged stump embedded in his jaw; he went after that with a chisel and a hammer. He saved a neighbor $300 recently, he claimed, by pulling a tooth for him. “You know what that cost him? Two and a half shots of Wild Turkey 101.”

On the ground beside Caleb sat Michael Sumers, a fellow Georgian with a long neck and wide, darting eyes. Sumers, who never saw a dentist as a child, hoped to get his remaining 14 teeth pulled. He’s only 46 years old. His mouth has hurt him almost constantly for the last five years, but he hasn’t been able to afford any help. Sumers lives on his disability check, and after paying $700 a month in rent, he doesn’t have much left. “I can’t eat steak without my teeth breaking,” he admitted.

Chicken is what broke one of Jessica Taylor’s teeth. Another two were broken by her ex-husband’s fist, when he hit her in the mouth during a fight. I found Taylor sitting on the ground, her back to a tree, a pizza box beside her. “Now I’m here,” she said, explaining why she’d come to the clinic, “and he’s in hell.”

Over on the far side of the lot, a group of women sat around a small barbecue grill, smoking cigarettes and flipping burgers: Beverly, April, Darlene, and Donna, a woman with a thin face and gray hair scraped back into a ponytail. All of them hoped to get their teeth worked on the following morning when the clinic opened. Beverly smiled, showing me how her two front teeth overlapped. Her parents divorced when she was little, Beverly told me, “and forgot which one was supposed to take care of it.” April, her sister, read about the clinic on Facebook and had been the first to pull into the parking lot that morning. At 9 am, when the clinic staff arrived to set up rows of dental chairs, April was there in a pink T-shirt, waiting on the sidewalk.

Of the countless ways in which poverty eats at the body, one of the most visible, and painful, is in our mouths. Teeth betray age, but also wealth, if they’re pearly and straight, or the emptiness of our pockets, if they’re missing, broken, rotted out. The American health-care system treats routine dental care as a luxury available only to those with the means to pay for it, making it vastly more difficult for millions of Americans to take care of their teeth. And the consequences can be far more profound than just negative effects on one’s appearance. In fact, they can be deadly.

Wealthy Americans spend billions of dollars per year, collectively, to improve their smiles. Meanwhile, about a third of all people living in the United States struggle to pay for even basic dental care. The most common chronic illness in school-age children is tooth decay. Nearly a quarter of low-income children have decaying teeth, well above the national average; black and Hispanic children also experience higher rates of untreated decay. Neither Medicaid nor Medicare is required to cover dental procedures for adults, so coverage varies by state, and both the very poor and the elderly are often left to pay out of pocket. (Tennessee provides no dental coverage to anyone over 21.) In those states where Medicaid does cover dental care, benefits are limited. Even middle-class Americans can’t always afford necessary care, as private insurance often will not cover expensive procedures. Dental coverage improved modestly during the Obama administration, through an expansion of Medicaid and the state Children’s Health Insurance Program under the Affordable Care Act, but access remains patchy and wholly inadequate.

The situation is made more difficult by the dearth of dentists in low-income communities. Less than half of the country’s dentists will treat Medicaid patients. As one dentist tells journalist Mary Otto in her 2017 book Teeth, while his colleagues “once exclusively focused upon fillings and extractions,” they “are nowadays considered providers of beauty.” Offering cosmetic procedures in wealthy cities and suburbs is far more lucrative than treating people in rural areas and poor neighborhoods—whitening alone is an $11-billion-a-year industry. The result is a geographic imbalance, with dentists clustered around the money. Nearly 55 million people live in areas officially considered to have a shortage of dental-care providers. At the pediatric dental clinic at the University of Illinois at Chicago, there’s a two-year waiting list for children who need dental surgery that requires anesthesia.

All of this explains why Caleb and a few hundred other people slept in a parking lot overnight—in their cars, in tents, or out on the ground—and then gathered in the early-morning dark, waiting for the pop-up clinic to open its doors. Held at a sports arena outside Chattanooga, the clinic is one of dozens operated each year by the nonprofit organization Remote Area Medical.

Appalachia is RAM’s home territory, but the group now runs weekend clinics in medically underserved areas across the United States, from California and Texas to Florida and New York, providing basic medical, dental, and vision care—as well as veterinary services, occasionally—fully free of charge. Dozens of doctors and dentists from across the country volunteer their services.

The group’s founder, Stan Brock, was there to open the doors at 6 am. Brock is a tan, trim man of 81 with a clipped English accent; he is also a former wildlife-television star. (A quick search turns up photos of Brock holding a lion cub, a snake fatter than his arm, and a harpy eagle named Jezebel.)

The idea for RAM came about after Brock found himself badly injured in a horseback-riding accident in a part of Guyana that was weeks away—on foot—from the nearest doctor. Initially, his intent was to fly doctors and medical supplies into remote regions of the world’s poorest countries. Brock got his pilot’s license and a small plane, and started flying medical missions into Haiti, Mexico, Guatemala, Venezuela, and Brazil. He founded RAM in 1985; a few years later, the mayor of Sneedville in northern Tennessee read about the group’s work in a newspaper. The local hospital had closed and the only dentist had left town, so the mayor asked Brock for help. Brock put a dental chair in the back of a pickup truck and drove to Sneedville, where more than 50 people lined up to have their teeth worked on. Ninety percent of RAM’s operations are now in the United States.

Little else has changed about the nature of Brock’s work in the two and a half decades since the Sneedville clinic, despite swings of the political pendulum and the passage of numerous health-care reform packages. When I asked Brock about common ailments among the thousands of people who attend RAM clinics each year, he said, “I can tell you that without any hesitation—it’s the same everywhere we go. They’re all there to see the dentist. They’re all there to see the eye doctor. They’re not there to see the medical doctor.” The health-care system treats the eyes and teeth as being distinct from the rest of the body—no matter that an infection that starts in the mouth can move quickly into the bloodstream and then throughout the body. Unlike many other acute physical problems, a cracked tooth or the gradual blurring of vision cannot be fixed in an emergency room. Nevertheless, more than 2 million people show up in the nation’s emergency rooms with dental pain each year, though hospitals can usually do little besides prescribe antibiotics and painkillers.

By the time the sky lightened, nearly 200 people had been ushered into the arena. Outside, the line still wrapped around the building. A woman at the back clutched a ticket numbered 631. Her teeth had been hurting her for a year and a half, but there was no guarantee she’d be seen. Inside, volunteers checked the patients in at rows of folding tables. Dental patients were sent to wait in the bleachers, which filled up quickly.

One by one, the people in the bleachers were summoned to a chair overseen by Dr. Joseph Gambacorta, a dean at the School of Dental Medicine at the State University of New York at Buffalo. Gambacorta peered into their mouths to determine whether they needed fillings, a cleaning, or—as was most often the case—extractions. Thirty-six-year-old Jennifer Beard from Dayton, Tennessee, sat uneasily in the chair, her mouth open. She’d already lost all but eight of her teeth. “What do I need to do? I haven’t been to the dentist in a long time,” she admitted in an apologetic tone. “My mom and dad died, and I lost my job.” It took Gambacorta about 10 seconds to assess the damage: “I hate to tell you this, but you need them all out.”

Preventing tooth decay doesn’t necessarily require a lot of money: Toothbrushes and floss don’t cost very much, Gambacorta pointed out. But it does require constant attention, and neglect is serious. One dental student who has volunteered at several RAM clinics told me about a man who arrived with a mouthful of rotting teeth; asked how often he brushed them, he replied, “Well, doc, I don’t.” Diet and habits like smoking also hasten decay. But all these risk factors are amplified by limited access to professional care. When routine care is unaffordable and decay goes untreated, minor problems can become critical. What starts out as a toothache can become an infection in the jawbone, which can then spread to the bloodstream. In one now-famous case initially reported by Mary Otto, a 12-year-old Maryland boy named Deamonte Driver died from an abscessed tooth that would have cost $80 to pull. Driver’s family had lost their Medicaid coverage, and his mother was preoccupied with trying to find a dentist for his brother, who had six rotted teeth. Driver died when the bacteria from his tooth spread to his brain—and after more than $200,000 in surgeries and six weeks in the hospital.

“Six, eight, 10, 15, 16, and two,” Gambacorta said briskly to an assistant with a clipboard, naming the teeth that had to be extracted from the head of a fidgety 30-year-old who’d last seen a dentist nearly a decade ago, when he was in Navy boot camp. Gambacorta took a second look. “Are you sure you don’t want the bottom ones out, too?” he asked. “Put 18, 19, 31, and 32 on the list, too.”

While some patients’ teeth were so decayed that Gambacorta had no choice but to recommend their removal, he hesitates to turn people into “dental cripples” unnecessarily. “Everyone’s eager to get them all out, but they don’t know what that means for after,” he told me. People assume that having dentures is easier than dealing with their rotted teeth, particularly if they’ve been in pain. But dentures come with their own complications, including the fact that people who use them tend to eat softer, less nutritious foods.

On the main floor of the arena, behind a wall of green curtains, stood four parallel rows of dental chairs—50 in all. I found April, still wearing her pink shirt, waiting in chair 22, her gums already numbed. Caleb was in chair 13; he was quiet and nervous, with little of the nonchalance he’d projected the previous afternoon while describing his pliers. Later on, I found him smoking a cigarette in the parking lot, a new gap where his top left tooth had been. “It’s embarrassing,” he said of the gap. Still, he was grateful. He was getting free eyeglasses, too; he hadn’t realized how badly he needed them.

Donna grinned at me from chair 25 as a third-year dental student prepared to pull four of her teeth. The first three came out easily, in a matter of minutes. But the fourth was stuck. It took the oral surgeon who was overseeing things a few swings of his right elbow, as if he were flapping a wing, to yank it free. Donna whimpered in pain, but a few minutes later, her mouth stuffed with gauze, she gave me a thumbs-up. The incessant ache she’d lived with for so long had already started to fade.

Over the course of two days, more than 800 people received care from RAM. Sheila Barrow, a pretty woman of 55 with dimples and long blond hair, said it was the fourth RAM clinic she’d attended. This time, she was there to have one tooth filled and another pulled. Barrow has health insurance through Tennessee’s Medicaid program, but no dental or vision coverage. She worked for UPS, but after four knee surgeries, she’s now dependent on disability benefits. “They’ve been a lifesaver,” she said of the free clinics. “I don’t know what I’d do without them.”

And yet it was clear that free clinics like RAM’s barely paper over the yawning dental-care gap. On Saturday afternoon, I found Michael Sumers in the parking lot, waiting for a ride home. All of his top teeth were gone. He’d gotten four pulled, not the 14 he was hoping for—there wasn’t enough time. Up in the bleachers, Gambacorta and another volunteer had discussed how to triage patients as it became clear that the need was greater than the number of dentists. Treating everyone in line meant that some people would have to choose between getting a tooth pulled or another one filled.

It should be unnecessary to say that a system that requires people to spend the night in a parking lot to see a dentist, or to pull their own teeth with pliers, or that leaves an infected tooth to kill a child, is grotesquely broken. Yet there is no urgency for reform in Washington, particularly with the party in power more inclined toward cutting health benefits. Part of the fault belongs with dentists’ associations, which have fought proposals for a national health-care system as well as smaller-scale reforms, like giving hygienists more autonomy to provide preventive care in public schools. The fault also rests with the policy-makers who have ignored dental care entirely when debating overhauls to the health-insurance system. Vermont Senator Bernie Sanders and Maryland Representative Elijah Cummings have repeatedly introduced legislation to expand dental coverage through Medicare, Medicaid, the Affordable Care Act, and the Department of Veterans Affairs; the latest version, introduced in 2015, never received a committee vote in either chamber.

Unless something changes in Washington, Brock predicted, “Remote Area Medical will be holding these events from now until kingdom come—instead of being where we should be, which is the Third World.”