A 7-year-old boy, whose name has not been made public, had more than 500 tiny "denticles" removed from a tumor in his mouth last month.P. Ravikumar / Reuters

The tooth fairy is working overtime this week. On Thursday, a group of oral surgeons in Chennai, India, released a case report describing an already rare phenomenon at its most extreme. A young boy, just 7 years old, was being treated for jaw pain last month at Saveetha Dental Hospital near the country’s southeastern coast when clinicians realized he had 547 teeth—the most ever counted in one person.

The boy, who appears in photos shared by the hospital but remains unnamed, only ever had a standard child’s set of 20 or so teeth visible to the naked eye. (The average adult has 32.) His parents first noticed a small lump pushing up against his right cheek when their son was 3; when they took the toddler to the doctor, however, he refused to sit still for any exams, so it remained untreated. By the time the boy’s parents brought him to the dental hospital, the lump was nearly the size of a golf ball. Last month, doctors surgically removed the growth and sliced it open. They found a sac with 526 tiny teeth inside, like a fleshy, overstuffed coin purse.

The sac was an odontoma, a noncancerous growth that forms in some children during the years-long process of tooth development. Baby teeth, and then later on secondary teeth, grow from clusters of stem cells deep in the jaw, pushing up from below and erupting through the gums once fully formed. As the secondary set grows and baby teeth begin to fall out, the jaw stretches to accommodate its new, larger tenants. With all this growth and movement, the stem-cell hubs can sometimes forget what they were supposed to be doing and spin out of control, producing tooth-building materials.

Such aberrations have been reported as far back as 1839, but their cause remains a mystery. By many accounts, they’re the most common type of jaw tumor. They’re generally found in people under 20, but they grow slowly—at least as far as jaw lumps with menacing names are concerned—so they’re often not detected before a child turns 10.

By far the most unique feature of an odontoma is what lies within. The tumors contain buildups of the same biological materials that make up teeth; in some cases, like that of the young boy in Chennai, they’re arranged into a collection of many small teeth that are structurally identical to those outside the tumor. In other words, much like a cystic pimple hijacks the production of skin cells and collects them into an ever-expanding, juicy pustule, an odontoma slurps up the calcifying components of our chompers as the body builds them.

Given the biological specifics of odontomas, there’s an argument to be made that the miniature teeth pulled from the Chennai boy’s mouth can’t be considered teeth in the classical sense. “They're not full-size teeth: Some people call them microdonts, or denticles, or toothlets,” says Sidney Eisig, the chief of dental service at NewYork–Presbyterian Hospital and a professor at Columbia University’s dental school. Compared with normal teeth, “these denticles have the same cells. They have enamel, they have dentin, they have maybe some cementum. It has the structures of the tooth.” The only real difference is that denticles don’t grow through your gums and help you chew food.

In a photo shared by the Chennai team, the 526 denticles look like they could be a collection of deep-sea gems or scraps of geodes harvested from volcanic rock—a swirling array of smooth beads laid out with elegant precision on a turquoise mat. The majority of them are just a few millimeters long, which explains how they all fit inside the mouth of a child who had more than one tooth for each week he’d been alive. The total tally decimated the previous record for the number of teeth found in a single odontoma: a mere 232, freed from the jaw of a Mumbai teenager in 2014.

Dentists arrange the 526 extra teeth found in the seven-year-old's mouth into a spiral pattern.
P. Ravikumar / Reuters

It’s rare to find more than a handful of denticles in one odontoma, and cases with more than 30 or so are generally considered impressive enough to make their way into medical journals and the news. “It’s not unusual to have a tumor that size, but it might only have five of these toothlike structures,” says Amr Moursi, a spokesperson for the American Academy of Pediatric Dentistry and the chair of the pediatric department at New York University College of Dentistry. “They’re just larger.” Pratibha Ramani, the head of oral and maxillofacial pathology at Saveetha Dental, said via email that counting and examining the teeth took four and a half hours. From there, it was another week and a half, long after the little boy was home and healing, before pathologists were done examining the denticles one by one to confirm that each had the chemical hallmarks of a tooth.

Given the murkiness that surrounds the origins of even the most modest odontoma, identifying the physiological root of the super-tumor would be a huge breakthrough. Ramani’s team has suggested that aside from simple genetic predilection or mutation, radiation exposure could have played a role in the cyst’s formation. She told The New Indian Express that she recently began research “to see if radiation from mobile phone towers is a factor in such conditions.”

But half a dozen other experts I asked about this theory enthusiastically called it, in Eisig’s words, “total BS.” The American Cancer Society and other national health organizations clearly state that the maximum amount of radiation a person can pick up from cell towers is still thousands of times smaller than any amount that could affect health. There’s little evidence that even cellphones themselves could pose a threat. As Eisig put it, “We all carry them around in our pockets—if they were cancer-causing, boy, we’d be in the middle of one big epidemic right now.”

And even if the city of Chennai had been founded within the core of a massive, faltering nuclear reactor, a tidy odontoma bears none of the hallmark features of documented tumors caused by radiation exposure. “The fact that these are benign, well-controlled, well-encapsulated lesions doesn't suggest that there are the types of major mutations going on that you might think could be caused by radiation,” Moursi says.

Instead, say Eisig and Moursi, the best explanation for the staggeringly high number of “toothlets” is a simple one: time. The odontoma had been growing freely in the boy’s jaw for at least four years, filling up gradually with more and more of the small teeth. Had doctors removed it when his parents first brought him in for treatment at age 3, the contents of the cyst would likely have been unremarkable. The surgical team acknowledged that the case is a clear example of the kind of medical predicament that can occur when families lack access to or don’t make adequate use of health care. “Earlier, things like not as many dentists, lack of education, poverty meant that there was not as much awareness,” one of the doctors who helped remove the odontoma told CNN. “These problems are still there.”

And even among the privileged few with access to adequate care, Eisig says, some people just really, really hate going to the dentist. “We see that people just don’t want to go in and see a clinician to get care,” he says. “And they end up with these big, big tumors. It’s just amazing what people will live with.”

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.