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The tooth fairy is calling: Boston researchers seeking baby teeth for health study

The scientists are trying to find a diverse group of mothers who were pregnant near the time of the Boston Marathon bombing.

Nora Fong, 8, played jump rope with her sister Lilly, left, and friend Lila. Nora and her mother Andrea are participating in the tooth fairy study, a research project by MGH scientist Dr. Erin Dunn and her team to study children's baby teeth for signs of stress.Erin Clark/Globe Staff

Could children’s teeth tell us something about who they will become and what mental health challenges they could encounter?

Dr. Erin Dunn believes they can, envisioning a day when physicians routinely scrutinize children’s incisors or canines — after they fall out — for signs of early life trauma, experiences researchers believe may increase a person’s risk of later problems.

Such a screening, Dunn hopes, could one day become as routine as the blood tests doctors use to check a patient’s cholesterol and glucose levels, measures that indicate whether a person faces an increased risk of heart disease or diabetes.

Dr. Erin Dunn and her team are studying children's baby teeth for signs of early stress and adversity that may be a marker for who might be at risk for mental health problems in adolescence. Jessica Rinaldi/Globe Staff

“We are looking within teeth to see if the body retains a memory of what happens earlier,” said Dunn, an associate professor at Massachusetts General Hospital and the lead researcher of a study that aims to show whether baby teeth — instead of being discarded when they fall out — can be used as a reliable marker for potential future problems.

Two years ago, Dunn’s team started recruiting New England area women who were pregnant during — or had given birth one year before — the 2013 Boston Marathon bombings to test the viability of large-scale screening of trauma and baby teeth. Women do not need to have had a direct connection to the bombing or the manhunt for the suspects afterward. Study recruitment, hampered during the pandemic, has been revived and the plan is to sign up at least 250 women and their children. So far, about 200 have enrolled since 2020.


Dr. Erin Dunn holds up a bag containing an exfoliated molar. Jessica Rinaldi/Globe Staff

If her team can pinpoint a reliable correlation between stress and teeth markings, it “opens up the opportunity to use teeth as a new tool to help guide primary prevention efforts,” Dunn said. Ultimately, she hopes to identify strategies to improve resilience among children.


As baby teeth form before birth and during the first few years of life, they develop microscopic growth marks within the hard enamel surface, much as rings in a tree mark its age.

Growth marks in baby teeth typically record daily and weekly development up to about 2 years old, whereas growth lines in some secondary or permanent teeth — which Dunn also hopes to analyze going forward — record development up to age 16.

The cross-section of an exfoliated incisor baby tooth mounted to a holder for analysis at Dr. Erin Dunn’s office.Jessica Rinaldi/Globe Staff

Adverse experiences in childhood — and even adversity experienced by mothers when they are pregnant — may affect that growth process, leaving abnormal marks or stress lines that permanently record the specific day or week in development when that stress occurred.

As proof the concept could work, Dunn’s team recently published findings from a study of 70 children — born in the early 1990s — whose baby teeth, along with surveys of their mothers, had been stored in an English repository as part of a decades-long study of mothers and children.

A longitudinal thin section of a baby tooth on a slide that is used to examine the tooth under a microscope. Jessica Rinaldi/Globe Staff

They found that the teeth of children whose mothers reported a history of depression or other psychiatric problems, or who experienced anxiety or depression at 32 weeks of pregnancy, had a distinctive wider line in the enamel from the time of their birth, compared to youngsters whose mothers didn’t report such problems.

Dr. Jack Shonkoff, director of the Center on the Developing Child at Harvard University, said Dunn’s team’s early findings are promising, but a lot more research needs to be done before baby teeth could be considered a reliable screening tool.


“There is enough evidence to say it looks like there is a there there,” Shonkoff said.

Shonkoff’s center is working on an approach to use children’s saliva as a potential screening tool related to early life stress, while other researchers are focusing on blood, hair, and even stool samples from pregnant women.

“We are early in that process,” he said.

Dunn said the April 2013 Boston Marathon bombing was chosen because it gives researchers a distinct set point.

“It had a clear start and end date and it happened on a community-wide scale, affecting a large number of people,” she said.

The researchers intend to explore how the bombing, whether the mother was running in the Marathon, or watching it (even on TV), or perhaps had a loved one injured, may have affected her stress levels and the teeth of her infant or unborn child.

They are hoping for a wide range of experiences and also for diversity; so far about 90 percent of those who have volunteered are white.

Some of the women already have started sending their children’s teeth; kids start losing their baby teeth around 6 years old, so many of the babies from 2013 are continuing to lose teeth now. The researchers send children a “Science ToothFairy” book explaining the research, as well as badges for each tooth received.

In return, the team has received some treasures, along with the teeth, like the note 8-year-old Nora Fong of Newton penned to the ToothFairy in December.


“Can you please leave my tooth my mom sends it to a scientist [sic] that studies my tooth! So if you can leave my tooth it would be awesome. thank you,” read the note mailed, along with a tooth, from Nora’s mother, Andrea Fong.

Andrea Fong and her 8-year-old daughter, Nora, sat on the deck of their Newton home.Erin Clark/Globe Staff

Her brother-in-law was running the race, and when Fong — who was on a business trip in Florida —heard about explosions near the finish line, she frantically and repeatedly texted her sister, then waited for what seemed like hours before she heard he was OK.

Nora was born weeks later, in May.

”I was super emotional, pregnant, and felt like ‘What am I doing bringing a child into this world’ [when the bombs went off] and I felt super compelled to sign up,” Fong said.

“To the extent this study is able to tell if children are going to have markers of this stress, and maybe you can alleviate the stress as they get older, it would be a wonderful thing,” she said.

Two leading German researchers who study teeth from ancient civilization to glean knowledge about conditions for maternal and infant life said the Marathon bombing project is a reasonable approach for identifying signs of stress in children.

“If it turns out that psychosocial stress also has an effect on enamel formation, and it can be analyzed ... then this is one part of the story,” said Carsten Witzel, a biology scientistat the University of Hildesheim “The next one would be, does this have some sort of predictive value for future stress experiences?”


Tiffany Free, another Massachusetts woman who signed up for the study, has sent five of her sonHolden’s teeth.

“You don’t have the heart to throw them out, but you don’t necessarily need to keep them all this time,” she said. “So it was a perfect solution.”

Holden, who is now 9, was 10 months old at the time of the bombing. Free and her husband, along with Holden, had just strolled away from the finish line when the bombs went off.

Amid the terror and chaos, they walked nervously home to Cambridge, too afraid to go into the subway. When she got home, Free, a surgical technician at Massachusetts General Hospital, grabbed her work badge and headed in to help as injured patients were flooding the emergency room.

“Crowds and things like that were deeply stressful for a while afterward,” she said. But Free hasn’t seen signs that Holden, or his younger brother, are afraid of crowds, and the family has returned to watch the race since then.

Dunn, the lead researcher, is hoping to follow Holden and the other children for several years into adolescence and perhaps to also search for signs of stress from the COVID-19 pandemic in their permanent teeth, which would be forming now.

About 20 percent of children on health insurance have at least one tooth removed to make room for braces, which would provide Dunn’s team the perfect opportunity to study those teeth, too.

“Every tooth,” she said “has the potential to tell its own story.”

Kay Lazar can be reached at Follow her @GlobeKayLazar.