Baby teeth are more than a childhood souvenir.
They can reveal a lot about a person's physical and mental health during childhood, scientists say.
Researchers are continuing to work hard to unlock the mysteries embedded in those baby teeth.
One of them is psychiatric epidemiologist Erin Dunn, who calls herself a real-life tooth fairy.
"I am the science tooth fairy. I am a scientist who collects and studies teeth," says Dunn, a researcher with Massachusetts General Hospital.
She believes baby teeth hold important memories of childhood. Etched in the enamel are echoes of the past.
"We think they are fossilized records of people's early life experiences," Dunn said.
"Baby teeth essentially provide a snapshot of exposure to toxic metals during pregnancy and the first year of life," said Jill Johnston, Ph.D. with USC's Keck School of Medicine.
USC researchers examined the baby teeth of children living in communities near the former Exide battery recycling plant in Vernon. The teeth revealed evidence of lead exposure.
"This contamination can get inside people's bodies." she said.
Scientists take the baby teeth and slice them looking for changes in width and color.
Certain patterns can reveal evidence of stress.
Dunn and her team are recruiting women who were pregnant during the 2013 Boston Marathon bombing. They want to see if their moms' stress showed up in their children's teeth.
Eventually, the goal is to use teeth as a screening tool to determine if children could use mental health support.
"If we can be able to better identify kids early who've experienced these early life stressors, we can then more quickly connect them to interventions," Dunn said.
Johnston said this new field of research can also be used to recognize communities overburdened by not just pollution, but stress and a lack of resources.
"In those cases, we may be seeing worse health outcomes and that can really help identify neighborhoods where interventions and resources are most important," Johnston said.