“Like the rings of a tree, teeth contain growth lines that may reveal clues about childhood experiences,” an article on The Harvard Gazette (THG) reads.

“Dendrochronology — the study of geological data present in the age rings of trees — allows us to see emission levels, particulate pollution, moisture levels, drought conditions, forest fires, and indeed pandemics told like stories in the wood… This data not only tells us about what the climatic conditions were, but is also useful to predict what they will be,” Akhila Vijayaraghavan, a molecular biologist who runs an urban hydroponic farm focused on agri-tech innovations, had written in an article for The Swaddle last August. Turns out, baby teeth, too, hold a repository of information that can be used to predict potential mental health disorders.

Being exposed to physical stressors, like poor nutrition or disease, impacts the formation of dental enamel — resulting in “stress lines,” which are pronounced growth lines within teeth much like the age rings of trees. “Just as the thickness of tree growth rings can vary based on the climate surrounding the tree as it forms, tooth growth lines can also vary based on the environment and experiences a child has in utero and shortly thereafter, the time when teeth are forming,” THG explained, adding that “thicker stress lines are thought to indicate more stressful life conditions.”

Basically, “teeth create a permanent record of different kinds of life experiences,” Erin C. Dunn, a social and psychiatric epidemiologist, who co-authored the study, summed up in her statement.

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Published in JAMA Network Open, the present study analyzed baby teeth belonging to 70 children, whose teeth fell out of their mouths between the ages of 5 to 7. The researchers found the neonatal line (NNL) in baby teeth to be an indicator of whether an infant’s mother experienced high levels of psychological stress during pregnancy, or could access social support in the early period following birth. The more stress an individual experienced — either before or after being born — the thicker their NNLs were, and vice versa.

Research suggests that childhood adversity is responsible for almost one-third of all mental health disorders. However, at present, there aren’t many effective tools available to measure one’s exposure to childhood adversity — leave alone the degree of such exposure. Dunn notes asking people — or their parents — about their difficult childhood experiences isn’t foolproof because it relies primarily on human memory. Moreover, not everyone chooses to open about painful memories.

That’s precisely why the results of this study are promising. “[T]he findings could lead to the development of a much-needed tool for identifying children who have been exposed to early-life adversity, which is a risk factor for psychological problems,” THG notes.

Identification can pave the path for early intervention, the researchers hope. “We can connect those kids to interventions… so we can prevent the onset of mental health disorders, and do that as early on in the lifespan as we possibly can,” Dunn concluded.