Canadian researchers have found that a person’s first permanent molars carry a lifelong record of health information dating back to the womb, storing vital information that can connect maternal health to a child’s health, even hundreds of years later.
Their findings are published in the American Journal of Physical Anthropology.
Dentin, the material under the enamel that makes up the bulk of a tooth, forms in microscopic layers that compare to the rings of a tree. Adequate formation of those layers is dependent on Vitamin D. Dark streaks develop in periods when the body is deprived of the critical nutrient, usually due to lack of sunlight.
Researchers at McMaster University, led by anthropologist Megan Brickley, had previously established that such microscopic defects remain in place and can be read later, in the same way a tree trunk can show years of good and poor growth. Because teeth do not decay as rapidly as flesh and bone, they can retain such information for hundreds of years post-mortem.
Combined with other data, patterns in dentin can create rich banks of knowledge about past conditions, including the health impacts of living in low-light environments.
Now the same team has established the value of such records, which begin during the original formation of teeth in the fetal stage, for reflecting the health of the mother during pregnancy. All of the body’s primary or ‘baby’ teeth, which start forming in utero, are lost in childhood.
The first permanent molars—which emerge around age six—also start forming in utero and stay in the mouth throughout one’s adult life, where they retain a record of Vitamin D intake dating back to the mother’s pregnancy.
That record provides a critical intergenerational link that can offer valuable clues connecting maternal health to the eventual fate of a child.
“We’ve been able to set out really clear evidence that there is part of the first permanent molar that records what happened in the life of the mother,” Brickley said.
“This is a tool that people can use. It can be used in current health research, and in bio-archaeological research.”