Teeth constitute a permanent and faithful biological archive of the entirety of the individual’s life, from tooth formation to death, a team of US researchers has found.
Their work—published in Scientific Reports—provides new evidence of the impact that events, such as reproduction and imprisonment, have on an organism.
The research focused on cementum, the dental tissue that covers the tooth’s root. It begins to form annual layers— similar to a tree’s ‘rings’—from the time the tooth surfaces in the mouth.
The study tested the hypothesis that physiologically impactful events—such as reproduction and menopause in females and incarceration and systemic illnesses in both males and females—leave permanent changes in the microstructure of cementum and that such changes can be accurately timed.
In their work, the scientists from New York University examined nearly 50 human teeth, aged 25 to 69, drawn from a skeletal collection with known medical history and lifestyle data, such as age, illnesses, and movement (e.g., from urban to rural environments). Much of this information was obtained from the subjects’ next of kin.
They then used a series of imaging techniques that illuminated cementum bands, or rings, and linked each of these bands to different life stages, revealing connections between tooth formation and other occurrences.
“A tooth is not a static and dead portion of the skeleton,” lead author Paola Cerrito said. “It continuously adjusts and responds to physiological processes.
“Just like tree rings, we can look at ‘tooth rings’—continuously growing layers of tissue on the dental root surface. These rings are a faithful archive of an individual’s physiological experiences and stressors from pregnancies and illnesses to incarcerations and menopause that all leave a distinctive permanent mark.”