Teeth constitute a permanent and faithful biological archive of the entirety of the individual’s life, from tooth formation to death, according to researchers at New York University (NYU) whose work provide new evidence of the impact that events such as reproduction and imprisonment have on an organism.
“Our results make clear that the skeleton is not a static organ but rather a dynamic one,” said Paola Cerrito, a doctoral candidate in NYU’s Department of Anthropology and College of Dentistry and lead author of the study.
The researchers focused on cementum, the dental tissue that covers the tooth’s root. It begins to form annual layers like the rings in a tree from the time the tooth surfaces in the mouth.
“The discovery that intimate details of a person’s life are recorded in this little-studied tissue promises to bring cementum straight into the center of many current debates concerning the evolution of human life history,” said Timothy Bromage, PhD, a professor at NYU’s College of Dentistry.
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.
“The cementum’s microstructure, visible only through microscopic examination, can reveal the underlying organization of the fibers and particles that make up the material of this part of the tooth,” said Cerrito.
The researchers examined nearly 50 human teeth age 25 to 69 drawn from a skeletal collection with known medical history and lifestyle data such as age, illnesses, and movement such as from urban to rural environments. Much of this information was obtained from the subjects’ next of kin.
Next, the researchers 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. It continuously adjusts and responds to physiological processes,” said Cerrito.
“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,” said Cerrito.
The study, “Parturitions, Menopause and Other Physiological Stressors are Recorded in Dental Cementum Microstructure,” was published by Scientific Reports.