Teeth act as a ‘faithful archive of life’ by forming layers like tree rings that reveal intimate details of a person’s life such as when they got pregnant, fell ill or were in prison
- Material called cementum in teeth develops a new microscopic layer every year
- Lab analysis reveals it changes in shape and structure when a body is stressed
- Cementum looks visibly different at these times and reveal past details
- Scientists tell by studying the teeth what caused a change and when it happened
Human teeth act like tree rings and store intimate details about a person’s life, a study has found.
The research by American scientists found a material in teeth called cementum develops a fresh layer every year.
Studying subtle changes in its growth can provide key details such as when an individual was pregnant, seriously ill or in prison.
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Left, a look at the second molar of a 35-year-old female who had children at ages 19 and 24. Middle is a zoomed-in section of the left image. Right, the cementum, which presents two distinct darker ‘rings’ that correspond to the two reproductive events
Results show the skeleton is not a static organ but is constantly changing, according to the study’s researchers.
Researchers tested whether significant events in a person’s lifetime can have a discernible impact on the material’s formation.
It was also found key events in a person’s life can be timed using the tooth rings.
Physiologically taxing events such as pregnancy, menopause, imprisonment and systemic illness leave permanent changes in the cementum’s microstructure.
Physiologically taxing events such as pregnancy, menopause, imprisonment and systemic illness leave permanent changes in the microstructure of cementum, a material that grows a new layer every year on the tooth root (stock)
Lead study author, Paola Cerrito, a doctoral candidate at New York University (NYU), said: ‘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.
‘A tooth is not a static and dead portion of the skeleton. It continuously adjusts and responds to physiological processes.
‘Our results make clear that the skeleton is not a static organ, but rather a dynamic one.’
HOW DO TEETH ACT LIKE TREE RINGS?
Cementum is a dental tissue that covers the tooth’s root.
It grows a new layer roughly every year.
The cementum’s microstructure is visible only through microscopic examination.
Analysis can reveal the underlying organisation of the fibres and particles that make up the material of this part of the tooth.
The microscopic layers can be illuminated using a variety of laboratory methods.
Each layer has slightly different structure as the body forms i=the cementum .
When the body is under strain, the structure is very different to under normal conditions.
How the body is under strain can also be determined as well as when.
The study, published today in the journal Scientific Reports, focused on cementum, a dental tissue that covers the tooth’s root, as grows reliably.
From the moment a tooth surfaces in the mouth, it starts to form annual layers similar to a tree’s rings.
Professor Timothy Bromage, from the NYU’s College of Dentistry, said: ‘The discovery that intimate details of a person’s life are recorded in this little-studied tissue, promises to bring cementum straight into the centre of many current debates concerning the evolution of human life history.’
In the study, scientists examined nearly 50 human teeth, aged 25 to 69, drawn from a skeletal collection with known medical history and lifestyle data.
This included details such as age, illnesses, and movement, for example from urban to rural environments. Much of this information was obtained from the subjects’ next of kin.
Researchers 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.