Teeth Hold a Record of Life Events
According to an article in Scientific Reports by Cerrito and colleagues,1 life stresses can produce histologic changes in cementum. The team reached this conclusion after investigating teeth recovered from cadavers of individuals between 25 and 69 years old. The subjects were chosen because their medical and life histories were available for study. The authors determined that numerous events are recorded in cemental tissues, including pregnancy, lactation, menopause, systemic illnesses, incarceration, and even moving from the country to the city.
Unlike enamel and dentin, human cementum can respond to physiologic changes over the lifetime of the tooth. The researchers postulate this is possible because cementoblasts found in the apical region of the tooth are multipolar and have a higher secretion rate potential than those in the cervical region. These cementoblasts can produce incremental bands that are visible in both cellular (apical) and acellular (cervical) cementum. While this finding could give rise to studies of human lifestyles and development, the authors note their conclusions are based on a small sample and need to be verified through additional research.
Another study on a similar topic by Miller et al2 was recently published in Proceedings of the National Academy of Sciences. In this work, the investigators were able to trace the health and activity of a mastodon by evaluating the mineral deposits in its tusks. Unlike human teeth, mastodon (as well as modern elephant) tusks continue to grow throughout the animals’ lifetime. By measuring the amount of strontium present in the tusks, this subject’s migratory habits could be determined. This was possible because previous studies had identified the mineral’s prevalence throughout the mastodon’s migratory range.
They were also able to measure the amount of water molecules trapped in the tusks at different times of its life, which allowed them to estimate rainfall amounts. The researchers used this data to study these events in the years when this animal was between 11 and 16, and 31 and 34 — spans that were chosen to minimize the amount of material needed for analysis. Previous studies had shown that mastodon life cycles were similar to that of modern elephants. The findings suggest this mastodon migrated over a large area of what is now Illinois, Indiana, Ohio and Michigan. They also found this bull had suffered from malnutrition early in life, and later died after having its skull impaled by another bull’s tusk — likely in a battle over mating privileges.
The authors of both papers feel that evaluation of dentition can reveal important information about an animal’s life and its environment. This can be used to improve our understanding of the consequences of environmental changes and their effects on the human and animal kingdoms.
Thomas G. Wilson Jr., DDS
Editor in Chief
- Cerrito P, Baile SE, Hu B, Bromage TG. Parturitions, menopause and other physiological stressors are recorded in dental cementum microstructure. Sci Rep. 2020;10:5381.
- Miller JH, Fisher DC, Crowley BE, Secord R, Konomi BA. Male mastodon landscape use changed with maturation (late Pleistocene, North America). Proc Natl Acad Sci. 2022;119:e2118329119.
From Decisions in Dentistry. August 2022;8(8)4.