What happens to our teeth as we age? New details have emerged

Our teeth, the essential guardians of our oral health, are constantly subjected to the demands of chewing and grinding.

Their outer layer, enamel, is an exceptionally hard substance and the most durable material in the human body. While it provides vital protection, enamel lacks the ability to regenerate or self-repair, unlike other tissues in the body.

Unfortunately, this enamel isn’t immune to the ravages of time. A team of researchers has recently explored how enamel morphs with age.

The ultimate goal of the research is to devise ways to maintain the strength and vigor of our teeth for as long as possible.

Teeth contain more fluoride with age

The study, led by researchers at the University of Washington and the Pacific Northwest National Laboratory, scrutinized the atomic makeup of enamel samples taken from the teeth of a 22-year-old and a 56-year-old.

Interestingly, the older tooth harbored increased levels of ion fluoride – an element often added to our drinking water and toothpaste as a protective measure for enamel.

The researchers investigated how fluoride integrates into enamel as we journey through life.

Where teeth cracks begin

Study lead author Jack Grimm is a UW doctoral student in materials science and engineering and a doctoral intern at PNNL.

“We know that teeth get more brittle as people age, especially near the very outer surface, which is where cracks start. There are a number of factors behind this – one of which is the composition of the mineral content,” said Grimm.

“We’re interested in understanding exactly how the mineral content is changing. And if you want to see that, you have to look at the scale of atoms.”

Microscopic structure of enamel

Enamel is composed mostly of minerals arranged in microscopic structures ten thousand times tinier than the width of a human hair, which makes it a challenge to study.

Earlier studies were conducted on a larger scale – about a tenth of the size of a human hair – which made it impossible to discern the relative distribution of minerals and organic portions in enamel’s crystalline structure.

To investigate the microscopic structure of enamel more deeply, Grimm collaborated with Arun Devaraj, a materials scientist at the Pacific Northwest National Laboratory (PNNL). Together, they used a sophisticated technique called “atom probe tomography.”

This cutting-edge method enabled them to create a 3D map of each atom within a sample, revealing differences in element compositions across three key areas: the nanocrystal core, the shell coating the core, and the space between the shells.

The role of fluoride as teeth age

The team found that samples from the older tooth had enhanced fluoride levels, predominantly in the shell regions.

Study co-author Cameron Renteria is a postdoctoral researcher in oral health sciences at the University of Washington.

“We are getting exposed to fluoride through our toothpaste and drinking water, and no one has been able to track that in an actual tooth at this scale,” said Renteria. “Is that fluoride actually being incorporated over time? Now we’re starting to be able to paint that picture.”

According to the researchers, the strength of their work lies in its interdisciplinary nature. By combining the expertise of different scientific fields, they were able to uncover fascinating insights.

Going forward, the team plans to investigate how the protein composition of enamel evolves over time.

How enamel changes over time

Enamel, though resilient, undergoes subtle but impactful transformations as we age. The study revealed that the mineral composition in older enamel is more compact but also more brittle.

Over the years, cycles of demineralization and remineralization, influenced by diet and exposure to fluoride, lead to structural shifts.

Interestingly, these processes primarily affect the outermost shell of enamel’s nanocrystals, where increased fluoride levels were most evident in older teeth. This outer layer, while stronger against acid attacks, becomes more prone to cracks due to its rigid nature.

Preserving the strength of teeth

Such changes highlight the delicate balance between strengthening enamel and preserving its flexibility – a challenge that future dental treatments aim to address.

Dentistry offers a clear recommendation: fluoride and fluoridated products are effective in preventing tooth decay. But when it comes to how aging influences teeth overall, it seems the jury is still out.

The research highlights a key consideration as we grow older – our teeth may become more brittle, requiring us to chew with greater care.

The full study was published in the journal Communications Materials.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–