As we all know, the older we become, the weaker our teeth because enamel can not regenerate like bones and skin. Still, we know little about how exactly this process happened, and that's why a group of scientists from the University of Washington researched this topic, examining human teeth on an atomic level.
So, how it works?
Scientists observed the fundamental structure unit of tooth enamel – mineral structures that are ten thousand times smaller than the width of human hair.
They obtained two samples – teeth from 22 and 56-year-old participants to examine them closely. Scientists "divided" the tooth into three parts: core, shell, and space between them. In the older sample, researchers found a much larger concentration of fluoride – the mineral usually consumed via water and toothpaste – in all layers, but the highest concentrations were observed in the shell region.
However, what is more important is the discovered difference in size and form of mineral nanocrystals of human enamel. As it turned out, nanocrystals in young samples are much larger and located less tightly in the shell structure with small gaps between them. (highlighted on the image)
The old sample, in turn, has more contrast, and smaller nanocrystals with higher intergranular thickness. This phenomenon may be caused by the process of organic content disruption in tooth enamel – as protein is gone, crystals become smaller, and the intergranular phase replaces some of their volume over time. Additionally, scientists confirmed that fluoride in old teeth enhances mineral dissolution resistance in tooth enamel.
Why it's important?
Researching tooth enamel on atomic scales will help medicine find some therapies that can help repair tooth enamel and increase enamel density. Also, scientists contribute to the most discussable topic in the modern dental community – the importance of fluoride consumption – providing evidence that this substance plays a crucial role in the mineral structure of human enamel.
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