Our bodies possess remarkable abilities to heal and recover from injuries, with skin and bones being excellent examples of this regenerative power. However, when it comes to tooth enamel, the story is different. Unlike other tissues, tooth enamel cannot regenerate, and the oral cavity presents a challenging environment.
Each time we eat, our enamel is subjected to immense stress and exposed to drastic changes in pH and temperature. Despite these harsh conditions, the tooth enamel that forms during childhood accompanies us throughout our lives.
Researchers have long been intrigued by how enamel manages to endure and remain intact over a lifetime. In the latest study, Professor Pupa Gilbert from the University of Wisconsin–Madison and her team delve into this question, seeking to understand how enamel avoids catastrophic failure.
With collaboration from researchers at the Massachusetts Institute of Technology (MIT) in Cambridge and the University of Pittsburgh, PA, Professor Gilbert conducted an in-depth examination of enamel's structure.
Their findings have been published in the journal Nature Communications.
Enamel is composed of enamel rods, consisting of hydroxyapatite crystals. These enamel rods are remarkably slender, measuring around 50 nanometers wide and 10 micrometers long.
Utilizing cutting-edge imaging technology, the scientists successfully visualized the alignment of individual crystals within tooth enamel. This advanced technique, known as polarization-dependent imaging contrast (PIC) mapping, was developed by Prof. Gilbert.
Prior to PIC mapping, such detailed studies of enamel were unattainable. Prof. Gilbert emphasizes that this breakthrough technology allows researchers to measure and visualize, in color, the orientation of countless individual nanocrystals simultaneously, providing a remarkable insight into enamel's structural intricacies.
With the use of PIC mapping, the intricate architecture of complex biominerals, like enamel, becomes readily visible to the naked eye.
As the researchers observed the structure of enamel, they made an intriguing discovery. Instead of a single orientation in each enamel rod, they noticed a gradual change in crystal orientations between adjacent nanocrystals. Professor Gilbert explained, "By and large, we saw that there was not a single orientation in each rod, but a gradual change in crystal orientations between adjacent nanocrystals." This finding led them to question the significance of this observation and its potential implications.
