Davie Researchers Uncover Secrets to Lifelong Tooth Enamel Durability

Davie Researchers Uncover Secrets to Lifelong Tooth Enamel Durability

Davie residents, amid the sunny vibes of Broward County's horse country, might be surprised to learn that the very enamel protecting their teeth, despite daily wear and tear, is designed to last a lifetime. Unlike skin or bone, which can repair themselves, tooth enamel cannot regenerate. Yet, it endures the incredible stress of mealtime, extreme pH changes, and temperature fluctuations.

Researchers have long pondered how enamel remains functional and intact for decades. As Professor Pupa Gilbert from the University of Wisconsin–Madison, one of the lead authors of a recent study, put it, “How does it prevent catastrophic failure?”

The secrets of enamel’s resilience have now been unveiled thanks to a collaborative effort involving Prof. Gilbert and researchers from the Massachusetts Institute of Technology (MIT) in Cambridge and the University of Pittsburgh, PA. Their findings were published in the journal Nature Communications.

The team took a detailed look at the structure of enamel, which is composed of enamel rods made of hydroxyapatite crystals. These long, thin rods are approximately 50 nanometers wide and 10 micrometers long. To visualize these minute structures, the scientists utilized a cutting-edge imaging technology called polarization-dependent imaging contrast (PIC) mapping, a technique designed by Prof. Gilbert herself.

Before PIC mapping, studying enamel with such precision was impossible. Prof. Gilbert explained, “You can measure and visualize, in color, the orientation of individual nanocrystals and see many millions of them at once.” This method makes the complex architecture of biominerals like enamel visible to the naked eye.

Upon examining the enamel structure, researchers discovered intricate patterns. “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,” Gilbert noted. This observation led to the crucial question: “Is this a useful observation?”

To determine if the varying crystal alignment impacts how enamel withstands stress, the team enlisted the help of Prof. Markus Buehler of MIT. Using a computer model, they simulated the forces experienced by hydroxyapatite crystals during chewing. The model showed that when two blocks of crystals met at an angle, smaller angles were more effective at deflecting cracks.

Co-author Cayla Stifler further investigated by measuring the angles between adjacent crystals using the original PIC mapping data. After analyzing millions of data points, Stifler found that a 1-degree misorientation was the most common, with a maximum of 30 degrees. This aligned with the simulation, confirming that smaller angles help deflect cracks.

Prof. Gilbert concluded, “Now we know that cracks are deflected at the nanoscale and, thus, can’t propagate very far. That’s the reason our teeth can last a lifetime without being replaced.” This breakthrough offers a deeper understanding of the remarkable durability of our teeth, ensuring Davie residents can continue to enjoy their meals at local spots like the Bergeron Rodeo Grounds without concern for their enamel’s longevity.