While our bodies have remarkable abilities to heal wounds and mend broken bones, tooth enamel lacks the capacity for self-regeneration, enduring the harsh conditions of the oral cavity with every meal.
The daily stresses of chewing, combined with drastic shifts in pH and temperature, constantly challenge enamel’s resilience. Remarkably, the enamel we develop in childhood remains with us for life, prompting researchers to explore its secrets for longevity.
In a recent study published in Nature Communications, scientists, led by Prof. Pupa Gilbert from the University of Wisconsin–Madison, along with researchers from the Massachusetts Institute of Technology (MIT) and the University of Pittsburgh, delved into the structure of enamel.
Enamel consists of enamel rods made of hydroxyapatite crystals, each about 50 nanometers wide and 10 micrometers long. With advanced imaging technology called polarization-dependent imaging contrast (PIC) mapping, developed by Prof. Gilbert, researchers visualized the alignment of individual crystals in enamel with unprecedented detail.
Their observations revealed a gradual change in crystal orientations within enamel rods, challenging the notion of a single orientation. Utilizing computer simulations of chewing forces, the team found that smaller angles of crystal misorientation, averaging 1 degree with a maximum of 30 degrees, were more effective at deflecting cracks.
These findings shed light on how enamel’s intricate structure contributes to its resilience, offering insights into potential strategies for enhancing dental health and longevity.
With this newfound understanding, it becomes evident that cracks are diverted at the nanoscale, preventing them from spreading extensively. This phenomenon elucidates why our teeth can endure throughout our lives without requiring replacement.
Revised from Prof. Pupa Gilbert
