Rodent teeth inspire advances in human dentistry
Atomic-scale imaging and nanoscale spectroscopy, combined with 3D tomography, scanning and optical microscopy, have led to a paradigm shift in the understanding of the coloration generation in rodent incisors. Findings that could improve human dentistry.
Teeth are natural composites of optimally arranged simple inorganic and organic components. Among these, dental enamel is the most mineralized and the hardest tissue in our body. Fully formed, highly crystalline enamel is composed of elongated calcium-containing hydroxyapatite crystals (96 wt%), with the rest being organic material and water.
Continuously growing rodent incisors exhibit natural adaptations through structural and chemical optimization. They form masterpieces of architecture with exceptional physical properties when compared to human teeth. These elongated, rootless structures are characterized by their distinctive orange-brown color, where hard enamel selectively covers the labial side of the incisors, transforming them into a self-sharpening device. Rodent incisors serve as a model system for understanding the development of human teeth.
In the recent paper published in ACS Nano, Srot et al. tracked the biological processes and architectural design of continuously growing rodent incisors from a variety of rodent species inhabiting different habitats. The infusion of iron-containing ferrihydrite-like material into the interstices between the elongated hydroxyapatite crystals in the outer enamel, along with the formation of the transition zone (TZ) and surface layer (SL), represents essential enhancement of the outer iron-rich enamel (Fe-EN). Although the filled pockets account for less than 2% of its volume, they are believed to play a critical role in improving mechanical properties and enhanced resistance to acid attack. Most importantly, Fe-EN is not the primary source of the characteristic color observed on the surface of rodent incisors, as was previously thought. Instead, the typical orange-brown coloration results predominantly from the above lying SL (and TZ). The functional significance of acid-resistant Fe-EN and the understanding of the coloration generation have far-reaching implications for human health, restorative dentistry, and the development of an entirely new class of dental biomaterials with enhanced properties.
Their work has been highlighted by the American Chemical Society (ACS) in their press release, and has attracted the attention of international and German media (scinexx.de das wissensmagazin, Focus online), with a total of 15 news stories so far (https://acs.altmetric.com/details/162579688/news).