Enamel, the protective layer on the outside of the teeth, is the hardest biological tissue in the human body; however, too much sugar and poor dental hygiene can cause plaque to accumulate in the mouth, and the accompanying bacteria release acids that can destroy it. When tooth enamel is damaged, it does not grow back: this results in the formation of those cavities-caries-that need to be filled by a dentist.
But now, researchers from China’s Zhejiang and Xiamen Universities have discovered a way to regrow human tooth enamel, a technique they hope will one day be used by dentists to repair teeth. They essentially made use of two minerals, calcium and phosphorus, which are two key components of natural enamel, and incorporated it into a special gel.
As a first test, the Chinese team layered the gel on a surface quite similar to dental enamel, consisting of crystalline hydroxyapatite, and the result was as hoped: calcium phosphate particles in the gel in the form of small bunches (clusters) fused with the material.
The next step involved the use of laboratory-available human teeth to which the researchers intentionally damaged the enamel with acid and then covered them with the gel. The teeth were then placed in containers that mimicked the physicochemical conditions found inside the human mouth for 48 hours. The results of this second experiment were also surprisingly positive: in this short period, the substance had formed an albeit very thin layer of coating similar to natural enamel, with similar strength and resistance characteristics. Even in microscopic analysis, the researchers could see that the coating had a crystal structure similar to the enamel that covers our teeth. Although the layer was very thin, the authors explained that it can be thickened simply by applying the gel several times.
Clearly, the road to application is still a long one, involving testing in animal models and eventually in humans, but its potential is great and perhaps could revolutionize the way we treat tooth decay, potentially eliminating the need for fillings.
Source:
Shao C, Jin B, et al. Repair of tooth enamel by a biomimetic mineralization frontier ensuring epitaxial growth. Science Advances Aug 30, 2019: Vol. 5, no. 8, eaaw9569.
