Recently in China, a team of scientists have developed a gel that can regrow tooth enamel. Tooth enamel is the hard, outer surface layer of your teeth that serves to protect against tooth decay. Usually, teeth enamel cannot grow back once it breaks or wears away due to its complicated structure covering the surface of a tooth. It is formed biologically and can therefore cannot be self-repaired, increasing the chances of cavities. However, with the new gel it is great because it is made of the same material as enamel, consisting of calcium and phosphate ions. https://www.intelligentliving.co/scientists-develop-gel-regrow-tooth-enamel/