After being coated on a target tooth’s surface, it extracts calcium and phosphate ions from saliva to encourage new growth of minerals. These minerals then merge with the existing tooth, effectively allowing it to regrow lost enamel. The gel could also be used to cover dentine, the bony material beneath the enamel that can be exposed due to enamel degradation, leading to infections. Lab experiments showed that a thin, protective layer formed within just weeks of applying the gel to extracted human molar teeth. “The growth actually happens within a week,” University of Nottingham biomedical engineering professor Alvaro Mata told New Scientist.