Among the hardest substances the body produces, tooth enamel is also among the most irreplaceable — once gone, no biological process brings it back. Researchers at the University of Nottingham have now developed a fluoride-free gel that does what the body cannot: it mimics the protein-guided processes of early tooth formation to regrow organized enamel crystals from minerals already present in saliva. Published in Nature Communications and moving toward commercialization within a year, this work quietly redraws the boundary between what dentistry can repair and what it must merely manage.