Acids from foods, drinks or sugars weaken the enamel surface, exposing a dull yellow layer and making it more susceptible to further damage. While any toothpaste containing fluoride helps prevent this erosion, Pronamel Active Shield, has a proven formula that ACTIVELY REINFORCES weakened enamel and protect teeth from future acid erosion. It works by locking in minerals into the surface of the enamel. It helps repair and rebuild microdamage in the enamel surface. Helping protect enamel against future acid wear.