Cracked.com Whitening toothpaste, by and large, is regular toothpaste with grit in it. It can be anything from aluminum oxide, which is the main ingredient in chalk used for billiards, to calcium carbonate, the basic ingredient of many antacids. Basically, if it's gritty, it'll scrub shit off your teeth. They could use sand in whitening toothpaste and get the same effect. Blandaðu bara smá sandi í tannkremið þitt.