What is Tetrasodium Pyrophosphate & Disodium Pyrophosphate?

Tetrasodium pyrophosphate and disodium pyrophosphate are the anti-tartar ingredients in Crest Whitening Expressions. They are normal components of human body fluids, are used in many foods, and they have a GRAS (Generally Recognized as Safe) rating from the FDA. These ingredients prevent the formation of crystals that can eventually become tartar.