The major ingredient in Crest was discovered by accident when a student left a sample in the furnace too long and when discovered, found that it made it possible to mix the ingredient with fluoride. At first it used stannous fluoride, marketed as "Fluoristan" (this was also the original brand name it was sold as. Later it changed from "Fluoristan" to "Crest with Fluoristan"). The composition of the toothpaste had been developed by Drs. Muhler, Harry Day, and William H. Nebergall at Indiana University, and was patented by Nebergall.
Procter & Gamble paid royalties from use of the patent and thus
financed a new dental research institute at the university. The
active ingredient of Crest was changed in 1981 to sodium
monofluorophosphate, or "Fluoristat". Today Crest toothpastes use
sodium fluoride, or "Dentifrice with Fluoristat". Recently
introduced Crest Pro-Health, uses stannous fluoride again and an
abrasive whitener together called "Polyfluorite".