Stannous fluoride (SnF2;also called tin fluoride) was first formulated
successfully into a toothpaste to deliver an anti-cavity benefit in the 1950s. Fluoride
is highly reactive, and the challenge was finding an abrasive system that had low
enough reactivity with fluoride to maintain fluoride being available.
Sodium fluoride (NaF) is a fluoride salt commonly used in toothpaste
and oral rinses. Sodium fluoride delivers a highly reactive fluoride ion; therefore,
formulating it with a compatible abrasive is critically important for achieving the anti-cavity
benefit. In the early 1980s, silica abrasives that were compatible with sodium fluoride
became available and allowed toothpaste with stannous fluoride to be reformulated with the more stable sodium fluoride.
Sodium monofluorophosphate (SMFP) was introduced in 1968. Unlike sodium fluoride, SMFP is not an ionic fluoride salt, but rather a covalently bound fluoridated compound that requires enzymatic activation by a salivary enzyme (alkaline phosphatase) to release bioavailable fluoride. Because of this lower reactivity, SMFP is compatible with more abrasives than other fluoride sources