Since about 50 years ago showed that the decay could be controlled with the use of fluoride, many preparations have appeared that contain it. Some are for professional use and some not.

Fluoride has three very beneficial effects on teeth:

- Increases the resistance of enamel: Applying fluoride on the teeth, it reacts with calcium in them, forming calcium fluoride. In this way, the fluorine reacts with the crystals of tooth enamel (hydroxyapatite), resulting in a compound that greatly increases the resistance of enamel.

- It helps remineralisation: Fluoride contributes to the remineralization of the tooth, by encouraging entry into the structure of calcium and phosphate ions. This is because the fluoride has negative charge and attracts the calcium and phosphate whose charge is positive.

- Has antibacterial action: Fluoride has antibacterial action attacking the bacteria that colonize the tooth surface.