Fluoride Additives in Toothpaste

       Fluoride ions also help maintain the strength of the enamel. Fluorides are present in toothpastes largely in the form of stannous fluoride (SnF₂, Fluoristan), sodium monofluorophosphate (Na₂PO₃F), and sodium fluoride (NaF).

• replacing some of the hydroxyl groups in the enamel's hydroxyapatite, converting it to a harder mineral, fluoroapatite, which is more resistant to erosion by acids, and    

• suppressing the bacteria's ability to generate acids.

       Although not our principal protection against tooth decay, the surfactants of toothpaste formulations do not effectively remove loose debris from the mouth and also gives us the sense of cleanliness. Almost all dentifrices contain a bit of saccharin and some flavoring or fragrance to leave us with a sense of sweetness and freshness after brushing. The components of a typical toothpaste appear in Table 2.

Table 2   Composition of a Typical Dentifrice

Ingredient	Formula	Weight (%)	Function
Water	H2O	37	Solvent and filler.
Glycerol	CH2OH-CHOH-CH2OH	32	Humectant, retains moisture.
Dibasic calcium phosphate	CaHPO4	27	Abrasive.
Sodium N-lauroyl sarcosinate	(See Fig. 20.4)	2	Surfactant and inhibitor of enzymes that produce decay.
Carrageenan	(A carbohydrate of seaweed)	1	Thickening agent and stabilizer.
Fluorides and other additives		1	Enamel hardener; sweeteners and preservatives.

Next: Surfactants