AFT Efficacy

Efficacy of FT

The anti-caries efficacy of FT is of paramount importance. The definitive proof is to show its inhibitory effect on caries in a clinical trial, involving a large sample over a 2-year period (FDI, 1999). Such a study would be expensive and difficult to carry out because of ethical and confounding factors.

A study from 2005 shows great differences between the amounts of total and free fluoride in toothpastes from different countries (v Loveren et al).

The first developed FT's (1000-1500 ppm F) were not effective against caries in clinical trials (Bibby, 1945; Muhler et al., 1955; Kyes et al., 1961). This mystery was solved by Ericsson (1961), who showed that the fluoride reacted with other components . Thus for a FT to be effective the fluoride must be free and not bound to other ingredients (abrasives).

The literature does not provide clear information at which concentrations of free available fluoride a FT can still be considered to exert anti-caries efficacy. However, since toothpaste manufacturers add fluoride to ensure anti-caries efficacy, their products should contain free available fluoride. It implies that the added, free, fluoride is not bound to other ingredients.

In sodium FT (NaF), amine fFT (NH4F) and stannous FT (SnF2), fluoride should be available in ionised form. For sodium monofluorophosphate toothpaste (SMFP - Na2FPO3), fluoride is bound to the phosphate and thus less sensitive for non compatible soluble calcium containing abrasives.
Most FT's today contain 0.10-0.15% (1000-1500 ppm) fluoride, usually in the form of sodium fluoride (NaF) or sodium monofluorophosphate (SMFP).

The establishment of a national system of regular assessing freely available fluoride in toothpaste is recommended, since this assessment does not resort under the legislation for cosmetic products.