Sodium fluoride

The primary mode of the caries preventative action of fluoride is post-eruptive, i.e topical action. Systemic fluoride supplements are believed also to act mainly topically (i.e during ingestion, via saliva).

There are three types of effect associated with fluoride:

• The inhibiting effect on demineralisation (lowering the enamel solubility in an acid environment).
• The promotion of remineralisation of enamel during the caries process.
• A bactericidal effect upon dental plaque organisms. This results in inhibition of proliferation of dental plaque bacteria and prevents formation of the acids that cause caries.

Fluoride alone is not enough to eliminate bacterial plaque, nor as a complete treatment for caries.

Sodium fluoride toothpaste has a local, topical action on the teeth and so the route taken within the body does not apply. However, the following information has been included in case any toothpaste is accidentally ingested during treatment.

Absorption

Ingested fluride is converted to hydrofluoric acid. Peal concentrations are achieved within 30–60 minutes.

Distribution

The volume of distribution is 1 L/Kg. Fluoride ions are distributed to teeth and bones, and are not bound to plasma proteins.

Biotransformation

Ingested fluride is converted to hydrofluoric acid.

Elimination

The terminal half life is in the range 2–9 hours. Fluoride ions are excreted mainly in urine, but small amounts may also be excreted in faeces and sweat. It is not known in which form.

Non-clinical data reveal no special hazard for humans based on conventional studies of safety pharmacology, repeated dose toxicity, genotoxicity, carcinogenic potential, toxicity to reproduction and development.

After oral administration of sodium fluoride to mice, rates and rabbits, reproductive and foeto–toxic effects were observed only at high dose levels.