Fluoride is necessary to prevent tooth decay. It converts hydroxyapatite, present naturally in tooth enamel, into fluorapatite, which protects teeth from breakdown by lactic acid-producing bacteria.

Fluoride must be obtained by some means to prevent decay and keep teeth healthy.

Water fluoridation

Fluoride is present naturally in drinking water; the accepted level to reduce tooth decay is 1mg/litre.

But levels are not this high in many areas of the UK and water fluoridation schemes operate in some regions, including parts of the West Midlands, the North-East, the East Midlands, Eastern England, the North-West and Yorkshire and Humber.