Fluoride is a mineral present in varying concentrations in drinking water. It can prevent cavities by strengthening tooth enamel and reducing acid levels within the mouth. In Britain, fluoride is artificially added to about 10% of the water supply where natural levels are low. Some view this as a form of mass medication by the government and in conflict with an individual’s rights.

This pro-fluoridation poster carried the message: 'Fluoride in water halves tooth decay in children'. It was produced by the Health Education Council of England between 1970 and 1980.