One important study included in the York review looked at the dental health of 5-year olds living in electoral wards of seven fluoridated areas and seven matched non-fluoridated areas with varying degrees of social deprivation (1).

The study concluded that water fluoridation reduces tooth decay more in disadvantaged communities than in affluent communities, and that the introduction of water fluoridation schemes in areas where levels of poverty and tooth decay are high, such as Manchester, “would substantially reduce inequalities in dental health”.

Figure 1 shows the relationship between tooth decay and social deprivation in both fluoridated and non-fluoridated communities.  It demonstrates that:

• Young children (5-year olds) living in poverty generally have higher levels of tooth decay than more affluent children.

• Water fluoridation reduces the effects of social deprivation on tooth decay.

• The difference in tooth decay rates between poor and affluent children is smaller in fluoridated communities than in non-fluoridated communities.

• Where the level of deprivation is the same, children in non-fluoridated communities have more tooth decay than those in fluoridated communities.

• When two communities with national average levels of social deprivation are compared, children from the non-fluoridated one have an average of just over one additional tooth decayed compared with children from the fluoridated one.

• When two communities with 10% more than the national average level of social deprivation are compared, children from the non-fluoridated one have around two more decayed teeth than children from the fluoridated one.  In other words, the link between poverty and tooth decay is weaker in fluoridated areas than non-fluoridated areas.

1. Riley JC, Lennon MA, Ellwood RP (1999): The effect of water fluoridation and social inequalities on dental caries in 5-year old children.  International Journal of Epidemiology, 28: 300-305.​​