The effect of fluoride consumption and social class on dental caries in 8-year-old children.

School dental service data indicate that whilst Melbourne eight-year-old children had worse dental health than similar children in the Geelong area in 1979, the situation in 1985 was the reverse. In order to investigate this, and determine the effects of socio-economic level (SEL), residential history, and fluoride history on dental caries status, 208 eight-year-old children in the Melbourne area and 209 eight-year-old children in the Geelong area were examined for dental caries. A questionnaire was administered to gain details of subjects' exposure to water and supplement fluorides. The SEL of the subjects' school was used in place of individual SEL. A high proportion (46 per cent) of Geelong subjects used a fluoride supplement at some stage, but few continued this for most of their life. Residential history was important, with 2.4 per cent of the Melbourne subjects living most of their life in a nonfluoridated area and 3.4 per cent of Geelong subjects living most of their life in a fluoridated area. There was a significant difference between the dmft in Melbourne and Geelong when only children who had lived all their life in the city in which they were examined and did not use a fluoride supplement were included. A large part of this difference is attributed to water fluoridation in Melbourne. A substantial number of children would benefit from fluoridation of the reticulated water supply in Geelong, particularly those in the lower social classes.