A study of 8 years' domestic salt fluoridation for prevention of caries.

The author reports on an 8-year study with 250 mg F/kg domestic salt fluoridation. During this period the dmft index in the 2-6 years age range decreased by 41%, the DMFT index in the 7-11 year age range decreased by 58%, and in the 12-14 year age range decreased by 36%. The proportion of cariesfree children also improved significantly, from 23% to 60%, from 4.8% to 41%, and from 2.7% to 8.4%, respectively. Urinary fluoride tests performed showed that with the concentration used, enough fluoride could not be ingested to reduce caries to the level anticipated with water fluoridation, but even so the caries reduction was significant. Experiments are now continuing with 200 mg F/kg and 350 mg F/kg domestic salt mixtures.