Dental caries-reducing effects of a milk fluoridation project in Bulgaria

The aim of the present study was to investigate the effects of a community-based milk fluoridation project on dental caries.

Fluoridated milk was provided to about one-half of kindergarten and other schoolchildren in Asenovgrad, a town in the southern part of Bulgaria. The estimated daily milk consumption was 200 ml containing 1 mg of fluoride (approximately 5 ppm F). Cross-sectional samples of 6 1/2-year-olds in Asenovgrad and Panaguriche (a nearby town selected as the reference community) were examined at the start of the study in 1988 and after three years. Additional cross-sectional samples of 7 1/2-year-olds in Asenovgrad who were and were not drinking fluoridated milk were examined at baseline and at three years to provided an internal control group. Samples of 6 1/2 and 8 1/2-year-olds from Asenovgrad and Karlovo were examined in 1993 to provide for five-year follow-up comparisons.

In 6 1/2-year-old children who had consumed fluoridated milk for three years, there was a decrease in the mean dmft per child of 40 percent and in the mean DMFT of 89 percent compared to children examined at baseline. Children in Asenovgrad who were 4 1/2 years old at the start of the study and had been drinking fluoridated milk for three years had on average 44 percent fewer dmft and 83 percent fewer DMFT at 7 1/2 years of age than those not drinking fluoridated milk. After five years the dmft index was 40 percent less and the DMFT index 79 percent less in those children who had participated in the full five years of the program compared to the control group.

Results seem to confirm the caries-reducing effects of milk fluoridation found in previous studies. Unexpected large caries reductions obtained in this nonexperimental study, however, probably cannot be attributed to the fluoridation of milk alone. The mere introduction of the project might have led to other changes affecting dental caries, such as improved oral hygiene and better dietary habits.