The caries examinations at baseline and after 3 and 5 years were performed by dentists calibrated by a WHO epidemiologist. Urine monitoring was carried out regularly. After five years, mean dmft values were 52% lower in the test group children aged 6 1⁄2 years and 40% lower in the 8 1⁄2 year olds. The reductions in mean DMFT in these two age groups were 89% and 79% – statistically highly significant. After 10 years of the programme, Atanassov and colleagues recorded further significant differences in the proportion of caries-free children and in mean DMFT (1) values of the test and control groups. In some communities there is a preference for fluoridated yoghurt.