This study analyzes the DMF and DEF indices, SiC index, and percentage of caries-free public schoolchildren in the municipality of Bilac, São Paulo State, Brazil, in 1998, 2000, 2002, and 2004. The same methodology was employed (WHO-1997) in all the surveys. Kappa test was carried out at each stage, and the minimal and maximum inter-examiner agreement values obtained were 0.86 and 0.89, respectively, while minimal intra-examiner agreement values were 0.91. DEF indices decreased slightly in the years 1998 and 2004. There was a continuous reduction in the DMF index, as well as the phenomenon of polarization at 12 years of age. The rate was 5.28 in 1998, decreasing to 4.11 in 2000, 3.47 in 2002, and 2.62 in 2004. Inversely, the proportion of caries-free 5-year-olds increased from 37.9% in 1998 to 40% in 2000 and 2002 and 45.3% in 2004. In conclusion, there has been a decrease in dental caries in 12 year-old public schoolchildren in the municipality.