Trends in dental caries in 12- and 13-year-old schoolchildren from Florianópolis between 1971 and 2009

Aim: To estimate the prevalence and severity of dental caries in schoolchildren from the city of Florianópolis, SC, Brazil, in 2009 and to compare these results with data from previous studies carried out in the same institution since 1971.
Methods: All 145 12- and 13-year-old schoolchildren enrolled in a public school were eligible for the study. Dental caries was assessed with the DMFS/DMFT indexes, the significant caries index (SiC) and their 95% confidence intervals (CI 95%).
Results: The response rate was 68.2%. The DMFT ranged from 9.2 in 1971 to 0.78 in 2009, although different diagnostic criteria were adopted to estimate these counts. The prevalence of dental caries declined from 98.0% (CI 95% 96.0-100.0) in 1971 to 43.5% (CI 95% 33.7-53.4) in 2009. There was a reduction of 47% in the mean SiC index between 2002 and 2009, i.e. from 3.4 (CI 95% 3.0-3.8) to 1.8 (CI 95% 1.5-2.1). The mean DMFS index was 2.0, and it was composed of an average of 1.8 and 0.2 decayed and filled surfaces, respectively.
Conclusions: Even though different diagnostic criteria were adopted during the study period, an effective decline in the prevalence and severity of dental caries in adolescents was observed throughout 38 years of monitoring.