Dental caries prevalence and mean dmf-t among schoolchildren between 1971 to 1997, Brazil

Abstract

INTRODUCTION: Cross-sectional surveys carried out in Brazil during the last decade have showed a significant decrease in both prevalence and severity of dental caries. However, the validity of these studies is questioned. Different methodologies as well as diagnosis criteria were used. Thus, a study was carried out with the purpose of comparing the prevalence and severity of caries among schoolchildren aged 12 and 13 years in a region of Brazil. METHODS: Two cross-sectional surveys were carried out. All 12 and 13 year old children enrolled in a primary school were examined by a single dentist in 1971 (n=202) and 1997 (n=175), following the same protocol. The original criteria for the diagnosis of caries proposed by Klein and Palmer in 1937 were used both in 1971 and 1997. A total of 202 and 175 children were examined in 1971 and 1997 respectively. RESULTS: The response rate was 100%. Intra-examiner agreement was very high. Kappa test was performed on a tooth by tooth basis and all values were above 0.86. The prevalence of caries was 98% and 93.7% in 1971 and 1997 respectively. Comparison of the severity of caries experience expressed as changes in the mean DMF-T scores showed a reduction from 9.2 to 6.2 between 1971 and 1997 in the study group. CONCLUSIONS: There was a significant reduction in dental caries prevalence and severity between 1971 to 1997 in the study population. The observed reduction of caries was not a statistical artifact as the same methodology and diagnostic criteria were applied in both cross-sectional surveys.