Social Factors Associated with the Decline in Caries in Brazilian Children between 1996 and 2010.

Dental caries levels have declined in children since the 1970s in many countries. Most of the postulated main reasons for the decline are speculative and have not been rigorously evaluated. The objective of this study was to assess the relationship between some social factors and the decline in dental caries in Brazilian 12-year-old children from 1996 to 2010. Secondary analysis of national data was performed in 27 Brazilian state capitals. A panel data regression model with fixed effects and multiple linear regression were used to verify the relationship between the explanatory and the dependent variables and also the time-trend effect. The results showed that the DMFT (decayed, missing, and filled teeth) decreased by about 3% per year, and the percentage of caries-free children increased by 4.5% per year. For DMFT and percentage caries free, the results for the panel data regression showed a significant association for the Human Development Index (HDI) in the adjusted model (p = 0.010). When the overall changes over time were compared, the Gini index had a significant association with the overall change in DMFT in the final model of the multiple regression analysis (p = 0.033). Our results indicate that the maintenance of good levels of human development, which includes better education, income, and longevity, are important factors relating to improving levels of oral health in 12-year-old Brazilian children. However, to accelerate this process in cities with the worst caries situation, income inequality should be tackled.