Title:
Trends in Socioeconomic Disparities in Oral Health in Brazil and Sweden

Abstract:
It has been suggested that new interventions, as the time goes by, may initially increase socioeconomic inequalities to decrease afterwards, the so called inverse equity hypothesis. The dynamics of trends in inequalities is not well understood yet. Our objective was to describe and explore trends in socioeconomic gaps in oral health in Brazil and Sweden. This study is a time trend analysis of cross-sectional studies designed to assess the prevalence of oral health and other population characteristics. In Sweden we have data available for the years 1968, 1974, 1981, 1991 and 2000. In Brazil data was available for 1986 and 2002. Trends in complete or partial edentulism are shown, as well as trends in no missing/good teeth. There was on average an annual decline in absolute disparities of 0.5% (95% CI= 0.1-0.8) in Brazil and 0.7% (95% CI= 0.5-0.9) in Sweden. Results concerning no missing teeth (Brazil) / teeth in good conditions (Sweden) were mixed. In Brazil the absolute and relative disparities in the prevalence of no missing teeth has increased, while in Sweden there was a statistically non significant decrease in disparities in the prevalence of those with teeth in good conditions. At least, since 1991 in Sweden and 2002 in Brazil, we found that, in the age group of 35-44, there are no significant socioeconomic disparities in edentulism either in absolute or relative terms. However, lower socioeconomic groups have not reached the same level of oral health as richer groups. This dynamics may suggest that, when major improvements in edentulism started in the lower economic groups, the majority of people in the richer groups had already improved their oral health and reached good oral health first.