Evaluation of socioeconomic inequalities in dental caries levels in Chilean children aged 6 years, 2008-2023

Dental caries is the most prevalent chronic disease in children worldwide, disproportionately affecting socioeconomically disadvantaged populations. In Chile, national data from 2007 reported significant inequities in dental caries among six-year-old children, with higher prevalence in rural and low-income areas. This study aimed to evaluate socioeconomic inequalities in the distribution of dental caries among Chilean children aged 6 years from 2008 to 2023, considering recent public health interventions. This ecological study utilized anonymized routine health records from the Chilean public health system and socioeconomic data at the municipal level, covering 2008-2023, with data from up to n = 323 municipalities nationwide. Caries experience was measured as the proportion of six-year-old children with decayed, extracted, or filled primary teeth (dmft > 0) per municipality and year, following WHO criteria. Socioeconomic inequalities were assessed using the Slope Index of Inequality (SII) and Relative Index of Inequality (RII), with linear regression models to evaluate trends over time. A reduction in caries experience among six-year-old children - decreasing from 75.8% in 2008-2011 to 60.4% in 2020-2023 - was observed. Absolute inequality in caries experience between the least and most advantaged groups declined from 14.9% in 2008-2011 to 9.5% in 2020-2023. However, profound socioeconomic inequities in caries distribution persisted throughout the study period. The findings indicate a trend towards reduced socioeconomic inequalities in dental caries among six-year-old Chilean children, possibly influenced by preventive public health programs. Nevertheless, significant inequities and high caries levels remain, highlighting the need for sustained and equitable oral health interventions.