Supplementary Material for: The Moderating Effect of Oral Health Literacy on the Relationship Between Socioeconomic Conditions and Untreated Dental Caries in Pregnant Women

Introduction: Dental caries is highly prevalent among pregnant women, and investigating potential modifying factors is particularly relevant for this population. This study aimed to evaluate the moderating effect of oral health literacy (OHL) on the relationship between socioeconomic conditions and dental caries in pregnant women. Methods: This cross-sectional study was performed with pregnant women attending the public health service in Santa Maria, a municipality in Southern Brazil. The Brazilian Rapid Estimate of Adult Literacy in Dentistry (BREALD-30) instrument was used to evaluate OHL. The presence of dental caries was measured using the Decayed, Missing, or Filled Teeth (DMFT) index. Socioeconomic conditions were assessed based on family income and education level. The moderating effect of OHL on the relationship between income, education, and caries (D component of DMFT) was tested using multilevel Poisson regression analyses. The results are presented as Prevalence Ratio (PR). Results: A total of 520 pregnant women were examined (response rate of 93%). Pregnant women with low educational level and low OHL exhibited a 69% higher prevalence of dental caries compared to those with higher education and high OHL. Similarly, among those with high income, pregnant with low OHL had a 57% higher prevalence of untreated dental caries than their counterparts with both high income and high OHL. Conclusion: Our findings indicate that low OHL modifies the association between socioeconomic conditions and dental caries among pregnant women. Low OHL appears to function as an aggravating factor, potentially exacerbating oral health outcomes in this population.