Supplementary Material for: Municipal oral healthcare coverage and dental caries among Brazilian children

Introduction: Universal coverage for oral healthcare is expected to improve population oral health. However, empirical evidence to substantiate this expectation is scarce and inconsistent. This study investigated the association between municipal oral healthcare coverage and dental caries among 5-year-old children. Methods: This study pooled together individual-level data from 7185 five-year-old children who participated in the National Oral Health Survey - SB Brasil 2023 and monthly data on municipal oral healthcare coverage from January 2019 to December 2023. Dental caries was determined at cavity level in clinical examinations and summarised using the numbers of decayed teeth (dt), missing and filled teeth (mft) and decayed, missing and filled teeth (dmft). Group-based trajectory modelling was used to identify four distinct classes of municipal oral healthcare coverage: always-low, medium-low, medium-high and always-high. Multilevel negative binomial regression models, with children nested within municipalities, were fitted to test the association between municipal oral healthcare coverage and each caries measure, adjusting for demographic factors, socioeconomic conditions and oral healthcare-seeking behaviour. Results: The variance partition coefficient of the empty model (no predictors) indicated that 4.1%, 3.1% and 4.4% of the variance in the dmft, dt and mft scores was attributable to differences between municipalities. Greater municipal oral healthcare coverage was not associated with the dmft and dt scores after adjusting for covariates. In contrast, municipal oral healthcare coverage was associated with the mft score after adjustments. Children in municipalities with medium-low (1.09, 95%CI: 0.72-1.66), medium-high (1.45, 95% CI: 0.93-2.26) and always-high coverage (1.50, 95%CI: 0.88, 2.56) had on average higher mft scores compared to those in municipalities with always-low coverage (p-value for trend=0.047). Conclusion: This study shows that greater oral healthcare coverage was positively associated with more caries treatment experience but not with current untreated disease.