Beyond Universal Coverage: The Magnitude of the Oral Health Equity Gap Between Socially Excluded Children and a...

Dental caries is socially patterned, but the magnitude of the inequality associated with social exclusion is difficult to quantify when populations are compared across different countries and health systems. This study estimated the oral health gap between socially vulnerable children attending escuelas singulares and a contemporaneous reference paediatric population attending university dental clinics within the same city and health-system context.

A cross-sectional analytical study was conducted in 231 children aged 6-12 years in Valencia, Spain: 129 from two state-funded schools serving communities at high risk of social exclusion, hereafter referred to as escuelas singulares (Colegio Madre Petra, n = 64; Colegio Santiago Apóstol, n = 65), and 102 reference children examined at the University Dental Clinics of the Catholic University of Valencia. Caries experience (DMFT/dmft-derived global score), the Simplified Oral Hygiene Index (OHI-S), toothbrushing frequency and sugar consumption were recorded under standardised conditions. The groups were compared with non-parametric tests, and multivariable logistic and modified Poisson regression models estimated the independent association (adjusted OR and adjusted prevalence ratio, respectively) between school context and the presence of caries, adjusting for age, sex and behaviours.

Caries experience was markedly higher in vulnerable children (global caries score 4.07 ± 3.44 vs. 0.61 ± 1.96; p < 0.001), with a caries prevalence of 76.0% vs. 13.7% (a prevalence ratio of 5.5) and a 6.7-fold higher mean burden. Only 24.0% of vulnerable children were caries-free versus 86.3% of reference children. Vulnerable children also showed poorer oral hygiene (OHI-S 1.49 ± 0.84 vs. 0.19 ± 0.34; p < 0.001), less frequent brushing (50.4% vs. 79.4% brushing ≥ twice daily; p = 0.002) and higher sugar consumption (p < 0.001). After adjustment for age, sex, brushing and sugar, attendance at an escuela singular was associated with an adjusted prevalence ratio of 5.4 (95% CI 3.3-8.9; primary effect measure) and, in a secondary logistic model, with an adjusted OR of 20.5 (95% CI 9.6-43.8).

Within a single high-income setting with formally universal health coverage, social exclusion was associated with a very large, graded excess of childhood caries that the measured behavioural differences alone were unlikely to explain, underscoring the role of social and structural determinants beyond individual behaviours. These cross-sectional findings are consistent with proportionate-universalism strategies (targeted, school-based preventive and restorative care embedded within the universal system), since formal coverage alone may be insufficient to achieve oral health equity.