Children’s oral health is commonly affected by dental caries and molar–incisor hypomineralisation (MIH), conditions that can impair chewing, appearance, and social well-being. In Spain, variations in prevalence have been observed across regions and social groups, especially in rural settings and among children with immigrant backgrounds. This study aimed to examine the presence of dental caries and MIH in 6 to 7-year-old children from the towns of Mazagón; Palos de la Frontera, and San Bartolomé, identifying social and clinical factors linked to oral health disparities. A total of 229 children from primary schools participated in this cross-sectional survey. Clinical examinations assessed dental status, while structured interviews gathered anthropometric, sociodemographic, and behavioural data. Associations between risk factors and outcomes were explored using univariate and multivariate logistic regression. The Huelva Ethics Committee approved the study protocol. More than half of the participants (53.3%) presented with caries (DMFT ≥ 1), with mean DMFT and dft values of 1.78 and 0.31, respectively. MIH was diagnosed in 32.8% of the children, predominantly affecting the first permanent molars (teeth 36 and 26). Regression analyses indicated that caries was independently linked to African (OR = 7.47; 95% CI: 2.84–23.8) and European (OR = 4.56; 95% CI: 1.26–22.3) parental origin, poor oral hygiene (OR = 3.07; 95% CI: 1.60–6.03), and the presence of MIH (OR = 3.20; 95% CI: 1.64–6.42). Children living in San Bartolomé had increased odds of MIH (OR = 2.90; 95% CI: 1.21–7.45). The Condado-Campiña region exhibits elevated levels of caries and MIH, surpassing national averages, reflecting inequities shaped by social factors (migrant status, residence) and oral health conditions (hygiene, MIH). Preventive strategies, including culturally adapted oral health education and equitable access to dental care, are urgently needed for vulnerable populations.
