A cross-sectional study of pulpal oxygen saturation in permanent incisors affected by molar incisor hypomineralisation (MIH)

Purpose To evaluate pulpal oxygen saturation (SaO₂) in permanent incisors affected by molar incisor hypomineralisation (MIH) compared with sound permanent incisors in children. Methods This cross-sectional study included 112 MIH-affected and 112 sound permanent incisors from children aged 6–12 years. Clinical examination was performed in all teeth, and periapical radiographs were obtained for MIH-affected incisors to exclude pathology and assess root development. Pulpal oxygen saturation was measured using pulse oximetry. Data were analysed using a mixed-effects linear model accounting for clustering of multiple teeth within the same individual. Complementary non-parametric analyses were also performed. Results MIH-affected incisors showed lower SaO₂ than controls (mean difference: 1.37%; 95% CI 0.90–1.84; p < 0.001). The intraclass correlation coefficient (ICC = 0.18) indicated moderate within-subject clustering. No significant differences in SaO₂ were observed according to root development stage ( p = 0.45) . Conclusion MIH-affected incisors exhibited slightly lower SaO₂ compared with sound teeth. Although statistically significant, the small magnitude of this difference limits its immediate clinical relevance and should be interpreted with caution.