Distribution and Clinical Characteristics of MIH in Schoolchildren From the Central Peruvian Jungle: A Cross‑Sectional Study

Background Molar incisor hypomineralisation (MIH) is a developmental enamel defect that predominantly affects first permanent molars and frequently involves incisors. However, evidence on MIH prevalence and clinical presentation in jungle regions is limited. Aim To determine the distribution and clinical patterns of MIH among schoolchildren in the Central Jungle region of Peru. Materials and Methods This cross‐sectional study included 1500 schoolchildren aged 6–12 years from two public schools in Peru’s Central Jungle region, recruited through stratified random sampling. Two calibrated examiners diagnosed MIH using European Academy of Paediatric Dentistry (EAPD) criteria (inter‐examiner κ = [0.87]; intra‐examiner κ = [0.89]). Categorical variables were analysed using Pearson’s chi‐squared and Fisher’s exact tests ( α = 0.05, 95% CI). Results MIH prevalence was 18.8% (95% CI: [17.0–20.0]). First permanent molars were predominantly affected (upper: 84.8%, 285/336; lower: 90.9%, 288/317) compared to incisors. Pattern I distribution occurred in 78.7% of cases, while patterns II/III (21.3%) showed significant male predominance ( p = 0.008). Molars exhibited significantly greater severity ( p = 0.001) with white–cream opacities (28.5%) and predominantly Type III lesions, presenting higher post‐eruptive breakdown and atypical caries rates. Incisors displayed mainly mild Type I demarcated opacities. Upper lateral incisors demonstrated left‐sided predominance ( p = 0.016). Conclusion MIH prevalence was 18.8% among schoolchildren in Peru’s Central Jungle region. First permanent molars were predominantly affected (upper: 84.8%; lower: 90.9%) compared to incisors. Pattern I distribution occurred in 78.7% of cases, while patterns II/III (21.3%) showed significant male predominance. Molars exhibited greater clinical severity with white–cream opacities, Type III lesions, and higher rates of post‐eruptive breakdown and atypical caries, whereas incisors presented mainly mild demarcated opacities.