Molar-Incisor Hypomineralization and Resin Infiltration

This dual-design study-encompassing a cross-sectional descriptive phase and a controlled clinical trial-aims to investigate the prevalence and associated risk factors of Molar Incisor Hypomineralization (MIH), while evaluating the therapeutic efficacy of resin infiltration (ICON) for treating mild MIH lesions in permanent incisors among school children aged 7 to 11 years across selected primary schools in Northern Vietnam. The primary research questions seek to delineate the current epidemiological profile of MIH alongside its pre-, peri-, and postnatal biological determinants, while assessing the longitudinal clinical outcomes of resin infiltration (ICON) regarding color change ΔE, lesion depth penetration, and aesthetic restoration compared to control groups. In the interventional phase, outcomes of the resin infiltration cohort will be evaluated against control protocols (such as topical fluoride varnish application or observation/untreated controls) to quantify improvements in color stability, remineralization, and defect dimensions. Participating pediatric subjects will undergo comprehensive oral examinations to index MIH severity on first permanent molars and incisors, alongside standardized questionnaire-based interviews with guardians to record medical history. Children presenting with mild incisor defects enrolled in the clinical trial will receive treatment with resin infiltration or comparative controls, followed by standardized digital photography and spectrophotometric color assessment (using the VITA Easyshade V device), with structured post-operative follow-up evaluations scheduled at baseline 1 month, 2nd month, 3rd month, 6th month, and 12th month to measure long-term treatment longevity and outcomes.

Inclusion Criteria: * Children aged 7 to 11 years. * Children diagnosed with mild Molar-Incisor Hypomineralization (MIH) according to EAPD criteria on permanent incisors. * Permanent incisors with intact anatomical shape, showing smooth enamel surfaces or minor defect depth without post-eruptive enamel breakdown (PEB). * Children and parents/guardians willing to participate and sign the informed consent form. Exclusion Criteria: * Children with severe MIH lesions accompanied by post-eruptive enamel breakdown (PEB), atypical restorations, or dental caries. * Permanent incisors with developmental anomalies, fluorosis, amelogenesis imperfecta, dentinogenesis imperfecta, or severe enamel hypoplasia. * Teeth undergoing active orthodontic treatment or presenting with fixed orthodontic appliances. * Non-vital teeth, teeth with symptoms of pulpitis, apical periodontitis, or history of endodontic treatment. * Children with systemic diseases, chronic physical/mental conditions, or severe uncooperative behavior during dental procedures.