Amelogenesis Imperfecta or Molar-Incisor Hypomineralisation: A Narrative Review and Diagnostic Framework for Differentiating a Genetic From an Environmental Enamel Defect in Children.

Amelogenesis imperfecta (AI) and molar-incisor hypomineralization (MIH) are two developmental enamel defects of distinct etiologies that may present overlapping clinical features, particularly when AI manifests as hypocalcified or hypomature phenotypes. This overlap constitutes a well-recognized diagnostic challenge at all levels of dental education and has important implications for treatment planning. This narrative review aims to synthesize the available data on the clinical, radiographic, genetic, and epidemiological features that allow differentiation between AI and MIH in children and to propose a stepwise diagnostic framework to support accurate and timely clinical decision-making. A narrative review was conducted using the PubMed database, supplemented by Google Scholar. The search covered the period from January 2000 to April 2026. Studies were included if they reported clinically relevant characteristics of AI and/or MIH with sufficient detail to support differential diagnosis. A total of 16 studies were selected for the narrative synthesis. Generalized, symmetric enamel abnormalities affecting both dentitions are suggestive of AI, whereas asymmetrical, localized opacities primarily involving permanent first molars and incisors are more indicative of MIH. Taurodontism was reported more frequently in AI than in MIH. Diagnostic confusion between the two conditions is well documented in surveys of general dental practitioners, dental students, and in image-based classification models. Family history, syndromic manifestations, and next-generation sequencing support the diagnosis of AI when it is clinically suspected. Differentiating between AI and MIH requires a structured clinical assessment integrating lesion distribution, symmetry, involvement of dentitions, family history, radiographic findings, syndromic screening, and targeted genetic testing. The proposed 10-step diagnostic framework aims to reduce diagnostic uncertainty and guide referral for specialized management in pediatric patients presenting with enamel defects of uncertain etiology.