Molar incisor hypomineralization (MIH) is one of the most pressing issues in paediatric dentistry. It is a qualitative enamel defect of systemic origin that affects at least one first permanent molar and can also be associated with permanent incisors. However, the same defects have also been observed on primary molars and other permanent teeth. Hypomineralised enamel has less distinct prisms edges and crystals and the interprismatic space is more marked. Children with MIH undergo dental treatment nearly 10 times more than unaffected children. Preventive treatment following the diagnosis of MIH should take into account patient's age and collaboration, patient's caries risk, type and extension of demarcated lesions and hypersensitivity. Risk assessment and early diagnosis are key factors to an effective and conservative treatment
