Molar incisor hypomineralisation (MIH) is a widespread and problematic tooth disease. The cervical areas are mainly spared. The affected enamel on the other hand differs from normal enamel by reduced hardness, lower mineral content, increased porosity, higher carbonate and protein content as well as anomalies of the ultrastructure. There have also been reports of bacterial contamination through intact surfaces, anomalies in the dentine and changes of the pulp. Poorer long-term prognoses and restorative results as well as difficulty in patient treatment in connection with these factors make careful assessment necessary as to whether the direct transfer of caries treatment concepts to MIH treatment is practical, even though the remineralisation media used against caries can evidently improve the enamel properties with MIH.