Background: Molar-Incisor-Hypomineralisation (MIH) is a qualitative defect of 1-4 first permanent molars with or without the maxillary and mandibular permanent incisors. It seems to have been recognised first in the 1970s and prevalence varies between 2.8% and 25%, dependent upon the study.
Methods: The dental literature was searched using a number of key terms entered into MEDLINE, the reference list of each paper as located was examined for further papers that had been missed in the initial search.
Results: The review of the literature showed that teeth that are affected indicate a systemic cause at around the time of birth; investigators have put forward a number of possible causes; asthma, pneumonia, upper respiratory tract infections, otitis media, antibiotics, dioxins in mother's milk, tonsillitis and tonsillectomy and exanthamatous fevers of childhood. However, at the present time the aetiology remains unclear. Treatment of the affected permanent first molars can include restorations using adhesive intra-coronal restorations to extra-coronal restorations (e.g. preformed metal crowns). There is little evidence to support one option over another. In severe cases extraction at the optimum time may be the best option; allowing the permanent second molars to come forwards. There is little improvement in affected anterior teeth with microabrasion and direct or indirect composite resin restorations may be appropriate in some children. Ultrastructural and biochemical make up of MIH affected teeth seem to have been investigated less than other areas.
Conclusion: It is important that children with MIH are diagnosed as early as possible and managed appropriately; this will involve multidisciplinary input.