[The first 1,000 days in molar-incisor hypomineralization and hypomineralized second primary molars]

In the first 1,000 days a large part of the enamel formation of the second primary molars, first permanent molars and permanent incisors takes place. If anything goes wrong during this period, this may have permanent implications for the enamel. If this occurs during the mineralization phase, it can be seen as hypomineralization of second primary molars (HSPM) and/or molar-incisor hypomineralization (MIH). The enamel of hypomineralized second primary molars and hypomineralized molar-incisors is less hard, less elastic and less beautiful. Due to a different composition of the enamel (more protein, fewer minerals) the attachment of restoration materials to hypomineralized enamel is more difficult. The aetiology of hypomineralized second primary molars and molar-incisor hypomineralization is multifactorial. Many potential aetiological factors have been investigated, but more insight still has to be gained into how different factors interact and what influence each factor has. Further longitudinal research into the possible aetiology of hypomineralized second primary molars and molar-incisor hypomineralization will be necessary to better understand how and why hypomineralization of the enamel occurs.