[Molar incisor hypomineralization].

Molar incisor hypomineralization (MIH) describes a developmental enamel formation disorder caused by defective calcium and phosphate deposition by the ameloblasts during enamel matrix formation and enamel maturation. The first permanent molars are affected. The first permanent incisors may or may not be affected (Fig. 1, 2). The prevalence is 10 to 19%. The etiology of MIH is still unknown.