Restoration of Permanent Molars Affected With Molar-incisor-hypomineralization (MIH) Among a Group of Egyptian Children Using Composite Restorations or Preformed Metal Crowns

Inclusion Criteria: * Children with MIH in one fully erupted molar or more. * Age ranging from 7-12 years. * Cooperative children * Good general health. Exclusion Criteria: * patients participating in other experiments. * Patients with parents planning to move away within the following year. * Patients with only mildly affected MIH molars that do not require extensive restorative treatment. * MIH-affected molars that have a very poor prognosis and require extraction. * First permanent molars that are affected with other developmental defects, such as hypoplasia, dental fluorosis or amelogenesis imperfecta