Purpose. This study was designed to determine the prevalence of developmental enamel defects in a group of Egyptian children and to determine the most common causes of these developmental enamel defects. Subjects and Methods: A total of 1500 children (4-14 years old, 700 boys and 800 girls) were randomly selected from the health insurance public daycare centers. For each child a clinical examination was performed according to the 2013 WHO dental caries criteria and the modified DDE index (FDI, 1982). Children were divided into three groups, according to the type of dentition as
follows, group (A) included “692" children and representing the children who had only deciduous dentition, group (B) included “688" children and representing the children who had mixed dentition and group (C) included “120" children and representing the children who had only permanent dentition. Results: Prevalence of enamel defect were observed in 22.5% of cases. Conclusion: Prevalence of enamel defect were observed in 337 cases with the most common defect was demarcated opacity which was found in 197 cases (13.1%). There was a statistically significant association between presence of enamel defects and previous disease. Previous surgery, previous radiation, previous medication and previous hospitalization. Also, high mean dmf, def and DMF indices, high mean GI. There was no statistically significant association between presence of enamel defects and maternal history during pregnancy, present disease, present intake
of medication and familial history of disease