Abstract
The prevalence of the different types of enamel defects seen in 696 nine year-old children is described and related to the dental information recorded at age five. The FDI Index of Developmental Defects of Dental Enamel was used to record enamel defects in the permanent teeth, which were dried but not cleaned before being examined. Fifty-seven per cent of the children had at least one tooth with defective enamel. The single, demarcated, white opacity was the most common type of defect, being seen in 31 per cent of children. Approximately 40 per cent of these defects were <2 mm in diameter. Diffuse opacities, although present in fewer children, affected more teeth per child. The prevalence of the diffuse opacities in the 570 children exposed to fluoridated water all their lives was not significantly higher than that recorded for the 51 children using non fluoridated water. More children and more teeth with hypoplastic lesions were seen in the group of children with visible evidence of trauma to their deciduous incisors recorded at age five.