OBJECTIVES: Opacities in tooth enamel were found in 34% of 8-year-old Icelandic children in 1970. This study aimed to measure the current prevalence of non-fluorotic enamel opacities in the maxillary incisors and to determine if their occurrence was related to significant events in the medical history. DESIGN: The prevalence of demarcated enamel opacities was recorded photographically by calibrated examiners. SETTING: Subjects lived in Reykjavík, Iceland. SAMPLE AND METHODS: A random sample of 290 children aged eight years was examined in 1997-8. Parents were asked if the child had a history of (i) colic as an infant and/or (ii) repeated middle-ear infection. RESULTS: Demarcated white enamel lesions, not resembling fluorosis, were seen in 41% of children (teeth photographed wet) rising to 51% (teeth photographed dry). Enamel hypoplasia was seen in 11% of wet teeth and 15% of dry teeth. Parents of 94/288 children (32.6%) reported that their child had infant colic and 52/94 (55.3%) had received medication. Three episodes or more of middle-ear infections per year were reported for 123/290 (42.4%) children. Significant association was seen between the presence of demarcated enamel opacities and a history of otitis media. Diffuse enamel opacities, assumed to be fluorosis, were not associated with events reported from the medical history. CONCLUSIONS: Non-fluoride opacities of teeth are still prevalent in Icelandic children especially those with a history of infections in infancy. Without a careful diagnosis these opacities might be confused with fluorosis.