Objective: To estimate the prevalence and describe the distribution of demarcated opacities and possible consequences of this condition in permanent 1st molars and incisors in Danish children.
Material and methods: Among all 6 to 8-year-old children in two municipalities, 745 (83.6%) were clinically examined for the occurrence of creamy-white or yellowish-brown demarcated opacities, posteruptive breakdown of tooth substance in relation to the opacities, atypical restorations, and extractions, i.e. restorations or extractions as a result of the occurrence of demarcated opacities.
Results: In 647 children with four fully erupted permanent 1st molars, the prevalence of demarcated opacities and of lesions with loss of tooth substance due to demarcated opacities in any 1st molar was 37.3% (95% confidence interval (95% CI) 33.6-41.0%) and 6.3% (95% CI 4.7-8.5%), respectively. Permanent incisors were 2.5 times more frequently affected among children with one or more affected permanent 1st molar than among children with no such teeth. Demarcated creamy-white opacities were the type of lesion found most frequently, and the most frequently affected tooth types were the upper central incisors followed by 1st molars.
Conclusions: Nearly half of the examined 6 to 8-year-old children had permanent 1st molars or incisors with demarcated opacities. More than 6% of the children had macroscopic loss of tooth substance due to demarcated opacities.