Aims: This was to determine the prevalence of Molar-Incisor-Hypomineralisation (MIH) among children participating in the Dutch National Epidemiological Survey of 2003 and to compare the prevalence data with that found in the previous survey of 1999 when MIH was found in 9.7% of 11-year-old Dutch children.
Methods: The survey took place in the same four cities as the previous survey in 1999. In 442 9-year-old children born in 1994, first permanent molars and all permanent incisors were examined for demarcated opacities, post-eruptive enamel breakdown, atypical restorations and extractions due to MIH. Children were considered as having MIH, when at least one molar was affected, with or without involvement of the incisors.
Results: Of the children examined 63 or 14.3% had at least one affected molar with hypomineralisation defects. Of those children with MIH only demarcated opacities were present in 35 (55.6%), while 13 (20.6 %) had at least one tooth with occlusal breakdown in addition to opacities, and in 15 (23.8%) atypical restorations were found. No teeth had been extracted due to MIH. Of the children with MIH there were 36 (57.1%) who had both molars and incisors affected.
Conclusions: A significantly higher prevalence of MIH has been found in Dutch 9 year-old children in the last National Epidemiological Survey of 2003 as compared with to the Survey of 1999.