Aims: These were to determine the prevalence of MIH in a group of primary school children in Kaunas, Lithuania and to compare the prevalence of MIH in Lithuania with the prevalence in other countries using published data.
Methods: First permanent molars and all permanent incisors were examined in 1277 children, aged 7 to 9 years and having at least one erupted permanent molar, for demarcated opacities, post-eruptive enamel breakdown, atypical restorations and extractions due to MIH, according to the criteria, provided by the EAPD experts. Examinations were performed by two calibrated observers (k=0.829).
Results: Of all the children 190 (14.9%) had hypomineralization defects in at least one index tooth, 124 (9.7%) had at least one affected molar and were considered as having MIH. Only demarcated opacities were present in 68 (54.8%) of children with MIH, 35 (28.2 %) had at least one tooth with breakdown, 21 (16.9%) had atypical restorations. No teeth had been extracted due to MIH. Children with 3-6 affected teeth were 3.5 times more likely to have enamel breakdown and/or atypical restorations when compared with the children having only one or two affected teeth. Of the 124 children with MIH 96 (77.4%) had lesions only in molars, 28 (22.6%) had both - molars and incisors - affected.
Conclusions: MIH was common among 7-9 years old Lithuanian children; majority of the affected children were affected mildly. Severity of the lesions was increasing with the number of affected teeth. Compared to the other studies MIH in Lithuania was moderately prevalent.