Molar-incisor hypomineralization (MIH), dental fluorosis, and caries in rural areas with different fluoride levels in the drinking water.

Aim: This study determined the prevalence of molar-incisor hypomineralization (MIH) and its association with dental fluorosis and caries in children living in rural areas in north-eastern Brazil who are exposed to residual fluoride (F) levels in the drinking water.

Design: A census was carried out with 610 schoolchildren aged 6 to 12 years. The European Academy of Paediatric Dentistry criteria, Thysltrup and Fejerskov index, and World Health Organization index were used for diagnosis of MIH, dental fluorosis, and caries detection, respectively. The association between the outcome and exposure variables was determined by robust Poisson regression (P < .05).

Results: Water F-levels varied from 0.06 to 1.98 ppm. MIH was not related to fluoride levels in the drinking water, but it showed an inverse and direct correlation with dental caries and fluorosis, respectively. Children with MIH had a higher DMFT, and severe MIH cases were most frequent in children with dental fluorosis.

Conclusion: Drinking water F-levels were not directly related to the occurrence of MIH in schoolchildren. The severity of MIH, however, was likely to be associated with dental fluorosis in areas with moderate to high fluoride levels in the drinking water.