Ectopic eruption of the maxillary first permanent molars in children with cleft lip and/or palate.

The purpose of this study was to analyse the prevalence of ectopic eruption of maxillary first permanent molars in children with cleft lip and palate, and evaluate the influence of both local and genetic factors. Radiographs from 225 children, 125 girls and 100 boys, were studied. The prevalence in cleft children was found to be more than four times higher than in non-cleft children (4.3 per cent). In children with cleft lip or cleft lip and alveolar process the prevalence was 15.4 per cent and in children with cleft palate only it was 28.8 per cent. A notable finding is that the ectopically erupting molar was not related to the cleft side. In children with surgically corrected cleft lip in combination with cleft palate or with cleft palate only, the surgery may have influenced the prevalence to some extent, but the main explanation for the increased prevalence of ectopic eruption in cleft children is a genetic aetiology.