[Anomalies in the number of permanent teeth in orthodontic patients in 2 localities in Croatia].

The authors investigated the frequency of anomalies among permanent teeth in two regions in Yugoslavia--Istria and Slavonia--in a group of 4449 orthodontic patients (1890 boys and 2559 girls, age 6-18 years; in Istria: 1060 boys and 1341 girls, in Slavonia: 830 boys and 1218 girls). The anomalies were diagnosed by clinical examination and by orthopantomogram analysis. The anomalies were significantly more frequent in children of Istria compared to the ones of Slavonia, i.e. hypodontia was found in 6.25% versus 2.34% and hyperdontia in 1.37% versus 0.63%. Hypodontia in the mandible prevailed among the children in Istria while that in the maxilla among the children in Slavonia. The differences in the sequence of the hypodontia frequency for each tooth in both sexes have been established separately for the two regions.