Tooth malalignments in Chilean children with Down syndrome.

The present study analyzes the frequencies and types of anomalies in tooth alignment in a sample of 136 children with Down syndrome, 147 mentally-impaired individuals without Down syndrome, and 149 normal individuals. Patients with Down syndrome showed a higher frequency of malalignments in both the deciduous and permanent dentitions compared with the children in control groups. In the three groups studied, the frequency of malalignments was higher in the permanent than in the deciduous dentition. In the deciduous dentition, the frequency of malalignments in the three groups was similar in the maxilla and mandible, and in both boys and girls. In the permanent dentition, the frequency of malalignments was higher in Down and mentally-impaired girls without Down syndrome, while the frequency of malalignments in the mandible was only increased in mentally-impaired individuals who did not have Down syndrome. In the deciduous dentition, the Down group presented a higher frequency of malalignment in the upper central incisor, lateral incisor, and canine regions compared with the normal children. When comparing teeth of Down children with those of mentally-impaired individuals who did not have Down syndrome, differences in malalignment were observed only in upper central incisor and canine regions. In the permanent dentition, the Down group showed a higher number of tooth malalignments than the normals (13 out of 28 teeth). A comparison of Down with non-Down mentally-impaired individuals, revealed only 8 teeth out of 28 were different. The most frequent malalignments in the deciduous dentition in Down patients were mesiopalatal, mesiolingual, and mesiovestibular. In the permanent dentition, the most frequent malalignments were distopalatal or distolingual.