Sequence of eruption of deciduous dentition in a Chilean sample with Down's syndrome.

The eruption of the deciduous teeth in Down's individuals is reportedly delayed, but the extent of delay in comparison to normal children has been little studied. The eruption characteristics of the deciduous teeth in a sample of Chilean individuals with Down's syndrome were compared with those of the normal Chilean population. The sample consisted of 255 Down's individuals (all with trisomy 21), 127 males and 128 females. Boys with Down's syndrome showed significantly delayed eruption in six teeth: in the maxilla the right central incisor and right and left lateral incisors, and in the mandible the right central incisor and right and left canines. Girls with Down's syndrome showed significant delays in the eruption of 11 teeth: in the maxilla the right and left lateral incisors, right and left canines and first left molar, and in the mandible the left central incisor, right and left lateral incisors and canines and second right molar. The chronological sequence of eruption in Down's children was not completely different from that of normal individuals. With a few exceptions no significant departures from Gaussian distribution were found in the age of eruption among both normal and Down's individuals. The variance was significantly larger in cases of Down's syndrome.