Abstract
The purpose of this study was to investigate the characteristics of Down's syndrome in relation to development of the teeth and the body. The subjects were 48 children with Down's syndrome (30 boys and 18 girls). Categorised by the karyotype of chromosome,43 were of the trisomic type and 5 were of the mosaic type, the children with the mosaic type all being boys. The age of the subjects ranged from 9 to 42 months. The age at the time of the eruption of the deciduous teeth was determined with semilongitudinal every 3 months data and the mesiodistal diameters of the crown of the deciduous teeth were measured on the plaster model. Above mentioned results were transformed into the standard scores. In the same manner, the data concerning the heights and the weights recorded at the same time were transformed into the standard scores. The following results were obtained;
1) Regarding all types of the teeth, the age of the eruption was delayed about 2 to 10 months longer in cases with Down's syndrome than in normal cases (Okamoto,1934), and delayed eruption especially was more evident in the anterior teeth than in the posterior teeth.
2) Regarding the dimention of the mesio-distal diameter of the crown, except for the lower lateral incisor and the lower second molar, the standard scores of all the other teeth were larger than those for the teeth in cases without the syndrome (Ono,1960). This means that the dimentions of the mesio-distal diameters in cases of Down's syndrome were generally larger than in cases without the syndrome.
3) The effects of the karyotype of Down's syndrome on the eruption were evident (p<.05), but statistically not on the height and weight.
Our results suggest that the investigation of the development of the deciduous teeth throws some light on the resolution of the developmental problems of Down's syndrome.
