The characteristics of the deciduous dental arch form of children in Changchum-city, China

It is important to know racial differences in the characteristics of the dental arch form from the view point not only of dental interests but also of anthropology. We got an opportunity to investigate the status of oral condition of children living in the Changchum-city, Jilin Province in China. The size and the form of the deciduous dental arch were measured using plaster casts prepared from the impressions taken at the time of oral examination. The same measurement was conducted using the dental plaster cast of the Japanese children and the size and shape of the dental arch were compared between the Japanese and the Chinese children. The subjects were the Chinese children who had the Hellman IIA dentition lining in Changchum-city. The average age of the Chinese children was 9 years and 4 months and that of the Japanese children was 4 years and 1 month. The measurement results showed that the Chinese children were bigger than Japanese children in every measurement items. As for the dental arch form, Japanese children had a U-shaped arch form with wider width in the front part of the dental arch. On the other hand, the Chinese children had a half-circle-shape arch form that the front arch width was not so wide but that of the back was wide.