[Survey and analysis of the normal deciduous teeth arch in children 3 and 4 years of age]

The normal deciduous teeth arch of 200 cases of 3 and 4 years old children from 13 kindergartens in Shanghai were investigated and analysed. The result showed that the bilateral form was more than mixed form in terminal plane. In bilateral form, mesial step type was the most and vertical plane type second, the least one was distal step type. The spaced type dental arch was more than closed type previously. There were 90.63% arch with both primate space and developmental space. The spaces were more in BC and CD, and less in DE. There was no difference of the equal values of teeth arch in age, but difference in sex. The function of physiological space and the clinic significance of values of terminal plane and teeth arch were discussed. These data may provide the reference to clinical observation and calculation.