Abstract
We conducted an investigation of cases of supernumerary teeth in the upper incisor region. The investigation was based on the examination of the out-patients who had visited the Pedodontic-clinic of Tokyo Medical and Dental University during past 8 years. The subjects consisted of 403 boys and 138 girls. The results were summarized as follows:
1. In most cases, the presence of supernumerary teeth had been found in children from 6-8 years of age.
2. About 65% of the cases had one supernumerary teeth, and 34% of the cases had two supernumerary teeth. Moreover, with boys, a few cases had three or four supernumerary teeth.
3. Upon examination of X-rays, with respect to the direction of the crown,52.8%of the supernumerary teeth were normal,44.4% were inverted and 2.9% were horizontal.
4. On examination of the dental plasters, it was found that the mesiodistal crown diameter of each tooth was not significantly different from that of the normal occlusion.
5. In cases in early mixed dentition, the bicanine width was found to be larger than that of the normal occlusion, and it was suggested that the anterior arch form was larger than the normal one.
