Abstract
The pattern of appearance of congenitally missing teeth in the oligodontia was studied. The materials consisted of panoramic radiograms taken from 12 patients who were missing more than three permanent teeth congenitally except third molars without any systemic disease in particular. We added up every missing permanent tooth on both sides of 12 patients and designated them as the total number of missing teeth. We discussed the degree of accordance between the amount of the total numbers of missing teeth of the permanent successors from the central incisor to the second premolar and Fujita's Terminal reduction theory which had explained the human reduction pattern in teeth theoretically.
The results were as follows:
1. In the upper arch, in no case was the central incisor missing congenitally and the total numbers of missing teeth increased in order as the teeth went in a distal direction.
2. In the lower arch, in no case was the canine missing and the total numbers of missing teeth increased in order from the canine as the teeth went in both mesial and distal direction.
3. These appearance patterns of the missing teeth did not necessarily correspond to Fujita's Terminal reduction theory which presupposes that the upper and the lower arch are considered in series with the lower arch ahead, both the upper central incisor and the upper canine being the Key Teeth.
4. Assuming that the upper and the lower arch were to be independent again and the Key Teeth were the upper central incisor and the lower canine, there was no discrepancy between the result of this study and the main part of Fujita's Terminal reduction theory that the reduction would occur from the terminal sides of each tooth group.
