Abstract
The arrangement of deciduous and permanent central incisors was observed and classified using serially recorded material while subjects whose arrangement was consistent in both stages were examined with respect to tooth, dental arch and apical base morphology. The following results were obtained.
1. In the deciduous dentition, linear arrangement of the lateral incisors was most frequent in the upper jaw, while in the lower jaw a wing-like arrangement was most frequent. In the permanent dentition, the most frequent arrangement of the central incisors was the inverted wing-type in the upper jaw and the wingtype in the lower jaw, accounting for more than 50%.
2. Studies of tooth, dental arch and apical base morphology according to arrangement of the central incisors revealed differences in the rotation of the central incisors and the size of the lateral incisors in the upper jaw. The size of the maxillary lateral incisors, in particular, appeared to be closely related to winging of the central incisors.
3. Arrangement of deciduous central incisors consistent with that of the permanent central incisors amounted to 34.3% in the case of the upper jaw and 51.4%in the case of the lower jaw, demonstrating greater consistency in the lower jaw. In terms of type of arragnement, the highest rate of consistency was found in the case of type C in the upper jaw and type A in the lower jaw.
4. Subjects with consistent arrangements tended to have greater rotation of both the deciduous and permanent central incisors of the upper jaw and a shorter long-diameter of the dental arch between the deciduous canies.
5. In subjects with consistent arrangement in the upper jaw, there was a high correlation between the deciduous and permanent dentition, particulary with with respect to the width of the dental arch and apical base.
