Abstract
During the period of the growth and development of the dental arch, mesio-distal and labio-lingual changes in the maxillary deciduous and permanent canines were longitudinally studied in children. A longitudinal series of dental casts were obtained from 50 children at 2 month intervals from the completion of the deciduous dentition up to the stable period of the permanent dentition. The subjects were divided into two groups according to the arrangement of the permanent teeth those with a normal dental arch (30 children) and those with a crowded dental arch (20 children). The mesial and distal points of the deciduous and permanent canines, and the most prominent points on their labial and lingual contours were observed longitudinally.
The results indicated that measurement points of the deciduous canines of the normal and crowded groups move in the mesial and labial direction. When the amount of movement of the normal group was compared to those of the crowded group, the normal group showed a larger movement than the crowded group. Measurement points of the permanent canines of both groups moved in mesial and lingual direction. When the amount of movement of the normal group was compared to that of the crowded group, it was found that the normal group moved more mesially than the crowded group, and the crowded group moved more lingually than the normal group. When the distal point of the permanent canine was compared with the point of the deciduous canine at the exfoliation period in the normal dental arch group,20 bilateral canines did not show any apparent changes, but 40 canines had moved more than 1 mm in the mesial direction.
In the crowded dental arch group,19 bilateral canines did not show any apparent changes,17 canines had moved more than 1 mm in the mesial direction, and 4 canines had moved distally more than 1 mm. In the normal arch group, the permanent canine was in almost the same position or there was a more mesial position for the deciduous canine. In the crowded arch group, the permanent canine might have drifted distally.
