Abstract
The purpose of this study was to examine the differences in the time of eruption and calcification of the permanent dentition between skeletal class III and class II groups, and also to examine the relationship between the time of eruption and the type of malocclusion. Fifty-three children aged 7-10 years were selected. Of these,27 children were Angle's class III with minus ANB and 26children were Angele's class II with 5 or more ANB. Panoramic X-rays and chephalometric X-rays were used. The panoramic radiographs showed that the calcification of the upper second molars in class II were earlier than that in class III using Nolla's classification. In both the upper and lower molar regions, the time of eruption and calcification were earlier in the upper second molars than in the lower in class II. In contrast, the time of eruption and the calcification were earlier in the lower second molars than in the upper in class III. The time of eruption and the calcification of the upper molars were significantly related to the length of the ANS-PNS. The longer the ANS-PNS, the earlier was the time of eruption and the. calcification. There was a significant relationship between the ANB angle and the time of eruption, as well as, the ANB angle and the calcification.
