Abstract
Deflection of tooth and stress in its surrounding periodontium were analyzed with the two-dimensional finite element technique. Two types of finite element models of transverse sections at the mandibular first premolar were prepared. One type consisted of the tooth and its periodontium were used for analyzing the tooth deflection and its center of rotation. Another consisted of the upper components and alveolar bone was used for analyzing the stress distribution in periodontium.
The results were as follows:
1. Deflection and inclination of tooth increased as the loading angle increased and loading position was not on its axis.
2. The center of rotation appeared at the axis of apical side, about third of the tooth root, under the horizontal load. This center of rotation is called CR in the following.
3. CR was moved laterally as the loading angles to the vertical axis was decreased.
4. Total equivalent stress under the load toward the CR was less than that under the vertical loads.
5. Stresses in the horizontal direction at the height of the alveolar crest and the total equivalent stresses in periodontium increased as the moment caliculated around the CR increased. This relationship as not effected by the loading points and angles.
