Stress analysis of mandibular incisors with different overbite

Objectives: To investigate the distribution of stress on the surface of alveolar bone of mandibular incisors with bone loss under different overbite. Methods: A three-dimensional finite element model of mandibular incisor with healthy alveolar bone height, named Model 1, was constructed. Then the alveolar bone of model 1 was lowered gradually to construct Model 2(Bone loss was one fourth of the root), Model 3(Bone loss was one third of the root), Model 4(Bone loss was half of the root), Model 5 (Bone loss was the two third of the root) and Model 6 (Bone loss was the three fourth of the root). By three-dimensional finite element analysis, the Von Mises stresses of models with different overbite were observed when different loadings of 0, 15 and 30 degree were applied. Results: For Model 1 with normal overbite, the maximum stress under vertical loading was 13.171MPa, located in the apical and apical third region of the root. For the same model, the stress decreased and the area of the distribution of maximum stress increased with the deepening of overbite. From Model 1 to Model 6, the stress increased slowly with bone loss when alveolar bone loss was less than half of the root length. Once bone loss was greater than half of the root length, the stress increased significantly and concentrated on the alveolar crest. Conclusions: As far as overbite was concerned, it do not cause increase in stress and stress concentration. However, with the co-existence of lock bite and deep overbite , the increase of stress and the stress concentration may happen. As a whole, overbite do not change the tendency of stress concentration on the alveolar crest with bone loss. If bone loss is not less than half, the stress increased significantly and concentrated on the alveolar crest.