Abstract
In the first report, the two dimensional finite element analysis was performed on the bridge model through a computer in order to learn the effect of such two factors as the resorption of the alveolar bone and the number of abutment teeth against the stress distribution of the supporting tissue of the brige whitch is subject to the occlusal force. Furthermore, the results of the finite element analysis under vertical load were compared between the three and the two dimensional models of single rooted tooth in order to study the relation between the threedimensional resorption state of the alveolar bone and the two dimensional model.The models used in study, however, were extremely simplified. Moreover, the periodontal membrane was not modeled and the influence of the lateral load was not considered. Based on these background, in this report, more practical three dimensional model was created including the periodontal membrane. In addition, two two-dimensional models of bucco-lingual and mesiodistal cross sections of three dimentional one were created.
The loading direction and the degree of alveolarbone defect were varied by each model. The load was given vertically, bucco-laterally and lingual-laterally. Alveolar bone defect were three cases of 0, 1/3 and2/3 defect of the root length. The comparison of the results of the finite element analysis performed on the total of 18 cases and those of first report resulted in as follows.
1. The periodontal membrane has stress breaking effect on the alveolar bone surrounding teeth.
2. In the extremely-stressed part, the three dimensional model tends to show higher stress value than the two dimensional one.
3. In the laterally loaded case, the load part generates tensile stress and opposite side, compressive stress around the ceavical part. Around the apical part, the two stresses are reversed.
4. As bone defect progresses, the stress to be generated increases. For exsample, equivalent stresses generated atthe periodontal membrane in the vertically-loaded three dimensional model were 1.0, about 1.5 and about 2.3 in terms of 0, 1/3 and 2/3 defect respectively.
