Abstract
The tooth supporting system was analyzed by a three dimensional Finite Element model of the lower premolar region in accordance with the anatomical structures and their material properties. Tooth mobility and the Fourier spectrum of its acceleration responses were calculated from the behavior of the model under static and dynamic loading. The responses of the model were consistent with that of behavior in vivo, which suggests that the model is plausible and reflects the structure and mechanism of the tooth supporting system. The results were, 1) The elastic response depends on the direction of the periodontal fiber bundles and their mechanical properties. 2) The viscosic response depends on the damping coefficient of the periodontium. 3) The frequency spectrum of a normal tooth showed two peaks at about 600 and 1600Hz. 4) The model response of an abnormal tooth presented an increasing frequency spectrum level due to a diminishing elastic coefficient, tricuspidisation of the 600Hz peak at 380, 600 and 800Hz due to a reduction of the viscosic coefficient, and tricuspidisation of the response (1600Hz peak) of the tooth, when the upper one thirds of alveolar bone was lost at 1300, 1600, and 1900Hz. These results clarified anatomical structure and material property on which the viscoelastic behavior of the periodontium depends.
