Finite element analysis of a mandibular model.

A two-dimensional finite element model of a mandibular quadrant was used to examine the stresses and displacements resulting from a 100 N load placed as follows: (i) distributed on the second molar, (ii) concentrated at 30 degrees to the vertical on the second molar, and (iii) distributed on the second premolar and second molar. Each tooth was supported by periodontal ligaments, cortical and cancellous bone. The modulus and Poisson's ratios for each material were selected from accepted values. The principal stresses were determined throughout the model, with special emphasis being placed for elements in the immediate vicinity of the teeth mentioned above. It was found that for the case where the load was uniformly distributed on the second molar the stresses sigma min were mostly compressive (-) in nature while sigma max were mostly tensile (+). In the case where the load was concentrated and at 30 degrees to the vertical, the magnitude of the stresses were three to five times greater and the pattern less uniform than those resulting from the distributed load. The concentrated load at 30 degrees to the vertical resulted in higher bending stresses than the distributed load and hence higher sigma max stresses.