Finite element stress analysis of restored teeth

Abstract

A bucco-lingual descretization of a sectioned molar tooth was developed from which a plane stain finite element analysis was utilized to determine the principal, shear and effective stresses at each of nine Guass points within each element. The model was uniformly loaded along the inclined occlusal surfaces to a level of 100 Newtons. The maximum effective and principal stresses were always at the fissure between the cusps at a value of 5.4 MPa in the enamel of sound whole tooth and 5.35 MPa in the amalgam of a pinned restoration. It was generally found that the insertion of a liner attenuates the stress dependent on cavity size. Wider cavities tend to reduce the maximum effective stresses. Stresses at the liner amalgam interface are lower than those at the tooth fissure, suggesting that fracture or deformation is unlikely to initiate from the amalgam base and propogate to the occlusal surface. Insertion of stainless steel retaining pins returns the maximum effective stress at the fissure to the higher levels found for a class I restoration.