Influence of geometrical configuration of the cavity in the stress distribution of restored premolars with composite resin

The aim of the study was to analyze and quantify the influence of isthmus extension and depth of MOD cavity of upper premolars on stress distribution by means of two-dimensional finite element method. Seven different homogeneous and elastic models were created:Model 1, intact teeth;Model 2, MOD cavity with 2 mm isthmus, 2 mm depth and composite resin restoration;Model 3, MOD cavity with 2 mm isthmus, 3 mm depth and composite resin restoration;Model 4, MOD cavity with 2 mm isthmus, 4 mm depth and composite resin restoration;Model 5, MOD cavity with 4 mm isthmus, 2 mm depth and composite resin restoration;Model 6, MOD cavity with 4 mm isthmus, 3 mm depth and composite resin restoration;Model 7, MOD cavity with 4 mm isthmus, 4 mm depth and composite resin restoration. Each model were submitted to a 100N load and analyzed. The greater the depth extent of MOD cavity, the greater the stress generated in the cavity pulp wall and in the cervical region of the tooth. Increasing the extension of the cavity isthmus intensifies stress in these regions and generates stress concentration on palatal and vestibular faces. Stress generated in the cavity pulp wall was predominantly tensile stress. The loss of marginal ridges influences the stress distribution pattern of upper premolars. It is indicated restorative techniques that allow greater conservation of tooth structure.