Experimental stress analysis of dental restorations. II. Two-dimensional photoelastic stress analysis of crowns.

Abstract The general stress distribution in full crown restorations was investigated using a two-dimensional photoelastic stress analysis method. Crowns on tipped molar abutments as well as on normally aligned molars were analyzed. The maximum compressive stresses on the interior of crowns were generally found to be on the reduced cusp surface of the restorations. Maximum tensile stresses were observed in the central fossa and along the axis of symmetry of the crown, when the crowns were loaded bilaterally to simulate oral conditions. Stresses were also investigated at the free boundaries of the crown, and tensile stresses were observed at the cervical margins of the restoration with compressive loads of 133 pounds and at a cusp angle of 39 degrees.