Abstract
A three-dimensional finite element method was applied to calculate elastic stress distributions of a castable ceramic crown on an upper first premolar. Acting a uniform pressure on the cusp, tensile stresses were produced near the central groove and at the boundary between the crown and abutment tooth. When the angle of the groove, α, the radius of the groove bottom, γ, and the thickness of the crown, t, are small, the tensile stress at the groove becomes large and the groove may be attributed to the fracture of the crown. In crowns having large values of α, γ and t, maximum tensile stress is produced at the crown-tooth boundary. But the magnitude of this stress is very small in comparison with the tensile strength of a castable ceramic. In order to prevent the fracture of the crown, groove angle α, groove radius γ and crown thickness t should be increased as much as possible.
