Time-dependent fracture probability of bilayer, lithium-disilicate-based, glass-ceramic, molar crowns as a function of core/veneer thickness ratio and load orientation.

Unlabelled: Recent reports on bilayer ceramic crown prostheses suggest that fractures of the veneering ceramic represent the most common reason for prosthesis failure.

Objective: The aims of this study were to test the hypotheses that: (1) an increase in core ceramic/veneer ceramic thickness ratio for a crown thickness of 1.6mm reduces the time-dependent fracture probability (Pf) of bilayer crowns with a lithium-disilicate-based glass-ceramic core, and (2) oblique loading, within the central fossa, increases Pf for 1.