Fracture of a veneered-ZrO2 dental prosthesis from an inner thermal crack

• Complex failure of a dental restoration from an internal, thermally induced defect.
• Fracture origin was located between two layers of the veneering ceramic.
• Fracture initiation was most probably due to incremental sintering of the veneer layers assisted by mixed mode loading conditions.

Here we describe the fractographic analysis of a veneer-ZrO2 single-unit dental prosthesis that fractured in a shell-like manner. Analysis of the retrieved fragment revealed that the crack originated in the bulk of the veneer from a thermal flaw located between two layers of the veneering material. Using the measured flaw plane we showed that the conditions of loading at fracture were complex and probably involved important tangential components.