EXPERIMENTAL STUDY ON THE FRACTURE MODES OF SECTIONED ALL-CERAMIC CROWNS UNDER CONTACTING LOADS

The experimental investigation was carried out to explore the fracture mechanism of all-ceramics under occlusal contact loads in this paper. A novel sectioned crown specimen was designed such that digital image correlation (DIC) can be used to identify the crack initiation and propagation in ceramic layers. Results from the flat trilayer sectioned specimens had good agreement with the well established fracture theory for ceramics, while the facial-lingual sectioned crown has debonding at crown shoulder besides the regular conic and radial cracking. Combined with high resolution imaging system, DIC was applied to detect the initiation and extending of cracks. The proposed experimental method provides an essential routine in studying the fracture mechanism of all ceramic crowns under either static or fatigue occlusal loads.