The more translucent the material being processed is, the thicker the wall and edge have to be, due to the decreasing flexural strength. The patient's oral situation often does not allow for this, which is why these requirements are often not met against better knowledge. If this is the case, that the recommendations regarding wall and edge thicknesses are not observed, fractures and cracks can occur in the structure.
The incorrect use of ceramic firing can also lead to cracks, fissures or, more generally, to “chipping”. Zirconia is a poor conductor of heat, which is why this material has different requirements for ceramic firing than metal frameworks.