Microstructure of alumina- and alumina/zirconia-glass infiltrated dental ceramics

The microstructure and the fracture behavior of four dental ceramics In-Ceram Alumina and In-Ceram Zirconia (slip and block) were investigated with SEM in order to study the differences existing among the four materials and correlate them with apparently contradictory previous mechanical studies. Microstructural observations indicate, In-Ceram Alumina slip and block to be two different materials and a dissimilar mechanical behavior is also expected. It is postulated that the presence of a low modulus glassy phase and a significant porosity, counteract the transformation toughening potential of the tetragonal zirconia in In-Ceram Zirconia.