Study of Zirconia's ageing for applications in dentistry

Zirconia based materials have been widely used in construction of dental prosthesis because of their mechanical and aesthetical properties and a lot of money have been invested in their development, but no one of the producers considered the aging of zirconia. In this job have been demonstrated, with Raman spectroscopy, the low temperature degradation of zirconia and has been investigated the residual stress in zirconia-alumina composites at room temperature and in open-air after 8 years of aging, then have been investigated the phase trasformation of tetragonal zirconia into monocline form of pure zirconia and alumina-zirconia composites tested in water with a thermal fatigue cycle between 5°C and 55°C. A partial solution of the problem is proposed. Atomic Force Microsopy and Near-field Scanning Optical Microscopy techniques have been tested as method of investigation and validation of the results.