Specimens from each firing cycle (n=10) were then subjected to hydrothermal aging in an autoclave sterilizer for 10 or 20 hours to accelerate the LTD of Y-TZP.  Specimens without hydrothermal aging served as the control.  Hydrothermal aging increased the monoclinic phase, although increased hydrothermal aging time provided no additional effects.  Veneering firings did not enhance the influence of hydrothermal aging on phase transformation. 
THERM