Statement of Problem: Since ultra high translucent cubic zirconia was evolved in the market,
comparison were made with high translucent tetragonal zirconia regarding translucency and flexural
strength after thermal aging.
Aim of This Study : The aim of this study is to detect translucency and flexural strength
changes of two different zirconia materials before and after aging.
Material and Methods: Forty Zirconia samples (n=20) from each type (Cubic and Tetragonal
Zirconia) were prepared then autoclaved. The aging parameter was set to a temperature of 134 C°
and a pressure of 2 bar for 10 hours of aging. A spectrophotometer device was used for measurement
of translucency and contrast ratio of each group. Piston and three supporting balls test were used
for flexural strength test.
Results: The results showed that Zirconia type (regardless of aging) had a statistically
significant effect on mean translucent parameter and flexural strength. Aging had a statistically
significant effect on mean translucent parameter and flexural strength except for the cubic zirconia
which showed non-significant lower flexural strength after aging.
Conclusion: Aging (regardless of Zirconia type) had a statistically significant effect on mean
translucent parameter and flexural strength. Flexural strength of cubic zirconia was not significantly
affected by aging.
