EFFECT OF AGING ON TRANSLUCENCY AND FLEXURAL STRENGTH OF DIFFERENT ZIRCONIA MATERIALS (AN IN-VITRO STUDY)

Abstract

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.