Evaluation of Some Mechanical and Optical Properties of Zirconia and Lithium Disilicate Materials After Hydrothermal Aging
Author(s): Zakariya Mohammed Al-Saffar* and Ahmed Asim Al-Ali
Abstract
Background: Dental ceramics have become a very popular material for the manufacturing of fixed dental prosthetics, a new manufactural technique was introduce recently , for construction of new zirconia blank that consist of two generation of zirconia in order to get the benefit of both generation to get more durable an esthetic restoration. Aims of the study: Evaluate the effects of hydrothermal aging on the flexural strength and translucency for tow type of zirconia and lithium disilicate, and to compare them with each other
Materials and methods: Forty five samples have been prepared from tow type of zirconia (ZirCAD MtMulti (4Y-5Y); ZirCAD Prime (3Y-5Y)) and lithium disilicate (IPS e.max CAD HT). Ten samples was used to test flexural strength form each type dental ceramic (half of them before aging and half after aging); five samples used to test translucency before and after aging. Aging was performed by using autoclave for 7.5 hours at 1340C and 0.2 bar pressure. Data were analyzed using paired t-test; independent t-test and One Way ANOVA Duncan’s tests at 5% level of significance also performed.
Results: There is No statically significant difference on flexural strength and significantly decrease on the translucency of both type of zirconia and lithium disilicate after hydrothermal aging. ZirCAD MtMulti had intermediate flexural strength and translucency parameter between ZirCAD Prime and IPS e.max CAD HT before and after aging.
Conclusion: Hydrothermal aging had No effect on flexural strength, and decrease the translucency parameter for all dental ceramic. Lithium disilicate had the lowest flexural strength value and highest translucency. When yttria concentration increases the flexural strength decrease and translucency increase.