Optical and Mechanical Properties of Newly Developed Monolithic Multilayer Zirconia

Purpose: To evaluate the optical and mechanical properties of newly introduced monolithic multilayer zirconia with two types of monolithic zirconia.

Materials and methods: Three brands of monolithic zirconia were used in this study: Ceramill Zolid FX Multilayer (CZF), Prettau Anterior (PA), and Zenostar T (ZT). Translucency parameter (TP), contrast ratio (CR), flexural strength, fracture toughness, hardness, brittleness index, and microstructures were assessed. Data were analyzed using one-way ANOVA and Tukey's test. The statistical significance was set at p < 0.05. A Weibull analysis was conducted on the flexural strength data.

Results: CZF revealed significantly higher TP and lower CR compared with PA and ZT monolithic zirconia (p < 0.05). ZT showed higher flexural strength and fracture toughness compared with CZF and PA (p < 0.001). On the other hand, CZF revealed significantly higher hardness values compared with PA and ZT (p < 0.001). CZF and PA revealed higher brittleness index than ZT monolithic zirconia (p < 0.001). ZT showed small grain microstructure while CZF and PA showed larger grains. ZT had a higher characteristic strength (σ₀ ), Weibull modulus (m), and a lower probability of failure compared with CZF and PA.

Conclusions: The optical and mechanical properties of the tested monolithic zirconia are material dependent. Fully stabilized monolithic zirconia materials (CZF and PA) are relatively more translucent than partially stabilized zirconia (ZT).