Effect of Multilayering Technology on Flexural Strength of Translucent Zirconia: Pilot Study

Objectives: To evaluate the effect of multilayer technology on flexural strength of multilayer translucent zirconia discs.
Methods: In this study, the 5Y TZP zirconia disc was sectioned in two different directions (Fig 1); vertical sections including all the layers (multi-layer group) and horizontal sections including only one layer (single-layer group). 25 mm zirconia disc (Cercon XT MultiLayer) was used to section and fabricate bar specimens with 20 mm x 1.5 mm x 1.5 mm dimensions (n=10 per group). Specimens were polished using 1200 grit polishing paper. The flexural strength was measured using the Instron 5566 universal test machine in a three-point-bending design (Fig 2) with crosshead speed of 0.5 mm/min. Data Analysis was performed using independent sample t-test with significance level set at 0.05.
Results: Flexural strength of the multilayer group was 586.58 MPa and single layer groups was 609.51 MPa. Data were distributed normally according to Kolmogrov-Smirnov test. According to independent sample T-test, no statistically significant difference was found between the two groups (P-value=0.640).
Conclusions: Based on the current findings, multilayering technology implemented in the tested 5Y TZP zirconia disc had no effect on the flexural strength and it may be concluded that different layers are attached to each other cohesively.