Flexural Strength of New High-translucent Zirconia and Lithium Disilicate Ceramics With Two Specimen Dimensions

Objectives: This in-vitro study measured and compared the flexural strength of new KATANA Zirconia Ultra Translucent (UT), KATANA Zirconia Super Translucent (ST), and IPS e.max Press lithium disilicate using 3-point bending test with two different span lengths (12 mm and 30 mm)
Methods: Specimens for all three groups were fabricated in two dimensions (n=10):
- 14 x 2 x 4 mm (span length 12 mm)
- 34 x 3 x 4 mm (span length 30 mm)

Flexural strength was measured in a 3-point bending fixture on 2 supports using a universal testing machine (Instron Model 4204, Instron Corp, Norwood, Mass) at a crosshead speed of 1.0 mm/min and load cell capacity of 1 kN was used. The flexural strength values [MPa] for the specimens were computed using standard formula. One-way ANOVA was applied for statistical analyses.
Results: Flexural strength values were significantly different among different material groups for both span lengths (P = <0.05). Flexural strength values ranked as follows; Katana ST > Katana UT > IPS e.max Press. (Table 1) The flexural strength values for different dimensions of the same material were not significantly different. (p<0.05)
Conclusions: High-translucent zirconia has higher flexural strength than lithium disilicate ceramic. Between the Katana zirconia groups, the ST demonstrate higher flexural strength than the UT. Specimen dimension does not affect flexural strength values.