Influence of translucence/opacity and shade in the flexural strength of lithium disilicate ceramics.

BACKGROUND

Lithium disilicate ceramic system consists of glass ceramic ingots with different grades of translucence which may influence its flexural strength.

AIMS

To assess the three-point flexural strength of the different lithium disilicate-based ceramic ingots (IPS e.max Press/Ivoclar Vivadent) with different levels of translucence and shade.

MATERIALS AND METHODS

Six groups of ceramic ingots were selected to represent different levels of translucence and shade (HTA1, HTBL2, LTA2, LTB2, MO2, and HO). They measured 25 mm × 5 mm × 2 mm (n = 10), according to ISO 6872 specifications, and tested on a universal test machine (EMIC).

STATISTICAL ANALYSIS USED

A one-way analysis of variance (ANOVA) was used (α = 0.05).

RESULTS

The results (in MPa) were: HTA1 = 392.98; HTBL2 = 390.74; LTA2 = 390.46; LTB2 = 389.92; MO2 = 390.43; HO = 391.96. ANOVA showed no significant difference among groups (P = 0.1528).

CONCLUSIONS

Different levels of translucence, opacity and shade of ingots did not affect their mechanical strength, and the use of these ceramics should be guided by the esthetic demands of each clinical situation.