Optical and Mechanical Properties of New Lithium Disilicate CAD-CAM Materials

Objectives: The purpose of this study was to compare the optical and mechanical properties of two new, inexpensive lithium disilicate materials to an established product on the market.
Methods: The following lithium disilicate materials were tested: Lodden (LOD), LD Medical Technology Co; BeautyZir (BZ), BeautyZir Technology Co; and IPS e.max CAD (EMAX), Ivoclar. Optical properties: Ten specimens (2mm thick) were sectioned from the blocks for each group. After crystallization and polishing, translucency (TP) and opalescence (OP) parameters were obtained with a dental spectrophotometer (Easyshade V, VITA). Mechanical properties: Thirty (4mm x 1.3mm x 17mm) beams were sectioned from the blocks for each group. After crystallization and polishing, flexural strength (FS) and flexural modulus (FM) were determined using fifteen specimens per group with a 3-point bend test using a universal testing machine (ElectroPuls E3000, Instron). Flexural fatigue strength (FFS) was determined with the remaining 15 specimens from each group using the staircase method (100,000 cycles/20 Hz). Data were analyzed with one-way ANOVA and Tukey’s post hoc test (α=0.05).
Results: Significant differences were found between the groups for TP, OP, and FM (p<0.05). See table below. Both LOD and BZ had significantly greater TP and OP compared to EMAX. There was no significant difference in FS and FFS between any of the materials. EMAX and LOD had greater FM than BZ.
Conclusions: The inexpensive lithium disilicate CAD-CAM material, Lodden, had better optical properties and similar mechanical properties to the established lithium disilicate material, IPS e.max CAD.