Translucency of High-Translucency Monolithic Zirconium-Oxide Materials

Objectives: Manufacturers have reportedly developed less opaque monolithic zirconium-oxide materials to improve esthetics. The purpose of this study was to evaluate the translucency of recently marketed high-translucency monolithic zirconia materials.
Methods: Four monolithic zirconia materials in shade A2 (BruxZir Shaded-16, BruxZir High-Translucency (HT), Glidewell; Lava Plus, 3M/ESPE; inCoris TZI C, Sirona) were compared to a high-translucency, lithium-disilicate glass-ceramic material (e.max CAD HT, shade A2, Ivoclar). The materials were sectioned into 0.5, 1, 1.5, and 2mm thick specimens using a precision saw, polished and sintered according to the manufacturer’s instructions. Five specimens were prepared per thickness of material. Translucency parameter was calculated using a spectrophotometer (VITA Easyshade, Vident) that measured L*, a*, and b* values. Three measurements were made per specimen. Data were analyzed with ANOVA/Tukey’s with a Bonferroni correction (alpha=0.006).
Results: Significant differences in translucency parameter was found between groups based on material or thickness (p<0.006). See table below.
Conclusions: e.max CAD had significantly higher translucency than the other materials at each thickness. In general, the translucencies of the zirconia materials were fairly similar at each thickness. However, at clinically relevant thicknesses, 1mm of BruxZir Shaded 16 and InCoris TZI C were more translucent than Lava Plus and BruxZir HT, but similar in translucency to the 1.5mm-thick specimens of e.max CAD. Translucency significantly decreased for each material at each increase in thickness.