Effect of sintering temperature on translucency parameter of zirconia blocks

Abstract

Background: The main drawbacks of zirconia are its high refractive index and opacity. This
study aimed to assess the effect of sintering temperature on the translucency of Ivoclar e. max
ZirCAD (IEZ), and White Peaks Symphony (WPS) zirconia blocks.
Materials and Methods: In this in vitro experimental study, 30 IEZ and 30 WPS zirconia blocks
measuring 10 mm × 10 mm × 1 mm were prepared and underwent sintering in three subgroups at
1440°C, 1500°C, and 1530°C. The specimens were then photographed against a black and a white
background with a standard digital camera. The L*, a*, and b* color parameters were measured using
Adobe Photoshop software, and translucency was calculated. Data were analyzed using one‑way
ANOVA and Tukey’s test (P < 0.05).
Results: In both the IEZ and WPS groups, the maximum and minimum translucency parameters were
recorded in 1530°C and 1440°C subgroups, respectively. The difference in the mean translucency was
significant among the three subgroups of each zirconia group (P < 0.001). The mean translucency of
WPS zirconia was significantly higher than that of IEZ zirconia (P < 0.01), and maximum difference
was noted at 1500°C sintering temperature.
Conclusion: Increasing the sintering temperature from 1440°C to 1530°C can significantly increase
the translucency of IEZ and WPS zirconia blocks, and can be considered to improve the quality of
zirconia restorations.
Key Words: Ceramics, refractometry, yttria‑stabilized tetragonal zirconia