TITLE:
Effect of Thermocycle Aging on Color Stability of Monolithic Zirconia
AUTHORS:
Merve Koseoglu, Berkman Albayrak, Pinar Gül, Funda Bayindir
KEYWORDS:
Monolithic Zirconia, Color, Translucency, Thermocycling
JOURNAL NAME:
Open Journal of Stomatology,
Vol.9 No.3,
March
18,
2019
ABSTRACT: Background: The color stability of dental restorative materials is important for
long-term clinical success. Objectives: The objective of this study was to examine
the effect of thermocycling on the color and translucency stability of
monolithic zirconia. Materials and
methods: A total of 80 disc-shaped specimens (1 cm diameter) were produced from
monolithic zirconia material, Katana High Translucent (Kuraray Noritake Dental,
Kurashiki, Japan). The specimens were prepared in four different thicknesses:
0.5 mm, 1 mm, 1.5 mm and 2 mm. Before thermocycling, color measurements of the
specimens were made by a spectrophotometer (Spectro Shade TM MICRO; MHT Optic
Research AG, Milan, Italy). After the thermal aging procedure, the color
measurement was repeated. Data obtained from the study were analyzed with descriptive statistics, correlation analysis,
one-way ANOVA and Tukey’s tests. Results: After thermocycling, the L*, a*, b* values decreased at all thicknesses. The maximum change in the L*, a*
and b* values was observed in
0.5-mm-thick specimens, while the least change was observed in 2-mm-thick specimens. The amount of color change in the specimens after thermocycling was
found to be the highest in 0.5-mm-thick specimens (ΔE = 0.91 ± 0.02), and the lowest in 2-mm-thick specimens (ΔE = 0.85 ± 0.01). While a statistically
significant color change (ΔE) was
observed in 0.5-mm-thick specimens (p E) was
observed (p > 0.05) in 1-mm, 1.5-mm, and 2-mm-thick specimens. After thermocycling, the
translucency parameter (TP) values decreased at all
thicknesses. The highest change in the TP values was observed in 0.5-mm-thickspecimens
(1.09 ± 0.03), while the lowest change was observed in 2-mm-thickspecimens
(0.40 ± 0.04). While a statistically significant change in the TP values was observed in
0.5-mm-thick specimens (p 0.05). Conclusion: Although the color
and translucency values after thermocycling exhibited statistically significant
changes in the 0.5 mm thickness group, a statistically significant difference
was not observed in the other thickness groups.