Department of Prosthodontics, Faculty of Dentistry, Shiraz University of Medical Sciences, Shiraz, Fars, Iran.
Student Research Committee, Faculty of Dentistry, Shiraz University of Medical Sciences, Shiraz, Fars, Iran.
PLoS One. 2024 Nov 14;19(11):e0313645. doi: 10.1371/journal.pone.0313645. eCollection 2024.
Achieving the aesthetic standards in tooth-colored restorative materials requires close attention to their color, translucency, and resistance to discoloration. This study aimed to evaluate the effect of sintering temperature on color stability and translucency in zirconia systems with low, high, and ultra-high translucencies.
This experimental study was conducted on 60 zirconia disks with low, high and ultra-high translucencies (n = 20 per group), each group divided into subgroups to be sintered at either 1450°C or 1550°C (n = 10 per subgroup). Baseline color and translucency parameters were measured, the specimens were then immersed in coffee solution for 30 days, and the measurements were repeated post-immersion. Changes in color (ΔE) and translucency (ΔTP) were calculated via CIELAB formula and compared by using two-way ANOVA and Tukey's post hoc test (α = 0.05).
Results of two-way ANOVA showed that the ΔE was significantly different among the three zirconia translucencies (P<0.001), but no significant difference was found between the two sintering temperatures (P = 0.712). Additionally, the interaction between zirconia type and sintering temperature was not statistically significant for ΔE (P = 0.264). The low-translucency group showed significantly greater ΔE than the high-translucency and ultra-high-translucency groups (P<0.05), while the high- and ultra-high-translucency groups were not significantly different in this regard (P>0.05). Regarding the ΔTP, two-way ANOVA showed that the difference was not statistically significant either among the three zirconia types (P = 0.4430) or between the two sintering temperatures (P = 0.4544). Nor was the interaction between zirconia type and sintering temperature statistically significant (P = 0.5505).
It was concluded that sintering temperature had no effect on color and translucency changes after immersion in coffee. Whereas zirconia type significantly affected the color changes after immersion in coffee; with the higher-translucency zirconia types being significantly more color-stable than the low-translucency zirconia.
要达到牙色修复材料的美学标准，需要密切关注其颜色、半透明度和抗变色性。本研究旨在评估烧结温度对低、高和超高透明度氧化锆系统的颜色稳定性和半透明度的影响。
本实验研究采用低、高和超高透明度（每组 20 个，n = 60 个）的 60 个氧化锆圆盘，将每个组分为在 1450°C 或 1550°C 下烧结的亚组（n = 10 个）。测量基线颜色和半透明度参数，然后将标本浸入咖啡溶液中 30 天，再进行测量。通过 CIELAB 公式计算颜色变化（ΔE）和半透明度变化（ΔTP），并使用双向方差分析和 Tukey 事后检验进行比较（α = 0.05）。
双向方差分析结果表明，三种氧化锆半透明度之间的 ΔE 差异显著（P<0.001），但烧结温度之间无显著差异（P = 0.712）。此外，氧化锆类型和烧结温度之间的相互作用对于 ΔE 无统计学意义（P = 0.264）。低半透明度组的 ΔE 显著大于高半透明度和超高半透明度组（P<0.05），而高半透明度和超高半透明度组之间无显著差异（P>0.05）。关于 ΔTP，双向方差分析表明，三种氧化锆类型之间（P = 0.4430）或两种烧结温度之间（P = 0.4544）差异均无统计学意义。氧化锆类型和烧结温度之间的相互作用也无统计学意义（P = 0.5505）。
结论是，在咖啡浸泡后，烧结温度对颜色和半透明度变化没有影响。然而，氧化锆类型显著影响咖啡浸泡后的颜色变化，高透明度氧化锆类型比低透明度氧化锆类型的颜色稳定性更高。
