Institute for Clinical Performance of Biomaterials, Seoul, Korea.
J Appl Oral Sci. 2011 Apr;19(2):154-60. doi: 10.1590/s1678-77572011000200012.
Indirect resin composites are generally regarded to have better color stability than direct resin composites since they possess higher conversion degree.
The present study aimed at comparing the changes in color (ΔE) and color coordinates (ΔL, Δa and Δb) of one direct (Estelite Sigma: 16 shades) and 2 indirect resin composites (BelleGlass NG: 16 shades; Sinfony: 26 shades) after thermocycling.
Resins were packed into a mold and light cured; post-curing was performed on indirect resins. Changes in color and color coordinates of 1-mm-thick specimens were determined after 5,000 cycles of thermocycling on a spectrophotometer.
ΔE values were in the range of 0.3 to 1.2 units for direct resins, and 0.3 to 1.5 units for indirect resins, which were clinically acceptable (ΔE<3.3). Based on t-test, ΔE values were not significantly different by the type of resins (p>0.05), while ΔL, Δa and Δb values were significantly different by the type of resins (p<0.05). For indirect resins, ΔE values were influenced by the brand, shade group and shade designation based on three-way ANOVA (p<0.05).
Direct and indirect resin composites showed similar color stability after 5,000 cycles of thermocycling; however, their changes in the color coordinates were different.
间接树脂复合材料通常被认为比直接树脂复合材料具有更好的颜色稳定性，因为它们具有更高的转化率。
本研究旨在比较 1 种直接（Estelite Sigma：16 种色调）和 2 种间接树脂复合材料（BelleGlass NG：16 种色调；Sinfony：26 种色调）在热循环后的颜色变化（ΔE）和颜色坐标（ΔL、Δa 和 Δb）。
将树脂填充到模具中并进行光固化；对间接树脂进行后固化。在分光光度计上进行 5000 次热循环后，测定 1mm 厚试件的颜色和颜色坐标变化。
直接树脂的ΔE 值在 0.3 到 1.2 单位之间，间接树脂的ΔE 值在 0.3 到 1.5 单位之间，均在临床可接受范围内（ΔE<3.3）。基于 t 检验，树脂类型对ΔE 值没有显著影响（p>0.05），而对ΔL、Δa 和 Δb 值有显著影响（p<0.05）。对于间接树脂，基于三因素方差分析，品牌、色调组和色调标记对ΔE 值有影响（p<0.05）。
直接和间接树脂复合材料在经过 5000 次热循环后表现出相似的颜色稳定性，但它们的颜色坐标变化不同。
