Statement of problem

The optical properties of esthetic computer-aided design and computer-aided manufacturing (CAD-CAM) materials can change depending on the clinical situation. Studies that compare esthetic CAD-CAM materials based on their optical properties are lacking.

Purpose

The purpose of this in vitro study was to evaluate the optical properties of esthetic CAD-CAM specimens after ultraviolet (UV) aging based on the type and thickness of the material.

Material and methods

In total, 240 plate-shaped specimens (14×12×1 mm and 14×12×2 mm) of a nanohybrid composite resin (Tetric CAD), a fine-structure feldspathic ceramic (Vitablocs Mark II), 2 different glass-ceramics (IPS Empress CAD and IPS e.max CAD), a zirconia-reinforced lithium silicate glass-ceramic (Celtra Duo), a polymer-infiltrated ceramic network (Vita Enamic), and 2 different resin nanoceramics (Cerasmart and Lava Ultimate) were fabricated (n=15). The optical parameters were analyzed by spectrophotometry before and after UV aging. The brightness (L∗), red green (a∗), yellow-blue (b∗), chroma (Ch), and hue (h) were measured, and the color difference (ΔE₀₀) values were calculated. The translucency parameter (TP), total transmittance (Tt), and contrast ratio (CR) were also determined. Statistical analyses were performed with 1-way ANOVA, the Tukey honestly significant difference post hoc test, independent- and paired-samples t tests, and 2-way ANOVA (α=.05).

Results

Significant interactions were observed for the aging process, material type, and thickness for all optical parameters (P<.05). L∗, TP, and Tt had lower values, while CR had higher values for the aging group than that of the control group (P<.05). The h, TP, and Tt values were higher, whereas the b∗ and CR values were lower for the 1-mm group than those of the 2-mm group (P<.05). The highest ΔE₀₀ value was found in the Lava Ultimate 1-mm group (ΔE₀₀=3.21) and 2-mm group (ΔE₀₀=2.42). The lowest ΔE₀₀ value was found in the Vitablocs Mark II 1-mm group (ΔE₀₀=0.31). The highest TP and Tt and the lowest CR values were observed for Tetric CAD; the lowest TP and Tt, and the highest CR values were noted in Celtra Duo (P<.05).

Conclusions

The optical properties of the CAD-CAM specimens were affected by the aging process, material type, and thickness, and the color stability was clinically applicable in all CAD-CAM materials except groups Lava Ultimate and Cerasmart(ΔE₀₀<2.25). Resin nanoceramics exhibited the greatest color changes after UV aging, and a 2-mm thickness is recommended to ensure acceptable color stability. The zirconia-reinforced lithium silicate glass-ceramic was the most opaque, with a 1-mm thickness providing increased translucency.

中文翻译：

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美学修复材料对紫外线老化反应的评价

问题陈述

美学计算机辅助设计和计算机辅助制造 (CAD-CAM) 材料的光学特性可以根据临床情况而改变。缺乏根据光学特性比较美观的 CAD-CAM 材料的研究。

目的

这项体外研究的目的是根据材料的类型和厚度评估经过紫外线 (UV) 老化后的美观 CAD-CAM 样品的光学特性。

材料与方法

总共有 240 个板状样品（14×12×1 毫米和 14×12×2 毫米）的纳米混合复合树脂 (Tetric CAD)、精细结构的长石陶瓷 (Vitablocs Mark II)、2 种不同的玻璃陶瓷（IPS Empress CAD 和 IPS e.max CAD）、氧化锆增强的硅酸锂玻璃陶瓷（Celtra Duo）、聚合物渗透陶瓷网络（Vita Enamic）和 2 种不同的树脂纳米陶瓷（Cerasmart 和 Lava Ultimate） (n=15)。通过分光光度法分析紫外老化前后的光学参数。测量了亮度 (L∗)、红绿 (a∗)、黄蓝 (b∗)、色度 (Ch) 和色调 (h)，以及色差 (ΔE ₀₀) 值进行计算。还确定了半透明参数 (TP)、总透光率 (Tt) 和对比度 (CR)。使用 1 向方差分析、Tukey 诚实显着差异事后检验、独立和配对样本t检验以及 2 向方差分析 (α=.05) 进行统计分析。

结果

在老化过程、材料类型和所有光学参数的厚度方面都观察到了显着的相互作用 ( P <.05)。L∗、TP 和 Tt 值较低，而老化组的 CR 值高于对照组（P <.05）。h、TP 和 Tt 值较高，而 1-mm 组的 b*和 CR 值低于 2-mm 组（P <.05）。在 Lava Ultimate 1-mm 组（ΔE ₀₀ =3.21）和 2-mm 组（ΔE ₀₀ =2.42）中发现了最高的 ΔE ₀₀值。在 Vitablocs Mark II 1-mm 组中发现了最低的 ΔE ₀₀值（ΔE ₀₀=0.31)。Tetric CAD 的 TP 和 Tt 最高，CR 值最低；Celtra Duo 的 TP 和 Tt 最低，CR 值最高（P <.05）。

结论

CAD-CAM 样品的光学性能受老化过程、材料类型和厚度的影响，颜色稳定性临床适用于除 Lava Ultimate 和 Cerasmart 组外的所有 CAD-CAM 材料（ΔE ₀₀ <2.25）。树脂纳米陶瓷在紫外线老化后表现出最大的颜色变化，建议使用 2 毫米的厚度以确保可接受的颜色稳定性。氧化锆增强的硅酸锂玻璃陶瓷是最不透明的，厚度为 1 毫米，增加了半透明度。