Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Necmettin Erbakan University, Konya, Turkey.
J Prosthet Dent. 2022 May;127(5):801.e1-801.e8. doi: 10.1016/j.prosdent.2021.12.004. Epub 2022 Feb 10.
The use of monolithic zirconia for restorations has become popular. However, the effects of the coloring process and sintering procedure on the optical properties of monolithic zirconia remain unclear.
The purpose of this in vitro study was to evaluate the effects of the different sintering protocols and dipping times on the CIELab color parameters, color difference (ΔE), translucency parameter (TP), opalescence parameter (OP), and contrast ratio (CR) of monolithic zirconia.
One hundred and fifty monolithic zirconia specimens were prepared and divided into 5 groups according to different dipping times in A2 shade coloring liquid: no immersion (D0), 3 minutes (D3), 5 minutes (D5), 7 minutes (D7), and 9 minutes (D9). The specimens were further divided into 3 subgroups according to different sintering protocols (n=10): classic (C); speed (S); and super-speed sintering (SS). The CIE L∗a∗b∗ values, ΔE, TP, OP, and CR values were determined with a spectrophotometer. The data were analyzed with 2-way ANOVA and Bonferroni post hoc tests (α=.05).
The effects of the sintering protocol, dipping time, and interaction of the sintering protocol and dipping time were significant for the L∗, a∗, b∗, ΔE, TP, OP, and CR parameters (P<.001). The ΔE values of the SS groups were significantly higher than those of the C and S groups for all the dipping times assessed. However, only the CD3 and CD5 groups had ΔE values below the acceptability threshold (<1.8). Coloring significantly reduced TP values and significantly increased OP and CR values in the colored groups compared with those in the D0 groups. The C and S protocols for different dipping times showed similar optical properties in TP, OP, CR, and ΔE (excluding the D0 and D9 groups) compared with the SS protocol.
Different sintering protocols combined with various dipping times significantly affected the optical properties of monolithic zirconia. However, C and S sintering with a 3-minute and 5-minute coloring process yielded more favorable optical results than SS sintering and prolonged dipping times.
整体式氧化锆的应用已变得流行。然而，着色工艺和烧结程序对整体式氧化锆光学性能的影响仍不清楚。
本体外研究的目的是评估不同烧结方案和浸泡时间对整体式氧化锆的 CIELab 颜色参数、色差（ΔE）、半透明度参数（TP）、乳光参数（OP）和对比率（CR）的影响。
制备 150 个整体式氧化锆样本，并根据 A2 遮色液的不同浸泡时间分为 5 组：无浸泡（D0）、3 分钟（D3）、5 分钟（D5）、7 分钟（D7）和 9 分钟（D9）。根据不同的烧结方案（n=10）将样本进一步分为 3 个亚组：常规（C）、快速（S）和超快速烧结（SS）。使用分光光度计测定 CIE Lab*值、ΔE、TP、OP 和 CR 值。采用双因素方差分析和 Bonferroni 事后检验（α=.05）对数据进行分析。
烧结方案、浸泡时间以及烧结方案和浸泡时间的相互作用对 L*、a*、b*、ΔE、TP、OP 和 CR 参数均有显著影响（P<.001）。对于所有评估的浸泡时间，SS 组的 ΔE 值均显著高于 C 组和 S 组。然而，只有 CD3 和 CD5 组的 ΔE 值低于可接受阈值（<1.8）。与 D0 组相比，着色组的 TP 值明显降低，OP 和 CR 值明显升高。对于不同浸泡时间的 C 和 S 方案，在 TP、OP、CR 和 ΔE 方面（不包括 D0 和 D9 组）与 SS 方案相比具有相似的光学性能。
不同的烧结方案结合不同的浸泡时间对整体式氧化锆的光学性能有显著影响。然而，C 和 S 烧结与 3 分钟和 5 分钟的着色工艺相比，SS 烧结和延长的浸泡时间产生了更理想的光学效果。
