Department of Dental Materials and Prosthodontics, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Paulista State University, São José dos Campos, Brazil.
Department of Restorative Dentistry, São José dos Campos Dental School, Institute of Science and Technology, UNESP-Paulista State University, São José dos Campos, Brazil.
J Esthet Restor Dent. 2020 Jan;32(1):113-118. doi: 10.1111/jerd.12558. Epub 2019 Dec 19.
Evaluate the effect of staining and repeated firings on color, translucency and surface proprieties of CAD/CAM lithium disilicate (LD).
One hundred eighty LD discs were made (ISO 6872) and distributed in different groups (n = 20): control (CO)-no treatment; single-step characterization (SC)-crystallization and staining fired together; and double step characterization (DC)-crystallization and then staining. The samples were submitted to two, four, or six firings, resulting in nine groups: COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV, and DCVI. The color and translucency were measured by a reflectance spectrophotometer. Surface roughness (Ra) and Vickers nano-hardness were also measured. ANOVA and Tukey statistical tests were used (α = .05).
Only CO and DC demonstrated significant color alterations (ΔE > 1.8). SC and DC did not show changes in translucency by the number of firings (P > .05); however, for CO (P = .02) these values increased. Nano-hardness was similar in all groups (P > .05). Ra values indicated differences due to the type of characterization (SC presented the highest values) and number of firings (CO and DC groups) (P < .01).
SC promoted color, translucency, and roughness stability after repeated firings.
The single characterization technic in CAD/CAM lithium disilicate presents good color, translucency, and hardness stability, which promote predictable results to monolithic restoration.
评估染色和重复烧制对 CAD/CAM 二硅酸锂（LD）颜色、半透明度和表面性能的影响。
制作了 180 个 LD 圆盘（ISO 6872），并分为不同组（n = 20）：对照组（CO）-无处理；单步特征化（SC）-一起结晶和染色；双步特征化（DC）-先结晶后染色。将样品进行两次、四次或六次烧制，共产生九组：COII、COIV、COVI、SCII、SCIV、SCVI、DCII、DCIV 和 DCVI。用反射分光光度计测量颜色和半透明度。还测量了表面粗糙度（Ra）和维氏纳米硬度。采用方差分析和 Tukey 统计检验（α = 0.05）。
只有 CO 和 DC 表现出明显的颜色变化（ΔE > 1.8）。SC 和 DC 经过多次烧制后半透明度没有变化（P > 0.05）；然而，对于 CO（P = 0.02），这些值增加了。所有组的纳米硬度都相似（P > 0.05）。Ra 值因特征化类型（SC 呈现最高值）和烧制次数（CO 和 DC 组）而存在差异（P < 0.01）。
SC 在重复烧制后可稳定颜色、半透明度和粗糙度。
CAD/CAM 二硅酸锂的单特征化技术具有良好的颜色、半透明度和硬度稳定性，可预测整体修复的结果。
