Doctoral researcher, Department of Prosthodontics, School of Dentistry, University of Istanbul, Istanbul, Turkey.
Professor, Department of Prosthodontics, School of Dentistry, University of Istanbul, Istanbul, Turkey.
J Prosthet Dent. 2018 Feb;119(2):308.e1-308.e7. doi: 10.1016/j.prosdent.2017.08.013. Epub 2017 Nov 15.
The influences of coloring and sintering procedures on the optical and mechanical properties of monolithic zirconia have not been thoroughly investigated.
The purpose of this in vitro study was to investigate the effects of the coloring procedure and of varying final sintering temperatures on the translucency parameter (TP) and biaxial flexural strength (BFS) of monolithic zirconia.
Disk-shaped specimens (N=210) of 2 different monolithic zirconia brands (Vita YZ HT [VYZa]; Vita YZ HT A2 [VYZb]; Prettau Zirkonzahn [PZ]; Prettau Anterior Zirkonzahn [PZA]) with a diameter of 15 mm and a thickness of 1.0 ±0.05 mm were prepared. Half of the specimens prepared from noncolored blocks (VYZa, PZ, and PZA) received coloring liquid application. Then, the specimens were divided into 3 subgroups (n=10) according to the final sintering temperatures (1350°C, 1450°C, and 1600°C). The TP was determined by using a reflection spectrophotometer, and the BFS was tested with the piston-on-3-ball method in a universal testing machine. Data were statistically analyzed by multivariate multiple regression and Bonferroni tests (α=.05).
Significant differences were obtained among the groups based on the results of the TP and BFS (P<.05). The TP was affected by the changes in final sintering temperature. The varying final sintering temperatures demonstrated no significant effect on the BFS, except in group PZ (noncolored) that produced lower BFS when sintered at 1350°C than the subgroups sintered at 1450°C and 1600°C (P<.05). Coloring liquid application significantly decreased the TP of VYZa (sintered at 1350°C) but produced no significant effect on the groups PZ and PZA. Additionally, the coloring procedure had no significant effect on the BFS of tested materials (VYZa, PZ, and PZA) (P>.05).
Increased sintering temperature leads to increased translucency with minimal impact on the BFS. The coloring procedure should be considered at the time of material selection to avoid possible reduction in translucency.
着色和烧结程序对整体氧化锆的光学和机械性能的影响尚未得到彻底研究。
本体外研究的目的是调查着色程序和不同最终烧结温度对整体氧化锆的透光率参数（TP）和双轴弯曲强度（BFS）的影响。
制备了 2 种不同的整体氧化锆品牌（Vita YZ HT [VYZa]； Vita YZ HT A2 [VYZb]；Prettau Zirkonzahn [PZ]；Prettau Anterior Zirkonzahn [PZA]）的直径为 15mm、厚度为 1.0±0.05mm 的圆盘状试件（N=210）。从非着色块（VYZa、PZ 和 PZA）制备的一半试件接受着色液应用。然后，根据最终烧结温度（1350°C、1450°C 和 1600°C）将试件分为 3 组（n=10）。使用反射分光光度计测定 TP，并用万能试验机的活塞-3 球法测定 BFS。使用多元多回归和 Bonferroni 检验（α=.05）对数据进行统计分析。
根据 TP 和 BFS 的结果，各组之间获得了显著差异（P<.05）。TP 受最终烧结温度变化的影响。不同的最终烧结温度对 BFS 没有显著影响，除了非着色的 PZ 组，当在 1350°C 烧结时，其 BFS 低于在 1450°C 和 1600°C 烧结的亚组（P<.05）。着色液应用显著降低了 VYZa（在 1350°C 烧结）的 TP，但对 PZ 和 PZA 组没有显著影响。此外，着色程序对测试材料（VYZa、PZ 和 PZA）的 BFS 没有显著影响（P>.05）。
升高的烧结温度会导致透光率增加，而对 BFS 的影响最小。在选择材料时应考虑着色程序，以避免透光率可能降低。
