Department of Dentistry, Faculty of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Department of Geology, Faculty of Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece.
J Prosthodont Res. 2022 Jul 30;66(3):491-501. doi: 10.2186/jpr.JPR_D_21_00067. Epub 2021 Nov 30.
The investigation of zirconia core surface pretreatments on the flexural strength of bilayered zirconia ceramics before and after artificial accelerating aging.
Ninety bar-shaped specimens were manufactured from Yttria Stabilized Tetragonal Zirconia Polycrystal (Y-TZP) and divided in three groups depending on zirconia surface pretreatment before veneering: layering with liner, pretreatment with silane-containing gas flame (SGF) with the Silano-Pen device and alumina air-abrasion. Half of the veneered specimens in each group (n=15) underwent artificial accelerating aging. A 4-point bending test was performed to determine flexural strength. Three specimens from each group were further analyzed using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) before veneering and after fracture (aged and non-aged subgroups).
Alumina air-abrasion was correlated to increased phase transformation from tetragonal to monoclinic zirconia phase. Qualitative analysis revealed that with the majority of the specimens pretreated with the silane-containing gas flame, areas of the veneering material remained firmly attached to the zirconia core after flexural strength testing. There was no statistically significant difference on the flexural strength among the groups before or after aging. Artificial accelerating aging resulted in statistically significant higher flexural strength of the specimens after aging.
SGF pretreatment can be an acceptable and feasible alternative method before the veneering of Y-TZP zirconia as it presented slightly higher bond strength compared with alumina air-abrasion which was associated with higher tetragonal to monoclinic (t→m) phase transformation. Accelerating aging leads to an increase of the mechanical properties under in vitro conditions.
研究氧化锆核表面预处理对双层氧化锆陶瓷弯曲强度的影响，包括人工加速老化前后。
采用 Yttria Stabilized Tetragonal Zirconia Polycrystal（Y-TZP）制造 90 个条形样本，并根据 veneering 前氧化锆表面预处理的不同将其分为三组：层压用衬垫、Silano-Pen 设备用含硅烷气体火焰（SGF）预处理和氧化铝喷砂预处理。每组 veneered 样本的一半（n=15）经历人工加速老化。通过四点弯曲试验测定弯曲强度。每组的三个样本在 veneering 前和断裂后（老化和非老化亚组）使用扫描电子显微镜（SEM）、X 射线衍射（XRD）和傅里叶变换红外光谱（FTIR）进一步分析。
氧化铝喷砂与四方氧化锆相到单斜氧化锆相的相变增加有关。定性分析表明，用含硅烷气体火焰预处理的大多数样本，在弯曲强度测试后， veneering 材料的大部分仍牢固地附着在氧化锆核上。老化前后各组之间的弯曲强度没有统计学上的显著差异。人工加速老化导致老化后样本的弯曲强度有统计学上的显著提高。
在 veneering Y-TZP 氧化锆之前，SGF 预处理可以是一种可接受且可行的替代方法，因为与氧化铝喷砂相比，它的结合强度略高，而氧化铝喷砂与更高的四方到单斜（t→m）相变有关。加速老化导致体外条件下机械性能的提高。
