São Paulo State University, Department of Dental Materials and Prosthodontics, São José dos Campos, SP, Brazil.
Dent Mater. 2011 Sep;27(9):948-53. doi: 10.1016/j.dental.2011.05.009. Epub 2011 Jun 25.
To determine the effect of porcelain thickness and the application of a surface liner (SL) on the flexural strength (σ) of a ceramic system.
One hundred twenty bar-shaped specimens of yttria-stabilized zirconia-based ceramic were fabricated and randomly divided into two groups according to the application of SL: A - applied; B - not applied. The specimens were further divided according to the porcelain veneer thickness (n=20): 0-0.5mm; 1-1.0mm; 2-2.0mm. All specimens were tested in 3-point bending with the porcelain under tension. The maximum load was recorded at first sign of fracture, the σ was calculated and the mode of failure was determined. Data was statistically analyzed using one-way ANOVA, Tukey (α=0.05) and Weibull distribution.
The SL application had no effect (p=0.723) while the porcelain thickness had a significant effect (p=0.000) on the mean σ values. No significant differences in mean σ values were found with same porcelain thickness. A 0.5-mm thick porcelain layer (groups A0 and B0) showed greater mean σ values than other groups. The Weibull modulus (m) ranged from 6 (groups A1 and B2) to 9 (groups A0, A2 and B0). The predominant mode of failure for all groups was fracture initiation at the porcelain surface propagating to the ceramic interface.
The porcelain thickness influenced the mean σ values, but the SL had no significant effect on the flexural strength and the mode of failure of the ceramic system examined.
确定瓷层厚度和表面衬层（SL）的应用对陶瓷系统的弯曲强度（σ）的影响。
制备了 120 个氧化钇稳定氧化锆基陶瓷的条形试件，并根据 SL 的应用将其随机分为两组：A-应用；B-未应用。根据瓷贴面厚度（n=20）进一步将试件分为以下三组：0-0.5mm；1-1.0mm；2-2.0mm。所有试件均在三点弯曲下进行测试，瓷层受拉。在首次出现断裂迹象时记录最大载荷，计算σ值并确定失效模式。使用单向方差分析、Tukey（α=0.05）和威布尔分布对数据进行统计分析。
SL 的应用没有影响（p=0.723），而瓷层厚度对平均σ值有显著影响（p=0.000）。相同瓷层厚度下，平均σ值没有显著差异。0.5mm 厚的瓷层（A0 和 B0 组）显示出更高的平均σ值。威布尔模数（m）范围从 6（A1 和 B2 组）到 9（A0、A2 和 B0 组）。所有组的主要失效模式都是瓷层表面起始的断裂扩展到陶瓷界面。
瓷层厚度影响平均σ值，但 SL 对所研究的陶瓷系统的弯曲强度和失效模式没有显著影响。
