Abrisham S M, Fallah Tafti A, Kheirkhah S, Tavakkoli M A
Department of Prosthodontics, Yazd University of Medical Sciences, Yazd, Iran.
School of Dentistry, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
J Dent Biomater. 2017 Mar;4(1):367-372.
Recent clinical results for Zirconia all-ceramic restorations have revealed that the fracture rate 6-15% of the Zirconia framework is so low and the core of Zirconia has high stability. However, chipping-off fractures of porcelain are the most common reason for failures of Zirconia in the fixed partial dentures.
The purpose of this study was to compare the shear bond strength (SBS) of porcelain in the porcelain fused to metal and all-ceramic crowns with Zirconia core.
Two groups were selected: porcelain fused to metal (PFM) and porcelain fused to Zirconia (PFZ) (n = 30).In the PFM group, a wax model (10 × 10 × 10mm)was used to cast metal base (Ni_Cr alloy). In the PFZ group, an acrylic cubic model (10 × 10 × 10mm) was made as Zirconia model for scanning.15 cubic Zirconia samples were milled by CAD-CAM. The procedure of porcelain veneering was conducted by the conventional layering technique up to 2 mm thickness (2.5 × 2.5 × 2 mm). All specimens were stored in water for 48 hrs. Thermal cycling was conducted for 20000 cycles between 55°C and 5ºC alternatively for 30s.All samples were mounted in acrylic resin and the SBS test was performed, using a universal testing machine. The analysis of data was performed at a significance level of 0.05 using Kolmogorov-Smirnov and Mann-Whitney U-test.
Mean of SBS in PFM and PFZ was 24.57 and 20.88, respectively. The results of Mann-Whitney test showed that there was no statistically significant difference between the two groups of porcelain fused to metal and Zirconia in item shear bond strength ( = 0.455).
There was no significant difference between the two groups of PFM and PFZ in the item SBS.
氧化锆全瓷修复体的近期临床结果显示，氧化锆框架6%-15%的骨折率非常低，且氧化锆核心具有高稳定性。然而，瓷崩裂骨折是固定局部义齿中氧化锆修复失败的最常见原因。
本研究的目的是比较烤瓷熔附金属全冠和氧化锆核全瓷冠中瓷的剪切粘结强度（SBS）。
选取两组：烤瓷熔附金属（PFM）组和烤瓷熔附氧化锆（PFZ）组（n = 30）。在PFM组中，使用蜡型（10×10×10mm）铸造金属基底（镍铬合金）。在PFZ组中，制作丙烯酸立方模型（10×10×10mm）作为氧化锆模型进行扫描。通过CAD-CAM铣削15个立方氧化锆样本。采用传统分层技术进行瓷贴面操作，厚度达2mm（2.5×2.5×2mm）。所有标本在水中储存48小时。在55°C和5°C之间交替进行20000次热循环，每次30秒。将所有样本安装在丙烯酸树脂中，并使用万能试验机进行SBS测试。使用Kolmogorov-Smirnov和Mann-Whitney U检验在显著性水平0.05下进行数据分析。
PFM组和PFZ组的SBS平均值分别为24.57和20.88。Mann-Whitney检验结果显示，烤瓷熔附金属组和氧化锆组在剪切粘结强度方面无统计学显著差异（= 0.455）。
PFM组和PFZ组在SBS方面无显著差异。
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