Ghaffari Tahereh, Hamedirad Fahimeh, Ezzati Baharak
Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran ; Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
J Dent Res Dent Clin Dent Prospects. 2014 Fall;8(4):204-9. doi: 10.5681/joddd.2014.037. Epub 2014 Dec 3.
Background and aims. Polymethyl methacrylate, PMMA, is widely used in prosthodontics for fabrication of removable prostheses. This study was undertaken to investigate the effect of adding silver nanoparticles (AgNPs) to PMMA at 2% and 0.2% concentrations on compressive and tensile strengths of PMMA. Materials and methods. The silver nanoparticles were mixed with heat-cured acrylic resin in an amalgamator in two groups at 0.2 and 2 wt% of AgNPs. Eighteen 2×20×200-mm samples were prepared for tensile strength test, 12 samples containing silver nanoparticle and 6 samples for the control group. Another 18 cylindrical 25×38-mm samples were prepared for compressive strength test. Scanning electron microscopy was used to verify homogeneous distribution of particles. The powder was manually mixed with a resin monomer and then the mixture was properly blended. Before curing, the paste was packed into steel molds. After curing, the specimens were removed from the molds. One-way ANOVA was used for statistical analysis, followed by multiple comparison test (Scheffé's test). Results. This study showed that the mean compressive strength of PMMA reinforced with AgNPs was significantly higher than that of the unmodified PMMA (P<0.05). It was not statistically different between the two groups reinforced with AgNPs. The tensile strength was not significantly different between the 0.2% group and unmodified PMMA and it de-creased significantly after incorporation of 2% AgNPs (P<0.05). Conclusion. Based on the results and the desirable effect of nanoparticles of silver on improvement of compressive strength of PMMA, use of this material with proper concentration in the palatal area of maxillary acrylic resin dentures is recommended.
背景与目的。聚甲基丙烯酸甲酯（PMMA）在口腔修复学中广泛用于制作可摘义齿。本研究旨在探究以2%和0.2%的浓度向PMMA中添加银纳米颗粒（AgNPs）对PMMA抗压强度和拉伸强度的影响。材料与方法。将银纳米颗粒与热固化丙烯酸树脂在研磨机中混合，分为两组，AgNPs的含量分别为0.2 wt%和2 wt%。制备18个2×20×200 mm的样本用于拉伸强度测试，其中12个样本含有银纳米颗粒，6个样本作为对照组。另外制备18个25×38 mm的圆柱形样本用于抗压强度测试。使用扫描电子显微镜验证颗粒的均匀分布。将粉末与树脂单体手动混合，然后将混合物充分搅拌。固化前，将糊剂装入钢模具中。固化后，将试样从模具中取出。采用单因素方差分析进行统计分析，随后进行多重比较检验（Scheffé检验）。结果。本研究表明，用AgNPs增强的PMMA的平均抗压强度显著高于未改性的PMMA（P<0.05）。在两组用AgNPs增强的材料之间没有统计学差异。0.2%组与未改性PMMA之间的拉伸强度没有显著差异，而加入2% AgNPs后拉伸强度显著降低（P<0.05）。结论。基于这些结果以及银纳米颗粒对提高PMMA抗压强度的理想效果，建议在上颌丙烯酸树脂义齿的腭部区域使用适当浓度的这种材料。
