Peregrina A, Schorr B L
Department of Fixed Prosthodontics and Occlusion, University of Missouri-Kansas City, School of Dentristry.
J Prosthet Dent. 1990 Aug;64(2):162-6. doi: 10.1016/0022-3913(90)90172-9.
This study tested the effect of bsprue design on internal porosity of a silver-frees high-palladium alloy. The designs evaluated consisted of: (1) a cylindrical sprue, (2) a cylindrical sprue with a reservoir, and (3) cylindrical sprue with a constriction at the point of attachment with the pattern. Ten identical complete crowns were made with each sprue design. The cast crowns were embedded in epoxy resin, sectioned, and polished. A total of six sites for each sample were analyzing computer. The mean amount of internal porosity from all analyzed sites for each sprue design was calculated as a percent site porosity per total site and differences between the experimental sites and groups tested. The analysis of variance found no significant differences among the sprues and no significant interaction, but determined a significant difference (p less than 0.05) among the sites analyzed. Tukey's studentized range test showed that the sprue contained a significantly greater percentage of porosity than any of the other sites analyzed.
本研究测试了b型浇道设计对一种无银高钯合金内部气孔率的影响。所评估的设计包括：（1）圆柱形浇道，（2）带有储液器的圆柱形浇道，以及（3）在与铸型连接处有缩颈的圆柱形浇道。每种浇道设计制作了10个相同的全冠。将铸好的全冠嵌入环氧树脂中，切片并抛光。每个样本总共六个部位通过计算机进行分析。计算每种浇道设计所有分析部位的内部气孔平均量，以占总部位的气孔百分比表示，并测试实验组部位之间的差异。方差分析发现浇道之间无显著差异，也无显著交互作用，但确定所分析部位之间存在显著差异（p小于0.05）。图基氏学生化极差检验表明，浇道处的气孔百分比显著高于其他任何分析部位。
