lllllllullu Acta Orthop Scand 1988;59(4):403-409 Effects of preparation techniques on the porosity of acrylic cements

' F i n v e s t i g a t e d four acrylic cement preparation techniques for their effects on cement porosity: hand mixing, pressurization in a pneumatic pistol, centrifugation, and vacuum mixing. All the techniques were tested on three types of cement with different viscosity characteristics. The best results were obtained with vacuum mixing using a newly designed experimental system, yielding porosity reductions of 60-80 percent relative to hand mixing. Vacuum mixing with a commercial system was also effective, but to a somewhat lesser extent. Pressurization and centrifugation had no substantial effect on the overall porosity. Centrifugation led to considerable nonuniformity in the distribution of pores and additives. The porosity of acrylic cement is important for its fatigue strength and depends, among other things, on the preparation technique. We have deter-mined the effects of four different techniques on the porosity of three cements with different vis-cosity characteristics in the curing phase. Material and methods Cylindric test bar