Effect of mixing technique on the properties of acrylic bone-cement - A comparison of syringe and bowl mixing systems

Syringe mixing systems have been introduced, but few data exist regarding t he mechanical performance of cement they produce. We compared the propertie s of polymethyl methacrylate cement produced by these systems with that pro duced by a multiaxial bowl. Mixtures of cement were prepared using the Opti vac, Cemvac, and Summit syringes and the Summit bowl. The mixtures were cur ed in molds to create casts that were radiographed and analyzed for void co ntent, then cut into strips, weighed, measured, and tested to failure in 4- point bending. Syringe-mixed cement was of greater density, bending modulus , and bending strength than bowl-mixed cement (Mann-Whitney, P < .01) and c ontained fewer microvoids and macrovoids (Mann-Whitney, P < .01). No signif icant differences between the syringes were found for these variables (Krus kall-Wallis, P > .05).