Improvement of the mechanical properties of acrylic bone cements by substitution of the radio-opaque agent.

Acrylic bone cements become radio-opaque by the addition of an inorganic compound, commonly BaSO4 or ZrO2. However, the use of these additives has some negative effects such as loss of mechanical properties, risk of release and bone resorption. The use of the monomer 2,5-diiodo-8-quinolyl methacrylate (IHQM), which shows adequate polymerization and radio-opacity properties, is proposed as a new X-ray opaque, methacrylate iodine-containing agent. The aim of this study is to determine the effect of this new radio-opaque agent on the mechanical properties of acrylic bone cements. The addition of the iodine-containing methacrylate provides a statistically significant increase in the tensile strength, fracture toughness and ductility, with respect to the barium sulphate-containing cement. This effect can be attributed to the fact that the use of a radio-opaque monomer eliminates the porosity associated with the barium sulfate particles, which show no adhesion to the matrix. However, some reinforcing effect must also be attributed to the iodine-containing monomer, since the tensile and fracture toughness values reached are even higher than those shown by the radiolucent cement. Copyright 1999 Kluwer Academic Publishers