Acrylic bone cement

Local biocompatibility

Although polymerized polymethylmethacrylate is a biocompatible material, it is not biocompatible during the brief time it takes to set, during which it releases 130 calories/gram and can cause a rise in temperature up to 120 °C. This temperature rise can be reduced by various techniques, although the thermal tolerance of the tissues affected is low (56 °C and 72 °C for coagulation of body proteins and bone collagen respectively). This is the main factor that is responsible for bone necrosis associated with acrylic bone cement. To avoid this, sucrose crystals have been added to acrylic cement. The mixture has a lower polymerization temperature and greater porosity, allowing for better ingrowth of bone into the cement pores [ ]; however, the resultant lower mechanical resistance limits its use [ , ]. The same can be achieved by adding tricalcium phosphate, which lowers the reaction temperature. The non-polymerized monomer is cytotoxic [ ], which can cause histopathological changes in soft tissues and bones.