Disclosed herein is a composition suitable for use in spinal surgery. The composition generally includes a reaction product or settable mixture of first and second components, the first component including a spray-dried inorganic filler, a radical donor, and a pre-polymerized vinyl polymer, and the second component including a radical scavenger, a diluent, a polymerization accelerator, and a reactive monomer. Furthermore, disclosed herein is a method of making the composition, which generally includes mixing the first and second components under conditions suitable to form a curable reaction product.