We have synthesized a filler-reinforced silorane composite that has potential applications in orthopaedic surgery, such as for a bone stabilizer. The purpose of the present work was to develop a method for estimating four properties of this material; namely, maximum exotherm temperature, flexural strength, flexural modulus, and fracture toughness. The method involved the use of mixture design-of-experiments and regression analysis of results obtained using 23 formulations of the composite. We validated the estimation method by showing that, for each of four composite formulations that were not included in the method development, the value of each of the aforementioned properties was not significantly different from that obtained experimentally. Our estimation method has the potential for use in the development of a wide range of orthopaedic materials.