[Bone substitutes]

Bone substitutes, used to fill a defect after a surgery or a trauma, provide a mechanical support and might induce bone healing. They constitute an alternative to autogenous bone grafts, the 'gold standard' which remains the reference despite its risk of postoperative complications. The clinician choice of a bone substitute is based on the required bone volume, the handling (injectability, malleability) and mechanical properties (setting time, viscosity, resorbability among others) of the material. Bone substitutes are commonly used in orthopedic surgery, neurosurgery, stomatology and dental applications. Their use increases steadily, with the recent clinical development of injectable forms. In addition, novel technologies by subtractive or additive techniques allow today the production of controlled architecture materials. Here, we present a bone substitutes classification according to their origin (natural or synthetic) and chemical composition, and the most common use of these substitutes.