In the history of medicine, many surgeons have been tried to reconstruct lost tissue and correct deformity, attempts to use implant materials have probably paralleled those involving autogenous tissue. Recently there has been an acceleration in the understanding of the requirements and potentials of implant materials caused by collaboration between material scientists, biomaterials engineers, clinicians, and clinical investigators. Alloplastic materials have become an essential part of reconstructing the function and contour of the craniofacial skeleton. Bone is a specialized form of connective tissue, which provides support, and protects vital and delicate organs. Bone is embryologically derived from mesenchymal tissue through membranous and endochondral ossification. In the clinical field, the need for bone graft has been increased due to trauma, tumor, craniosynostosis, and pure esthetic bone surgery. Various types of bone grafts have been used to repair craniofacial bone defects over many years, but the autogenous graft has many disadvantages, such as, limited donor sites, donor morbidity, pain, growth deformity and resorption. Many surgeons working in a number of centers around the world have created substitutes and simpler methods for bone replacement. As the alloplatic bone substitute has been advanced, many synthetic substitutes are replaced by bone in vivo over time. The ideal material should be cost effective, non-toxic, non-antigenic, non-carcinogenic, and inert in the body fluids, be easily shaped at the operating table, and maintain its desired form and consistency in situ. This article reviews several of the more commonly used materials for craniofacial reconstruction and summarizes their mechanical properties and clinical aspects.