Biomaterials for reconstruction of the cranial vault

This review highlights some of the recent developments in biomaterials that are suited to reconstruction of the craniofacial skeleton. Although there is no ideal biomaterial, numerous alternatives are available to practicing surgeons that provide attractive alternatives to autogenous bone graft in the appropriate clinical settings. Biomaterials are particularly well suited for skeletal augmentation, since autogenous bone can often undergo unpredictable resorption in these applications. Although all of the biomaterials reviewed in this discussion seem to maintain their volume over time, porosity of the biomaterial may be a significant factor in determining bone ingrowth into the implant. Methyl methacrylate is nonporous, and no bone ingrowth is expected. Cement paste implants tend to contain micropores, and both experimental and clinical evidence indicates that there is less long-term bone in-growth into these biomaterials than in implants with macroporous architecture. Biomaterials presently reviewed that have a macroporous architecture and have demonstrated bone ingrowth in clinical and/or experimental studies include ceramic and granular forms of hydroxyapatite, hard tissue replacement polymer, porous polyethylene (Medpor), bioactive glasses (Nova Bone), and demineralized bone paste. Prefabricated biomaterials and those that set as a cement are not designed to change dimension over time, and are therefore best-suited for cranial vault reconstruction after completion of skull growth. Biomaterials discussed in the present review subject to these limitations include methyl methacrylate, ceramic, and cement paste forms of hydroxyapatite, Hard Tissue Replacement polymer, and porous polyethylene (Medpor). In theory, granular forms of hydroxyapatite, bioactive glasses (Nova Bone), and demineralized bone paste may remodel in the growing craniofacial skeleton, but to date there are no long-term clinical studies evaluating how these biomaterials adapt to the growing skull.