Summary Endosseous implants play a paramount role in the successful functional rehabilitation of patients who have undergone resection of tumors from the maxillofacial region. Vascularized and nonvascularized bone-grafting techniques allow predictable restoration of form; however, failure to meet the requirements of conventional removable prostheses often is encountered because of mucosal alterations, loss of vestibular anatomy, and neurosensory loss. This is further complicated by radiation therapy, which produces mucosal alterations, xerostomia, and potentially osteoradionecrosis. Full-coverage removable prostheses generally are nonretentive, and patients often find themselves removing their prostheses in order to eat. Radiation therapy decreases bone-healing capacity and produces soft-tissue injury. Experiments have shown that overall osseo-integration rates for endosseous implants are less in irradiated bone than in normal bone but improve if the interval between radiation therapy and implant placement increases and if longer osseo-integration times are allowed prior to implant loading. Animal studies have shown that bone-healing capacity is significantly improved 1 year after radiation therapy. Therefore, a delay between radiation therapy and implant placement is suggested. Timing of implant placement in humans remains controversial. The results of animal studies regarding the effects of radiation on rates of implant integration are similar to clinical experiences. Although immediate implant placement in conjunction with bone grafting has been performed, the advantages of delayed placement far outweigh the benefits of immediate placement. The advantages of delayed placement of implants after primary reconstruction include the ability to: Identify those patients who are motivated and disease-free; Allow the effects of radiation on soft tissue and bone to subside; Eliminate the risk of devascularization of vascularized grafts that can occur with immediate placement; Eliminate the risk of delivering higher doses of radiation to adjacent tissues if implants are in the radiation field; Perform secondary soft-tissue procedures, often needed to provide an adequate peri-implant environment, in conjunction with implant placement; and Allow time for bone remodeling and healing, thereby reducing the risk of early implant failures. HBO therapy increases soft-tissue and bone healing through the processes of neoangiogenesis and fibroplasia, which produce higher oxygen tension in radiated tissues. Experiments have shown that HBO therapy increases rates of osseo-integration of implants in irradiated bone. Although the relationship between the use of HBO therapy and rates of osseo-integration in radiated bones of humans has not been established, higher rates of osseo-integration are expected if HBO therapy is utilized. Recent clinical studies report the successful use of implants and implant-retained prostheses in the restoration of form and function in patients who have undergone maxillofacial tumor ablation. The effects of radiation therapy and HBO therapy on rates of implant integration have been demonstrated but not scientifically established. Larger sample sizes and consistency in reporting the type and dosage of radiation and whether HBO therapy is used are needed. Data standards for future studies are required in order to establish treatment modalities regarding the use of implants for the purposes of esthetic and functional rehabilitation of patients with maxillofacial tumors.
