Effects of radiation therapy on craniofacial and dental implants: a review of the literature

ObjectivesThe theories of the effects of radiation therapy on craniofacial and dental implants have been challenged by new models. Animal and clinical studies differ on the importance of dose effect and implant location regarding implant survival. Our purpose was to explore the risks of irradiation regarding dose levels, timing of radiation, implant location, and material.Study designA systematic search of the literature was performed to identify studies reporting animal and human data on the success of implants in irradiated versus nonirradiated bone.ResultsEleven animal studies exploring histomorphometric, biomechanical, and histologic features of implants in irradiated bone were summarized. Sixteen human clinical studies evaluating craniofacial (n = 8) and dental (n = 8) implants in irradiated bone were summarized. No meta-analyses of dental implants in irradiated bone were found. Efficacy studies comparing different implant types in irradiated bone were not found.ConclusionStudies from both animal subjects and human patients indicate that irradiated bone has a greater risk of implant failure than nonirradiated bone. This increase in risk may be up to 12 times greater; however, studies making these comparisons are of poor to moderate quality, so the magnitude of this difference should be accepted with caution.