Source: HighWire, Stanford University
By: A Buddula, DA Assad, TJ Salinas, YI Garces, JE Vloz and AL Weaver

Purpose: To study the long-term survival of dental implants placed in irradiated bone in subjects who received radiation for head and neck cancer. Materials and Method: A retrospective chart review was conducted for all patients who received dental implants following radiation treatment for head and neck cancer between May 1, 1987 through July 1, 2008. Only patients irradiated with a radiation dose of 50?Gy or greater and those who received dental implants in the irradiated field after head and neck radiation were included in the study. The associations between implant survival and patient/implant characteristics were estimated by fitting univariate marginal Cox proportional hazards models. Results: A total of 48 patients who had prior head and neck radiation had 271 dental implants placed during May 1987 to July 2008. The estimated survival at 1, 5, and 10 years was 98.9%, 89.9%, and 72.3%, respectively. Implants placed in the maxilla were more likely to fail than implants placed in the mandible.There was also a tendency for implants placed in the posterior region to fail compared with those placed in the anterior region. Conclusion: Dental implants placed in irradiated bone have a greater risk for failure. Survival is significantly influenced by the location of the implant (maxilla or mandible, anterior or posterior).