Dose inhomogeneities on surfaces of different dental implants during irradiation with high-energy photons

The aim of this study was to determine the radiation doses in mucosa and bone close to the surface of different dental implant materials. Radiation dose was measured at the interface of bone or soft tissue and various implant materials for 6 MV photons generated by a medical linear accelerator using a phantom and ultrathin thermoluminescent dosemeters. Increasing thickness of implant materials resulted in a dose decrease in bone immediately behind the implants. Directly in front of titanium implants, dose increases of 18.2% and 30.4% were found in bone and soft tissue, respectively, independent of implant thickness and surface structure (polished/plasma coated). Even a titanium coating with 70 microm hydroxyapatite did not affect the scattering dose. In contrast, for aluminium oxide ceramics, a scatter-induced notable dose increase could not be assessed. During irradiation with high-energy photons, an implant-induced dose enhancement could be reduced in bone using the technique of multiple fields and in soft tissue using ceramic abutments.