The applicability of using different energy levels in CT imaging for differentiation or identification of dental restorative materials

Purpose: The goal of this study was to investigate whether different computed tomography (CT) energy levels could supply additional information for the differentiation of dental materials for forensic investigations. Methods: Nine different commonly used restorative dental materials were investigated in this study. A total of 75 human third molars were filled with the restorative dental materials and then scanned using the forensic reference phantom in singlesource mode. The mean Hounsfield unit values and standard deviations (SDs) of each material were calculated at 120, 80 and 140kVp. Results: Most of the dental materials could be differentiated at 120kVp. We found that greater X-ray density of a material resulted in higher SDs and that the material volume could influence the measurements. Conclusion: Differentiation of dental materials in CT was possible in many cases using single-energy CT scans at 120kVp. Because of the number of dental restorative materials available and scanner and scan parameter dependence, as well as the CT imaging artifacts, the identification (in contrast to differentiation) was problematic