Differentiation of dental restorative materials combining energy-dispersive X-ray fluorescence spectroscopy and post-mortem CT

Abstract

Today, post-mortem computed tomography (CT) is routinely used for forensic identification. Mobile energy-dispersive X-ray fluorescence (EDXRF) spectroscopy of a dentition is a method of identification that has the potential to be easier and cheaper than CT, although it cannot be used with every dentition. In challenging cases, combining both techniques could facilitate the process of identification and prove to be advantageous over chemical analyses. Nine dental restorative material brands were analyzed using EDXRF spectroscopy. Their differentiability was assessed by comparing each material's x-ray fluorescence spectrum and then comparing the spectra to previous research investigating differentiability in CT. To verify EDXRF's precision and accuracy, select dental specimens underwent comparative electron beam excited x-ray spectroscopy (EDS) scans, while the impact of the restorative surface area was studied by scanning a row of dental specimens with varying restorative surface areas (n = 10). EDXRF was able to differentiate all 36 possible pairs of dental filling materials; however, dual-energy CT was only able to differentiate 33 out of 36. The EDS scans showed correlating x-ray fluorescence peaks on the x-ray spectra compared to our EDXRF. In addition, the surface area showed no influence on the differentiability of the dental filling materials. EDXRF has the potential to facilitate corpse identification by differentiating and comparing restorative materials, providing more information compared to post-mortem CT alone. Despite not being able to explicitly identify a brand without a control sample or database, its fast and mobile use could accelerate daily routines or mass victim identification processes. To achieve this goal, further development of EDXRF scanners for this application and further studies evaluating the method within a specific routine need to be performed.

Keywords: Corpse identification; Dental identification; Dental restorative materials; Energy-dispersive x-ray fluorescence; Forensic identification; Virtopsy.