Forensic Radiographic Identification Using Manipulated Digital Dental Images

Abstract

A technique was developed for the assessment of forensic identification using dental radiographs. The technique involved the digitisation of dental radiographs, cutting of a horizontal section from an antemortem radiograph and superimposing it over the same geographic location on the postmortem radiograph. The technique was useful in vitro and in an in vitro mock mass disaster. It was accurate within both the paediatric and permanent dentition and not useful in subjects with changing dentitions (mixed dentition). Image density (with and without optical enhancement) did not prove to be an impediment to the technique although extremes of image contrast did. Within the range of dental xray generators settings, contrast could be altered in a manner to allow matching. Differences in the vertical angulation of the x-ray beam did not influence the technique although horizontal angulation was a critical factor. Alterations in focal-film distance did not adversely affect the use of this technique. The three different scanning systems used were .all adequate for the purpose of the technique and the images could be compressed and transferred with little difficulty. Analysis of a group of actual Coroner's cases proved the technique to be useful in a timely fashion, for actual field identifications with minimal inter and intra operator error.