Digital Imaging Methods as an Aid in Dental Identification of Human Remains

Abstract

The physical comparison of known (K) and questioned (Q) evidence samples is an accepted tool in numerous forensic identification disciplines (1). A subset of this process is the use of antemortem and postmortem dental radiographs to identify unidentified human remains. This method has been generally accepted for decades (2). The outcome is performed with a considerable degree of accuracy, due in part to a finite pool of possible candidates for identification derived via the NCIC database, passenger lists, and law enforcement Missing Persons reports. This paper describes a dental identification comparison protocol that incorporated digital imaging technology in this process. The computer was used to create digital exemplars of the K and Q evidence that were spatially and quantitatively compared (3). The digital mode allowed direct metric and morphologic comparison through the aid of a digital camera, desktop computer, monitor, and printer. The well-known computer program Adobe® Photoshop ® 5.0 (4) was used to process the digital information in two forensic cases described in this paper. It is a commercially available digital imaging editing program that is operated on laptop and desktop computers possessing sufficient chip speed and RAM (Pentium II or equivalent and at least 76MB RAM) to open the large-size files generated by high-resolution digital capture devices. This program accepts raster-based image formats (e.g. .JPG, .BMP). Photoshop® is noted for its diverse imaging functions, which allow the computer monitor to be used as a comparison microscope when Q and K sample images are tiled side-by-side and/or superimposed. Two and three-dimensional Q and K evidence samples can be individually digitized and then independently resized to allow two-dimensional comparison. The investigator also has the ability to create magnified images (200% to 300%) when the original digital image has been captured at near photoquality resolution (300 dpi). The visual comparison of physical features on the computer monitor permits a large field of view and robust digital control over image quality. Photographic measurement and enhancement features of Adobe® Photoshop® mimics and in some circumstances surpasses the historic use of conventional photographic manipulation in forensic casework. This paper presents two cases processed via routine forensic odontology identification protocols. These protocols had minimal results due to limitations described in the case histories. The additional application of digital methods proved useful in the ultimate identification of these human remains.

Importance of radiography in forensic odontology- A brief review

“…Post mortem periapical radiographs were compared to ante-mortem lateral and postero-anterior radiographs of a missing person [6]. Another recently published report has highlighted the importance of dental digital imaging technology to compare ante-mortem and post mortem evidences [7]. The advantage of this modality is that it allows large field of view and excellent digital image quality when compared to conventional radiographs [7].…”

Potential contribution of periapical radiographic film image processing for forensic identification

“…Digital processing of radiographs allows adjustments of image quality from conventional films by mitigating the technical, processing and storage errors effect, also allowing greater definition of details 10 . Tools and controls to adjust temperature, saturation, brightness, contrast, sharpness, highlights, shadows and matrix can be an important resource for indicating x-rays in forensic identification.…”

Proposal for internet-based Digital Dental Chart for personal dental identification in forensics

“…Dental evidence plays an integral and well-known role in the identification of bodies, and there are innumerable examples of its usefulness, such as when public searches have been requested by the Ministry of Foreign Affairs of a particular country [1][2][3][4][5] .…”