A note on digital dental radiography in forensic odontology

Abstract

Digital dental radiography, intraoral and extraoral, is becoming more popular in dental practice. It offers convenience, such as lower exposure to radiation, ease of storing of images, and elimination of chemical processing. However, it also has disadvantages and drawbacks. One of these is the potential for confusion of the orientation of the image. This paper outlines one example of this, namely, the lateral inversion of the image. This source of confusion is partly inherent in the older model of phosphor storage plates (PSPs), as they allow both sides to be exposed without clue to the fact that the image is acquired on the wrong side. The native software allows digital manipulation of the X-ray image, permitting both rotation and inversion. Attempts to orientate the X-ray according to the indicator incorporated on the plate can then sometimes lead to inadvertent lateral inversion of the image. This article discusses the implications of such mistakes in dental digital radiography to forensic odontology and general dental practice.

Keywords: Forensic odontology; dental; digital radiography; identification.

Figure 1

Laterally inverted OPG. The “L” indicated by the arrow means left. OPG = Orthopantomographs

Figure 2

Periapical radiograph of the same patient showing tooth 38. Note “a” in the corner, when the PSP is used with the correct side facing the X-ray source, and if placed with the indicator to the distal, a lower left radiograph should have the “a” positioned such as in this model of phosphor plate intraoral radiograph receptor. PSP = Phosphor storage plate

Figure 3

The above is a set of bitewings taken with the correct side facing the tube and the indicator in the correct orientation. In the right bitewing, the indicator is on the top distal corner while in the left bitewing, the indicator is the left distal corner. (Note: the common operator error – cone cutting)

Figure 4

This is the same right bitewing taken with reversed placement. The exposure is done with the correct side of the receptor not facing the X-ray source. Note the only clue is the indicator appearing on the lower right distal corner of the image; the contrast and clarity of the image is not affected

Figure 5

This is the same radiograph as the one in Figure 4. It was laterally rotated to correct the alignment of the indicator, resulting in an inversion of what was a right bitewing into a left bitewing