"Identified", "probable", "possible" or "exclude": The influence of task-irrelevant information on forensic odontology identification opinion.

In a mass disaster situation, identification of the deceased utilising comparison of dental features is frequently heavily relied upon to facilitate rapid and accurate outcomes. The method consists of the comparison of clinical and radiographic records depicting oral structures and dentition to allow an opinion to be produced on a presumed identity. Current forensic odontology identification opinions are expressed as categories of levels of identification. Categories such as "Identified", "Probable", "Possible" and "Exclude" are used in various forensic odontology identification scales. The boundaries between the levels of the scales are not fixed; hence, category selection is highly subjective. It is uncertain how extrinsic factors such as exposure to contextual task-irrelevant information or operator experience influence category selection. In this study, forensic odontologist and dentist participants read task-irrelevant context case information containing either strong or weak identification or non-identification suggestions before evaluating and comparing pairs of true matching and non-matching dental radiographs. They were then asked to form an opinion regarding identification using one of four categories from the INTERPOL scale. Context information was found to influence categorical decisions. The magnitude and direction of influence depended on the type of participant, the true match status of the radiographs, and the strength and direction of bias of the context. The results of this study demonstrate the contextual effect and fluidity of the boundaries between the categories on the identification scale and highlight the need for stringent protocols to be developed regarding the use of these categorical scales to enable decision making to be more objective.

The biasing impact of irrelevant contextual information on forensic odontology radiograph matching decisions.

The potential biasing effect of irrelevant context information on the forensic odontology method of radiograph-based identification has never been empirically investigated despite being a recognized problem in other forensic science disciplines. This study examines the effect of irrelevant context information on the probability judgment of match (JOM) of practicing forensic odontologist and dentist participants who were asked to match pairs of dental radiographs supplemented with irrelevant case information. The irrelevant case information contained domain task-irrelevant context information which varied in strength (strong or weak). It suggested either supportive or contradictory bias relative to the actual match status of the radiograph pairs. The dental radiographs consisted of verified match and non-match radiographs pairs sampled and de-identified from actual forensic cases. Changes in accuracy and JOM between supportive and contradictory contexts conditions revealed a contextual bias. Mixed model analysis showed that strong supportive context increased the odds ratio of correct decisions by a factor of 2.4 [1.23, 4.46]; p = 0.0097. Consistent with the biasing effect, the JOM score differences between strong supportive and contradictory irrelevant context information were 1.03 and 0.43 respectively for the non-match and match decisions. The direction of context suggestion (p = 0.0067), the radiograph match status (p = 0.014), and their interactions (p = 0.0061), were all found to impact the participants' decision. The weak context information was not strong enough to have a significant effect on accuracy or JOM scores. This study demonstrates that radiograph match judgment is affected and can be biased by strong irrelevant contextual information.

Interpretation, confidence and application of the standardised terms: Identified, Probable, Possible, Exclude and Insufficient in forensic odontology identification.

Forensic odontology identification scales are used to express certainty of identifications of deceased persons. These standardized scales are assumed to convey unambiguous expert opinions and facilitate communication between forensic odontologists and end users. However, to date no studies have investigated how the experts interpret and use these scales. Forensic odontology identification scales are used to express certainty of identifications of deceased persons. These standardized scales are assumed to convey unambiguous expert opinions and facilitate communication between forensic odontologists and end users. However, to date no studies have investigated how the experts interpret and use these scales. This paper aims to examine the interpretation of the DVISYS forensic identification scale and choices of the levels in the scale subsequent to, and derived from, comparison of pairs of dental radiographs by extending the analysis of the data collected in the study by Page and Lain et. al. 2017. The studied variables: self-reported confidence, forced binary decision of match and non-match, choice of level in the DVISYS scale (Identified, Probable, Possible, Insufficient and Exclude) were further analysed in this study using mixed models for relationships between the choices of level in the identification scale and the fundamental beliefs of likelihood of identification. The results of this further analysis showed that the reported confidence of the decisions was correlated to the difficulty of cases, and as confidence decreased the use of less definitive terms ('Probable', 'Possible' and 'Insufficient') increased. 'Probable' and 'Possible' were used mainly in underlying beliefs below that of 'Identified' whereas 'Insufficient' was used mainly to convey a sublevel of 'Exclude'. The use of 'Insufficient' in this study was not consistent with the prescribed definition of the term. The participants of the original study were not aware of the difficulty grading of the cases nor were required to grade them, however the reported confidence was systematically correlated to difficulty. Furthermore, indicated confidence level was correlated with choice of level on the scale in general, but the interpretation of the definition and application of the terms varied. The findings reported here contribute to the foundational knowledge of factors governing the interpretation and application of the DVISYS forensic odontology identification scale and suggest that this scale may need to be modified.

A note on digital dental radiography in forensic odontology.

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.