Dental identification by comparison of antemortem and postmortem dental radiographs: influence of operator qualifications and cognitive bias

Dental forensic identifications based on comparison of antemortem and postmortem radiographs provide effective and reliable evidence. There are no standardized procedures for assessing similarities between different types of dental radiographs (e.g. orthopantomograms, bitewings, and periapical radiographs), and the operator's subjective judgment can considerably affect identification. The purpose of this study is to evaluate the potential influence of experts' qualifications, training, and cognitive bias on the accuracy of identification. Seventy-eight differently qualified and experienced experts underwent an identification test. The expert sample was composed of 10 specialists in emergency care (ER), 10 specialists in legal medicine (ML), 20 pregraduate dental students (STU), 12 dentists (DENT), 20 dentists educated in forensic odontology (DENT-TRA), and 6 experienced forensic odontologists (FOR). The simulated cases required participants to assess the possible matching of 42 postmortem intraoral radiographs with 16 antemortem panoramic radiographs. Accuracy and specificity for the different operator groups were as follows: ER, 0.76-0.70; ML, 0.76-0.88; STU, 0.89-0.82; DENT, 0.87-0.97; DENT-TRA, 0.88-0.92; and FOR, 0.97-1. As evidenced by high rates of accuracy and repeatability, the most experienced forensic odontologist consistently outperformed operators less or differently educated and trained, especially for difficult cases. In our sample, the dentists who received additional education in forensic odontology did not necessarily perform better than dentists who had not received this additional education. Some cognitive bias, mainly the so-called observer effect, emerged as a possible source of outcome variability among the operator groups.