Digitized slice interposition in forensic dental radiographic identification. An in vitro study.

Traditional methods of comparison involving the presence of missing teeth, dental restorations, and other pathological features may be difficult due to the reduction in dental restorations in today's population. This study demonstrates an alternative method of identification using digitized images. It utilizes anatomical structures such as dental root morphology and spatial relations of teeth roots and their supporting structures on simulated antemortem and postmortem radiographs as the basis for identification. A total of 39 mandibular specimens were used and two radiographs representing the antemortem and postmortem radiographs of each hemimandible were exposed by two operators using different x-ray generators. The radiographs were scanned and digitized. The identities of the antemortem and postmortem radiographs were kept from the operator. Following this, horizontal sections were digitally cut from the antemortem radiographs through the roots approximately halfway between the neck of the tooth and the root apex. This section was manipulated onto the postmortem radiograph by using a computer graphics program and a quantitative comparison of the alignment of normal dental anatomical landmarks was undertaken. The technique enabled perfect matching of all 39 specimens by antemortem and postmortem dental radiographs. The mean number of identifying points was 17.5 and the mean number of nonmatching points was 0.1. The mean concordance was 99.2% between the antemortem and postmortem radiographs.