Ear identification: A multi-ethnic study sample.

The external human ear is considered to be highly variable among individuals. Hence, forensic applications could be explored for human identification. This research compares the usefulness of Cameriere's ear identification method, in samples originating from six different countries (Brazil, India, Japan, Russia, South Africa and Turkey) in order to examine possible differences in their accuracy values. A sample of 2,225 photographs of the external human ear (1,134 left and 1,091 right ears) from 1,411 individuals (633 females and 778 males) was collected. The samples included healthy subjects with no systemic disorders and without any craniofacial trauma, maxillofacial abnormalities, auricular anomalies, ear diseases or previous auricular surgery. Cameriere's ear identification method was applied and measurements were performed on the images of each ear, considering four anatomic regions: helix, antihelix, concha, and lobe. The quantified measurement values were converted into a proposed coded number system. A search for identical codes was accomplished to find out the distinctiveness of the morphology of the human ear. The combined codes of left and right ears of each of the 814 subjects were not repeated in this multi-ethnic study sample. Dirichlet's distribution and the inherent study equation showed that the probability of two different individuals having the same code (false-positive identification) was found to be <0.0007. Because of the distinctive metrics of the ratios of external human ears, studies with Cameriere's ear identification method may be valuable for human identification. Studying the differences between the left and right ears of the same individual and across different ethnic groups could contribute to the development of supplementary tools for human identification.

Use of non-clinical smile images for human identification: a systematic review.

Human identification using Forensic Dentistry occurs through comparative analysis of ante-mortem (AM) and post-mortem (PM) data. With the constant improvement of technology, photographs became a common source of AM data. When clinical dental records are not available, images showing the smile can be useful in human identification. The aim of this study was to investigate human identification techniques through the analysis of smile images in the available literature. Studies on human identification through the analysis of smile images were searched in the scientific literature. The search resulted in 4,043 studies. After screening, 14 studies were considered eligible. Eleven were case reports, two were pilot studies and one a technical note. From the eligible studies, in addition to the methodological data, information about the sample, used techniques and results regarding human identification were extracted. Three techniques were detected: direct comparison of morphological characteristics, AM/PM image overlap, and the analysis of smile lines. One or more associated techniques were used for human identification. Authors highlighted as a common limitation of the techniques the quality of the available images, the difficulty in reproducing PM the same images AM, and the eventual image modifications performed by the victim before posting in social media. Advantages included the low-cost aspect of the technique, as well as a potential fast and accurate procedure (depending on the quantity and quality of evidence). In general, studies considered the technique useful and adjuvant for human identification.