The uniqueness of the human dentition as forensic evidence: a systematic review on the technological methodology

Abstract

The uniqueness of human dentition is routinely approached as identification evidence in forensic odontology. Specifically in bitemark and human identification cases, positive identifications are obtained under the hypothesis that two individuals do not have the same dental features. The present study compiles methodological information from articles on the uniqueness of human dentition to support investigations into the mentioned hypothesis. In April 2014, three electronic library databases (SciELO®, MEDLINE®/PubMed®, and LILACS®) were systematically searched. In parallel, reference lists of relevant studies were also screened. From the obtained articles (n = 1235), 13 full-text articles were considered eligible. They were examined according to the studied parameters: the sample size, the number of examined teeth, the registration technique for data collection, the methods for data analysis, and the study outcomes. Six combinations of studied data were detected: (1) dental shape, size, angulation, and position (n = 1); (2) dental shape, size, and angulation (n = 4); (3) dental shape and size (n = 5); (4) dental angulation and position (n = 2); (5) dental shape and angulation (n = 1); and (6) dental shape (n = 1). The sample size ranged between 10 and 1099 human dentitions. Ten articles examined the six anterior teeth, while three articles examined more teeth. Four articles exclusively addressed three-dimensional (3D) data registration, while six articles used two-dimensional (2D) imaging. In three articles, both imaging registrations were combined. Most articles (n = 9) explored the data using landmark placement. The other articles (n = 4) comprised digital comparison of superimposed dental contours. Although there were large methodological variations within the investigated articles, the uniqueness of human dentition remains unproved.

Absence of Statistical and Scientific Ethos: The Common Denominator in Deficient Forensic Practices

“…In addition to this sort of syllogistic argument from common sense that bitemark analysis should work as claimed, there were several papers in the literature purportedly supporting this premise, some of which are at least partially inferential in nature rather than empirical. The recent review paper by Franco et al (2014), conducted a highly detailed literature search looking for studies that examined the claim that the human dentition as recorded in a bitemark was unique, and found a total of 13 published papers that addressed the issue using datasets ranging in size from 11 to 1099 specimens (Disclosure: One of the coauthors of this article, H. D. Sheets, was a co-author on a number of these papers). Of the four papers that attempted to claim the biting dentition was unique, the sample sizes were 10, 397, 50, and 13.…”

Positive identification of a decomposed human body through forensic anthropology and smile photographs - a case report

“…The human identification process is strongly supported by unique forensic evidence found on teeth. Specifically, the human teeth contain valuable information detectable during post-mortem (PM) exams that can be tracked to ante-mortem (AM) records [1].…”

“…In a second and special scenario, the AM data may not be available, making necessary (1) multidisciplinary and (2) alternative forensic investigations [4]. (1) Multidisciplinary investigations are observed from a PM scope, in which the reconstruction of an anthropological profile becomes essential [2,5]. This procedure aims to collect cadaveric information related to age, stature, sex, and ancestry of the victim [5,6] to narrow searches from police lists of missing persons [2].…”

Unique or not unique? that is the question! – opinion article on a bitemark scope

“…In general, the identification procedure is performed on a comparative basis matching ante-mortem and post-mortem dental data 10 . Yet the second mainly concerns the identification of potential perpetrators (suspects) of bitemark injuries, in which uniqueness may be assessed based on the combination of morphological dental traits, such as shape; size;angulation and position, found within the suspect's dentition11 . In this scenario, the identification process is often performed matching the bitemark pattern with the suspect's dental impressions12 .…”