Likelihood Ratio Approach to Identification in Forensic Odontology

• NCJ Number: 226735
• Journal: Problems of Forensic Sciences Volume: 76 Dated: 2008 Pages: 339-353
• Author(s): Jean-Luc Gremaud
• Date Published: 2008
• Length: 15 pages
• Publication Format: Article
• Publication Type: Report (Technical); Report (Study/Research)
• Language: English
• Country: Poland

Annotation

This study applied a likelihood ratio (LR) to a comparison of postmortem (PM) dental data of an unknown deceased person to antemortem (AM) data of a presumptive person, which allowed for an assessment of the value of the compared dental data for the purpose of identifying the deceased person.

Abstract

The forensic odontologist must decide whether or not the identity of the deceased person corresponds to a presumptive identity based on a comparison of the PM dental characteristics of the deceased and the AM dental records of a presumptive person who is missing and may or may not be the deceased under investigation. The principle of a Bayesian framework consists of determining, with measured uncertainty, the degree of confidence that can be accorded to a specific hypothesis based on analytical results. This is expressed in the form of a likelihood ratio (LR). The LR indicates the likelihood that the attribution of the identity of the deceased to the presumptive person is true, based on the PM and AM dental features. This paper examines the issues of dental “intravariability” and “intervariability” in the LR’s calculation. “Intravariability” pertains to changes in a given person’s dentition over time, which may be of natural or accidental origin. Natural origin pertains to the natural development of teeth, starting with the successive eruption of primary teeth and their gradual loss, followed by the eruption of permanent teeth. Accidental intravariability involves intrusions such as cavities and other types of damage to teeth that require treatment; this changes the dentition profile. It is rare if not impossible to find up-to-date dental records of accidental intravariability. “Intervariability”pertains to the likelihood of similarities and variabilities in a comparison of the dentition of two people. This paper discusses how the proposed LR takes into account these factors. 3 tables, 1 figure, and 37 references