Three Dimensional Superimposition of Dentition Isosurfaces for Personal Identification in Forensic Odontology

Abstract

It is well documented that many Australians have few or no dental restorations. Unfortunately it is not uncommon to see such individuals in the mortuary where, often because of disfigurement caused by trauma, they undergo identification by Forensic Odontology.

Forensic Odontologists are less enthusiastic to declare that a person has been identified beyond doubt on the basis of comparing anatomy of teeth and bones than they are when comparing the distinctive morphology of radiopaque dental restorations visible in dental radiographs.

A method of increasing the degree of confidence in the match is available when ante-mortem dental study casts or cone-beam CT scans of the dentition of a suspected deceased are available. In such cases, a CT scan or a three-dimensional laser scan of the dentition of the deceased can be obtained, and isosurfaces can be created from each of the two sources (postmortem and antemortem). These can then be superimposed in three dimensions and the degree to which the surfaces match can be expressed by the use of colour to indicate increasing levels of match or mismatch.

The process will be illustrated and its strengths and limitations discussed.