- Bite Mark Analysis
- Age Estimation
- Disaster Victim Identification
- Expert Identification for the Courts
Bite Mark Analysis
Assailants occasionally leave tooth marks on their victims’ bodies. Unlike a bruise or ‘black eye’, there may be characteristics in the mark which can identify the assailant. There may be characteristics which can exclude other suspects.
These marks change with time, and since especially in live victims, the first person to suspect a bite mark is never the odontologist, it is important to obtain a good undistorted photograph, with a scale clearly shown in the plane of the mark, as soon as possible.
Later, the odontologist can take impressions of a suspect’s teeth, and compare measured photographs of the casts with the photographs of the injury. An opinion can then be given as to whether the suspect is excluded or not.
Age estimation
The development of the teeth follows a fairly regular timetable, and by examining the dental development of an individual, a fairly accurate estimation of age can be given, up to about twenty-one years.
This has become useful in determining the rights of young asylum seekers, who arrive with no documentation, but the knowledge that the younger they appear to be, the ‘better’ their entitlement appears to be. Further controversy has entered the situation, in that an x-ray has to be taken for this to be at all accurate, and issues of consent, and clinical need have muddied the waters somewhat.
After the age of twenty-one, it becomes much more difficult to assess the age from the dentition, because it becomes a matter of assessing the wear on the tooth surfaces, and for this, an idea of the culture in which the person lived is necessary.
Disaster Victim Identification
If a motorcycle crashes into a tree, and explodes, leaving two bodies with no paperwork, the police will discover that the owner and her girlfriend are missing. The dental records of the two will be sought, and the two bodies identified. If the records are inadequate, they only need to distinguish between the two bodies to establish which is which.
If a commercial airliner crashes into a hotel, the situation is a little more complicated. The aeroplane is technically ‘closed’, so the people aboard are known, but it cannot be certain who was in the hotel at the time. In this situation, a higher level of proof of identity will be required, and visual identification may not be acceptable on its own.
The process of dental identification is much the same as in individual cases, except that dental evidence is also used to exclude possible ‘matches’ reducing the odds for other agencies.
Dental evidence played a significant part in the identification of victims from the 7⁄7 London Bombings, the South East Asian Tsunami, the Concorde crash in Paris, the Mont Blanc Tunnel fire, the Zeebrugge Ferry disaster, and many other disasters.
Expert Identification for the Courts
Identification of the dead is not usually a problem. People are usually identified by relatives, or documents such as passports, or identity devices such as military ‘dog tags’, or hospital ID bracelets.
If the death triggers an inquest, one of the Coroner’s duties is to determine identity beyond reasonable doubt.
If the face has become too disfigured to compare with photographs, or to show to relatives, reasonable doubt as to the identity may exist, and the value of identity documents may be questioned.
Contrary to the impression given by the media, the next step is not ‘facial reconstruction’, or ‘DNA’, but to get a Forensic Odontologist’s opinion. If dental records are available for the ‘missing person’, they can be compared with the dental features of the unidentified body, and the Odontologist’s opinion given as to whether the identity is confirmed ‘beyond reasonable doubt’, or not.
If the dental evidence is flawed - most usually by inadequate dental records of the missing person, other forms of establishing identity may be ‘added’ to reduce doubt. Digital photographs of the missing person smiling may be overlaid onto images of the teeth of the body, and if there are suitable characteristics that coincide, this evidence can be added to other evidence to establish identity.
Evidence offered by the Forensic Pathologist can add weight to an identification - scars, piercings, tattoos, the presence or absence of organs (like the appendix, which may have been surgically removed in life), or of implanted surgical devices. These features may not be unique - except that surgical devices (even dentures) often have a serial number, which can be conclusive.
Clothing and possessions are also used to add weight to the evidence, if it can be proved that the missing person was wearing a particularly unique item at the time of death.
DNA processing at present takes a little more time than it appears to on the television, is not always conclusive, and is more expensive. This situation will certainly improve in the future.