Teeth and Identification

Forensic Odontology

Teeth are the hardest structure in the body. As a result, even when preservation conditions are very poor and the rest of the skeleton decays, the teeth are often still preserved. Teeth can also withstand quite high temperatures. The robust nature of the teeth means that they are often a vital source of information about a deceased person. This is particularly important in disaster situations (both natural and human-made) and in circumstances where the body is recovered a long time after death.

Role of teeth in personal identification

There are two key ways the dentition can contribute to the identification of a deceased person in forensic contexts:

1. A post-mortem dental profile can contribute information such as age, ancestry, socio-economic status, occupation, habits, systemic diseases, dental disease history etc. This may not lead to a positive identification but may narrow the pool toward a presumptive identity.

2. A comparison of ante-mortem and post-mortem dental characteristics (size, shape, arrangement and alignment) and restorative status can provide a positive identification. This requires accurate and comprehensive dental records (written and radiographic evidence, but also may include clinical photographs or dental models) to be available for the presumptive deceased.

Although not scientifically proven, researchers are confident that teeth are individual (we don’t say unique). Restorative dental treatment adds to the individuality of the dentition as fillings are often created manually or by ‘hand’, so no two restorations will have completely the same outline. A wide variety of available restorative materials also adds to the individuality of the matrix. With good ante-mortem dental information, it can be possible to complete a dental identification on an individual with no restorations.

When completing a comparative dental identification, it is important to assess the post-mortem status of each tooth against the information recorded in the ante-mortem dental record. If differences are observed they may be explainable (e.g. due to time elapsed between ante-mortem record and post-mortem examination, errors in charting -wrong tooth recorded), or they may be unexplainable (e.g. a tooth present in the mouth that was recorded as being extracted). Unexplainable differences may exclude the identification.

Some important things to keep in mind when using teeth for forensic identification are:

• Partial removable prosthetic appliances (partial dentures) can contribute to the dental data set, but full removable prostheses (full dentures) need to be labelled with patient details (i.e. individualised) to contribute to the identification.
• Similarities are important for positive identification, but differences are critical for excluding the identification.
• Teeth can also be a source of DNA for a genetic profile to assist with identification