Forensics: Solving Mysteries
The need to identify victims and help with solving crimes requires specialized training in forensic science and death investigation. Dentistry plays an important part in this process. Dentists who practice forensic science are called forensic odontologists. The odontologist creates dental profiles from existing dental records and creates postmortem dental profiles from a dental autopsy examination and dental radiographs (X-Rays). The odontologist compares these two types of dental profiles and makes a conclusion about the victim's identity.
- A person can be identified from the amount of DNA in saliva left behind on a postage stamp.
- Teeth survive most postmortem circumstances: decomposition, immersion in water, burial and fires reaching 1100°C.
- Unlike fingerprint analysis there is no minimum number of matching points or features required for a positive identification in forensic odontology.
- Even a tooth with root canal treatment can provide enough genetic material to perform DNA analysis.
- The Roman Empress Agrippina identified her husband Claudius' former wife Lollia Paulina from her crooked teeth.
- Paul Revere identified the body of Dr. Warren from a partial denture Revere had made for Warren in, possibly, the first dental forensic identification in the United States.
- In 1850, Dr. Webster was convicted of murdering Dr. Parkman after a denture found in Webster's laboratory was linked to Parkman.
DNA testing is done when a victim cannot be identified by comparing dental records. In DNA comparison cases the teeth can still provide the necessary material to make a positive identification because:
- Teeth are an excellent source of DNA.
- Teeth that have been exposed to many different environmental conditions still contain sufficient DNA for analysis.
DNA comparison is not used first because:
- It is still very expensive.
- The DNA analysis is performed in a laboratory and not at the disaster site.
- There are too few laboratories doing DNA comparisons.
- DNA comparison takes a longer time to do than comparing dental records.
- Reference samples of before death (antemortem) DNA are still needed for comparison.
- From a toothbrush, hair brush or medical records.
The Forensic Odontologist also helps solve cases by examining bitemark evidence and deciding if there is sufficient similarity with the suspect's teeth and the bitemark to include this person as a suspect in the case. The most valuable bitemarks record features from specific teeth with distinct traits. When these traits are recorded it may be possible to compare them to the specific teeth, which may help identify the person that caused the injury. The overall forensic value of the bitemark is reduced if the teeth have few or no individual characteristics or if these characteristics are not recorded well in the injury. Saliva containing DNA will be deposited on the skin during biting and may provide sufficient DNA to obtain a DNA profile of the suspect.
