|
|
| Dental
Matching |
| The uniqueness of a set of teeth is
a powerful tool in confirming the identity of someone unknown, especially
when a lack of DNA evidence is the case. You may be intrigued by the
number of clues an examination of teeth can provide. |
|
Choose one of the topics below to learn more:
--> The
uses of dental matching
--> Comparing
records
--> Alternative
factors
--> Bite
marks
|
| |
| The
Uses Of Dental Matching |
|
| Forensic
odontologists or in other words, forensic dentists, have
the job of examining dental evidence that is left behind after
a crime has been committed. Teeth are an excellent source of
identification, as they hard wearing and durable. With the ability
to survive fires that destroy evidence, burn human bones to
ashes and melt copper and glass, teeth are able to withstand
criminal's attempts to hide the crimes they've committed and
the evidence held within the crime scene and dental analysis
provides a cost efficient alternative to solving a crime. |
|
| *Worn
fillings and chipped teeth are valuable clues. Photo courtesy
of Valeri
Craigle and the Spencer
S. Eccles Health Sciences Library.
|
|
| |
| Comparing
Records |
|
|
At the scene of the crime, odontologists collect the skull or remaining
teeth, which are taken back to the forensic laboratory for the postmortem
dental investigation. X-rays are taken and if the jaw is completely
intact and the dental records used to compare are recent, the job
of proving a match is a relatively simple one. Dentists mark on
a chart the position of missing teeth, crowns, bridges,
fillings, caps, root canals and various other
treatments during a patient's routine check-up. The task of identifying
a victim is made more difficult when the dentist records and x-rays
are out of date or when the skull is severely damaged and has parts
missing.
|
 |
*To
the left is a comparison of two dental impressions, showing the
differences in dental structure between the teeth of a 30 year old
and a 5 year old. The size of the milk teeth compared to that of
the adult teeth, and the presence of a wisdom tooth in the adult
set, are evident differences.
Photo
is courtesy of Valeri
Craigle and the
Spencer
S. Eccles Health Sciences Library.
|
| |
| Alternative
Factors |
|
 |
Where
no dental x-rays are found, full-face x-rays are sometimes used
as an alternative record, as the sinuses present above the nose
have a unique shape in every person and can be used in the accurate
identification of a victim. If no dental, face or x-ray records
are present, the ability to make decisions about the victim's
identity is very restricted, but other guidelines are useful.
Some of these guidelines include the tooth roots becoming more
transparent in older people and the stage of development of
a child's teeth can determine their age. The teeth's pattern
of wear in adult's show the person's age, diet and the materials/dentistry
techniques used during dental treatment, which can point out
the country in which treatment was received. |
 |
| *
Two different sets of x-rays can be distinctly different and
used to prove/disprove a certain identity. Images courtesy of
www.imageafter.com. |
|
| |
| Bite
Marks |
|
|
Odontologists also play a vital role in the study of
bite marks. Human and animal teeth both leave conspicuous
marks. In the flesh, they leave behind noticeable bruises
or puncture marks and in soft foods, such as fruit,
marks are also preserved. The distinctiveness of the
bite mark is used for the identification of the person.
For example, gaps or abnormalities present in the teeth
of a suspect are compared with the bite mark to see
whether it is logical to say that the suspect's teeth
made the bite mark.
Bite
marks found on this apple are measured and recorded
for comparison. Photo courtesy of Dr
Berk.
|
|
| To be able to match a
suspect with a bite mark, the mark is documented using
photographs and in the case of food containing the mark,
it is alcohol or other preserving agents such as glycerol
and formaldehyde, which are used to preserve the
food. Then a record of the suspect's teeth is acquired,
where odontologists take an impression of the teeth in
silicon rubber. The impression left in the rubber is set
using plaster to make a replica of the gums and teeth
and compared with the samples. These photos and replicas
are then compared with the crime scene bite mark. The
forensic odontologist simply gives evidence as a witness
to injuries caused by biting and it is the method in which
they choose to present evidence in court that convinces
a jury whether a suspect guilty or innocent. |
|
|
|
|
