Abstract
It is well-known that dental evidence plays
a very important role in the identification
of unknown bodies. Of this evidence, X-ray
films are considered the most reliable and
valid dental evidence. On the other hand,
in recent years, digital X-ray photography
techniques have been developed and applied
in the field of clinical dentistry. We investigated
the application of the direct digital X-ray
system to dental personal identification
through the use of Compuray (Yoshida Dental
Trade Dist., co., Ltd.). The research results
can be summarized as follows:
1. We can easily obtain and maintain clear
digital X-ray images if compressed images
are transmitted through computer networks.
2. We can obtain same-angle X-ray images
as post-mortem dental evidence to ante-mortem
X-ray photographs on the monitor in a short
period of time through the use of Compuray.
3. The comparison between ante-mortem and
post-mortem X-ray images can be made easily
through magnification and superimposition.
4. As a result of the development of transportable
equipment, it is possible to conduct a detailed
comparison and examination in real time,
next to an unknown body.
In this time, we present two murder cases
using Compuray for personal identification
of victims.
CASE 1: On September 14, 1997, a dead body
of a female was found on a path in Chiba
Prefecture. As a result of judicial autopsy,
the cause of death was asphyxia by strangulation.
Although the body and clothes were intact,
because the postmortem interval was estimated
only several hours, due to the insufficient
information for any positive identification,
Chiba Prefectural Police Headquaters requested
a examination by dental findings to us. The
examination was carried out at soon, and
the X-ray examination was performed using
the Compuray beside the body. As a result,
we judged the body's age was 17(}1) years
old from calcification degree of unerupted
mandibular third molars and others.
CASE 2: On March 2, 1998, a human skull
has been found from a trolley-net of a fishing
boat, on the coastal waters of Japan, in
a 27.3 nautical miles from Inubosaki Lighthouse.
The skull has then been send to us from Japanese
Coastguard Choshi Division, to be checked
against the data of a specific person, who
has been claimed "missing" since
a month ago. Compared between the skull and
the dental ante-mortem X-ray films and records
supplied by the dentist of the person, we
have found many identical points between
the two, especially in regard to the X-ray
findings, which supported the idea that the
skull belongs to the missing person.
In the CASE 1, we have taken a total number
of about 20 digital images of different parts
of the remains from various angles. The direct
digital X-ray system has enabled us to get
all these pictures complete in just five
to six minutes. We have also taken, in the
CASE 2, a number of pictures from various
angles, all of which has been completed within
a remarkably short period of time.
Key words : Personal identification, Direct
digital X-ray system, Forensic odontology
