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Forensic Dentistry
What is Forensic Science?
• …the application of
science to those
criminal and civil laws
that are enforced by
police agencies in a
criminal justice
system.
Forensic Science is…
• Applied science
• Often called
“criminalistics”
Forensic Science applies
•
•
•
•
Chemistry
Biology
Physics
Geology
to civil and criminal law.
Definition of Forensic
Dentistry
Forensic dentistry, or forensic
odontology, is the application of
dental and paradental
knowledge to the solution of
legal issues in civil and in
criminal matters.
The THEORY behind forensic
dentistry is that no two mouths are
alike (even identical twins are
different), and that teeth, like tools,
leave recognizable marks.
Identification by teeth is not new.
Identification by teeth is not new.
During the U.S. Revolutionary War, none other
than Paul Revere (a young dentist) helped identify
war casualties by their bridgework.
Teeth are highly resistant to destruction and
decomposition, so dental identification can be made
under extreme circumstances.(1600ºC)
It was used on Adolf Hitler and Eva Braun at the
end of World War II, the New York City World
Trade Center bombing, the Waco Branch Davidien
siege, and numerous airplane crashes and natural
disasters.
Forensic Dentistry involves
•Identification of the living or the deceased
•Bitemark identification, analysis and comparison
•Lip print identification, analysis and comparison
•Rugae print identification, analysis and comparison
•Patterned injury identification, analysis, comparison
•Identification of dental specimens at crime scene or
elsewhere
•Evaluation of oro-facial trauma
•Malpractice and negligence claims
Who is this??
Means of Identification
•TEETH : natural and synthetic (fixed and removable)
•BONE : trabecular pattern, toris and osseous anomalies
•PRESENCE OF FOREIGN BODIES : implants,
unretrieved amalgam particles, surgical instruments,
bullets, fragments of various origins
•SINUS CONFIGURATION : maxillary and frontal
•SKULL SUTURES
•SOFT TISSUE FEATURES : rugae (rugoscopy) and lip
(cheiloscopy, quieloscopy) prints
•PHOTOGRAPHIC COMPARISON : Facial or dental
superimposition or approximation
•DNA
There are 2 types of dental identification team
organizations:
Traditional: its usually community based is often lead by
chief forensic dentists, & includes dentists hygienists &
dental assistants.
Disaster Mortuary Operational Response Team
(DMORT) system…consists of:
Dental team
Forensic pathology team
Anthropology & laboratory support
Photography & communication support.
Logistics team
Mortuary science team
Possible methods for identification of bodies are:
1. Visual recognition;
2. Property identification;
3. Scientific identification:
•finger prints;
•dental comparison;
•Medical evidence.
Dental comparison
Dental comparison affords a potentially straightforward
& simple means of establishing identity.
This method of identification depends upon:
•The relative resistance of mineralized dental tissues &
dental restorations to changes resulting from decompositions
or harsh environmental extremes such as conditions of
temperature & forces;
•The unique individual characteristics of dentition the
dentition & dental restorations.
•The availability of documentation of the ante-mortem status
of the dentition in form of dental treatment records &
diagnostic radiographs.
Dental comparison
Identification is achieved by comparing
dental status of deceased with the dental
records of the person known or suspected
to be missing in circumstances consistent
with those in which the remain of the
unknown, deceased person were found.
Obviously, the greater the number of
coincident features, more reliable will be
the identification.
Age Estimation
Age estimation is commonly the
purview of the forensic
anthropologist using the pubic
symphysis, innominate auricular
surfaces, carpal bones, sternal rib
ends, cranial suture closure and
long bones.
Age Estimation
However human age can also be
estimated in living or deceased
individuals by
•examining teeth eruption patterns,
•third molar development, and
• translucent dentin development in
intact and sectioned teeth.
Age Estimation
In living individuals, anthropologic
age determinants other than wrist
radiographs are not possible, so
dental age estimation can be
valuable. In deceased individuals
there may be no skeletal evidence
other than dental structures or teeth
to make an age estimation.
Age Estimation
You can also tell age solely by analysis
of teeth -the Gustafson method (looking for six
signs of wear)
or
the Lamendin method (looking at
transparency of roots).
The criteria that are mostly used in forensic
odontology to determine age include:
•Eruption of teeth
•Resorbtion of roots
•Attrition
•Root transparency
•Dental pathology such as caries
•Periodontal diseases
Age Estimation
All dental records are based on a universal numbering
system, and contain an amazing amount of information.
For example, they note:
1. fillings
2. extractions
3. surface structure/root configuration
4. adjacent teeth
5. twisted/tilted teeth
Antemortem/Postmortem
match determines identity.
INDIVIDUAL AGE ESTIMATION
BASED ON D-ASPARTIC ACID AND
D-GLUTAMIC ACID CONTENT OF
THE TEETH
J. Csapo, Zs. Csapo-Kiss (University of Kaposvar, Faculty of Animal
Sciences, Department of Biochemistry and Foodstuff Chemistry, H-7400
Kaposvar, Guba S. u. 40. Hungary)
Facial reconstruction
Artist’s rendering may hold key to
solving mystery of unidentifed man
Definitions of marks made by human teeth:
Tooth mark: mark left by tooth (human or non-human)
Arch mark: mark produced by four or five adjacent
teeth & same arch
Bite mark:
:a mark made by teeth either alone or in
combination with other mouthparts (Mac Donalds,
1974)
: Tooth mark produced by antagonist teeth
(Jacobson & Keiser-Nielsen 1981)
Bite mark comparison is fairly new, however, going
back to the mid-1970s. Police investigators have always
noticed that at some crime scenes, criminals seem to
leave their bite impressions on food products, chewing
gum, or more commonly on the skin of their victims,
especially in cases of battery, rape, child abuse, and
homicide.
BITE MARKS
There are seven (7) types of bite marks which can
be classified by four (4) degrees of impression:
1. hemorrhage -- small bleeding spot
2. abrasion -- undamaging mark on skin
3. contusion -- ruptured blood vessel, bruise
4. laceration -- punctured or torn skin
5. incision -- neat puncture of skin
6. avulsion -- removal of skin
7. artifact -- bitten-off piece of body
1. clearly defined -- significant pressure
2. obviously defined -- first-degree pressure
3. quite noticeable -- violent pressure
4. lacerated -- skin violently torn from body
Possible Bitemark: An injury showing a pattern
that may or may not be caused by teeth; could e
caused by other factors but biting cannot be
ruled out.
• criteria: general shape and size are present but
distinctive features such as tooth marks are
missing, incomplete or distorted or a few marks
resembling tooth marks are present but the arch
configuration is missing.
Probable Bitemark: The pattern strongly suggests
or supports origin from teeth but could conceivably
be caused by something else.
• criteria: pattern shows (some) (basic) (general)
characteristics of teeth arranged around arches.
Definite Bitemark: There is no reasonable doubt that
teeth created the pattern; other possibilities were
considered and excluded.
• criteria: pattern conclusively illustrates (classic
features) (all the characteristics) (typical class
characteristics) of dental arches and human teeth in
proper arrangement so that it is recognizable as an
impression of the human dentition.
BITE MARKS
contusion
Typical presentation of bitemark injuries
•Females are most often bitten on the breasts
and legs during sexual attacks,
•whereas bites on males are commonly seen
on the arms and shoulders.
•A representative human bite is described as
an elliptical or circular injury that records
the specific characteristics of the teeth
Typical presentation of bitemark injuries
•The injury may be shaped like a doughnut with
characteristics recorded around the perimeter of the
mark.
• Alternatively, it may be composed of two U-shaped
arches that are separated at their bases by an open space.
•The diameter of the injury typically ranges from 25-40
mm.
•Often a central area of bruising can be seen within the
marks from the teeth. This extravascular bleeding is
caused by pressure from the teeth as they compress the
tissue inward from the perimeter of the mark.
Typical presentation of bitemark injuries
Many times the bite marks are obvious, but at many
other times bite marks are very faint or even invisible.
In such cases we flash a special light on the dead body.
This is called ultra violet light or UV light.
Human saliva shines brightly in UV light. Wherever
the attacker has bitten his victim, his saliva stains are
bound to be there, although they may dry.
These saliva stains start shining and we can
immediately know that this is the place where bite
marks are present.
Documentation of Bite mark
Make a record of the injury,
•
including descriptive,
•
narrative notes that document the physical
appearance,
•
colour, size and orientation of the injury.
What is the location on the body?
What is the relative contour and elasticity of the site?
Can the difference between marks from the upper and
lower teeth be determined?
What types of injuries are present? Cuts? Bruises?
Scrapes?
Saliva swabs for diagnosis
Use the double swab technique:
first, a cotton swab moistened with distilled water is
employed to wash the surface that was contacted by
the tongue and lips using light pressure and circular
motions.
Then, a second swab that is dry is used to collect the
remaining moisture that is left on the skin by the
first swab.
Both swabs are thoroughly air-dried at room
temperature for at least 45 minutes before they are
released to police authorities for testing.
Saliva swabs
•The two swabs must be kept cool and dry to reduce the
degradation of salivary DNA evidence and the growth of
bacteria that may contaminate the samples and reduce
their forensic value.
•Then they should be submitted to the laboratory as
soon as possible for analysis.
•If the time until submission is protracted, it is
recommended that the swabs be stored in a paper
evidence envelope or box that will allow air to continue
to circulate around the swab tips. (The swabs should not
be sealed in plastic bags or plastic containers.)
•The envelopes or boxes should be refrigerated or frozen
during storage.
D NA
•A DNA sample must also be collected from the
victim at this time to provide the opportunity for
comparison with the sample from the bitemark.
•This sample could consist of a buccal swab or a
sample of whole blood.
•The victim's DNA profile will enable analysis of
any mixtures that are found in the sample from
the bite, which may involve contributions from
the depositor and the victim.
Impression
•Fabricate an accurate impression of the bitten
surface to record any irregularities produced by the
teeth, such as cuts, abrasions, etc.
•Use vinyl polysiloxane, polyether or other
impression material available in the dental office
that is recommended for fixed prosthetic
applications.
•Dental acrylic or plaster can be used as a rigid
support for the impression material. This will
allow the impression to accurately record the
curvature of the skin.
First aid
Prompt medical attention should be
provided for the living victim since
human bites have a higher potential for
infection than animal bites.
Injuries that disrupt the integrity of the
skin's surface should be treated as soon
as possible.
Phases of forensic identification:
Preliminary Evaluation:
•Nature of death
•Reason of dental input
Phase 1 Postmortem Exam:
•Facial & intraoral photograph
•Oral structures
•Radiographs
•Dental impressions
Phase 2 Data collection & ante-mortem investigation:
•All available dental records
•Original radiographs
•Dental models
•Cephalometric films
Phase 3
Comparison & conclusion:
•All postmortem & ante-mortem information
obtained & charted
•Results compared
•Conclusion reached
Phase 4
Procedure in dental identification:
Recovery of dental structures;
Reconstruction & examination;
Collection of ante-mortem records;
Transcription of dental records;
Comparison of odontograms;
Report
HOW FORENSIC DENTISTRY WORKS
medical examiners or police investigators.
discovered a bite mark while conducting an
autopsy or viewing the body at a crime scene.
A linear (ABFO) scale should be placed somewhere in the
called
photograph. AForensic
camera angledentists
of 90 degrees
is best for a flat
surface, while a 40 degree angle causes 25% distortion of
a bite mark.
bite mark can be photographed or even excised
….HOW FORENSIC DENTISTRY WORKS
obtain a saliva sample from the bite.
Next, the forensic dentist makes multiple
impressions, casts, or molds of the bitemark, and
has access to a variety of materials in which to
choose the right gum, rubber, plastic, or powder
to make a cast.
….HOW FORENSIC DENTISTRY WORKS
Some forensic dentists used the Dorion method,
which advocates the removal of bitten tissue for
microscopic examination. Others use advanced
techniques such as scanning electron
microscopy, computer-enhanced digitization,
and xeroradiology. Computerized bite analysis
software also exists.
HOW FORENSIC DENTISTRY WORKS
Once a suspect is apprehended, the forensic
dentist makes one or more impressions of the
suspect's teeth, comparing them to the recorded
bite marks, and if called to testify, renders an
opinion of the probability of a match.
CONCLUSION
•Bitemark is not an accurate representation of the teeth.
•A lot depends on the mechanics of jaw movement and
use of the tongue.
•Inside the mouth, the lower jaw (mandible) is movable
and usually delivers the most biting force.
•The upper jaw (maxilla) is stationary, holding and
stretching the skin, but when skin is ripped or torn, the
upper teeth are involved more deeply.
•Most bitemarks usually show a curvature where the
upper teeth, at least, made an impression.
CONCLUSION
•The skin is elastic, tending to slip along the upper teeth
until it catches hold.
•Depending upon the type of victim, some bitemarks last
for hours and others for days, but almost all bitemarks
alter themselves as time elapses.
•Photographing bitemarks at intervals over a set period
of hours or days is part of the standard protocol
recommended by the ABFO.
•Bitemarks also change or become distorted when the
posture of the victim changes, so the forensic dentist
might be able to assist with determination of how the
perpetrator moved the body.
P r o b l e m s in i d e n t i f i c a t i o n :
•Condition of material recovered;
•Errors in examination;
•Inadequate ante-mortem data.
Summary
Conclusions from the analysis of bitemark
evidence can assist the justice system to
answer crucial questions about
interactions between people at the scene of
a crime.
Willingness by dentists to recognize, collect
and preserve this evidence can be
invaluable in the resolution of heinous
interpersonal crimes.
Sounds interesting, doesn't it?
If you can do it, it means you have
the traits of a good detective.
All the best!
REFERENCES
Rothwell BR. Principles of dental identification
Dent Clin North Am 2001; 45 (2): 253-270
Brown KA (1982) identification of linda Agostini
American Journal of forensic Medicine & Pathology 3,
131-141.
Oral Care Report (The Colgate), Providing Continuing
education as a service to dentistry world wide, Vol 12,
Nov 2, 2002.
Prabhu, Wilson Daftarey. Diseases of Tropics. Forensic
Odontology.
REFERENCES
G Gustaffson forensic odontology .staple press.
1966.
Nivelle Damm allen Bouquet. Oral & maxillofacial
Pathology 2nd Ed.
REFERENCES
Furness J. A general review of bite-mark evidence. Am J Forensic Med
Pathol 1981; 2: 49-52
Webb D A, Pretty I A, Sweet D. Bitemarks: a psychological approach.
Proceedings of the American Academy of Forensic Sciences Reno, NV,
February 2000; 6: 147.
Vale G L. Dentistry, bitemarks, and the investigation of crime. J Calif
Dent Assoc 1996; 24: 29-34.
Tsang A, Sweet D. Detecting child abuse and neglect - Are dentists doing
enough? J Can Dent Assoc 1999; 65: 387-391.