Various Samples used in Forensic Odontology

1. VARIOUS SAMPLES USED IN
FORENSIC ODONTOLOGY
PRESENTED BY :-
ALISHA KARMALI

2. • Why Teeth?
I. Each individual has individual set of teeth which can
be traced back to establish dental records.
II. Teeth are a source of DNA, dental pulp or crushed
tooth can provide nuclear or mitochondrial DNA to
help identify that person.

3. • When is Dental Identification used?
I. To identify human remains that cannot be identified
using face recognition, fingerprint or other means.
II. Identify bodies in mass fatalities (e.g. plane crashes)
III. Determine the source of bite mark injuries (assault
or suspected abuse – sexual assault, child abuse,
personal defense situations)
IV. Estimate age and sex of skeletal remains.
V. Testify in case of dental malpractices.
VI. Other methods – Cheiloscopy (study of lip prints),
Rugoscopy (study of palate rugae patterns),
Sialochemistry (detection of chemicals in saliva).

4. • Post Mortem dental profiling :-
I. It includes descendants – ethnic origin, gender, age.
II. Race Determination (country of residence) –
Treatment quality.
III. Sex determination – teeth are generally smaller in
females (mesio-diatal and bucco-lingual dimensions).
Canines show max. sex difference- being larger in
males.
• By DNA analysis – Y chromosome from dental pulp
after 1yr of death. From Amelogenin – enamel
protein located on X and Y chromosome. Barr bodies
and x-chromosome of female detected on buccal
mucosa epithelium.

5. • Identification from Dental DNA :
Teeth – Excellent source of DNA
PCR (polymerase chain reaction) – amplifies highly
degraded DNA.
Types of DNA-
1. Genomic or Nuclear DNA (commonly used)
2. Mitochondrial DNA

6. •Extraction of Dental DNA :-
CRYOGENIC GRINDING – Coding the whole tooth to
extremely low temperature using liquid nitrogen and
grinding to fine powder.
Less destructive method is drilling the root canals and
scrapping pulp area.

7. • Bite Marks :-
Impression from teeth found on skin or items left in the
scene – outline teeth placement.
Bite marks are photographed with scale. Cast
impression is taken. Impression traced on transparencies.
Casts of suspects teeth are taken. Comparison between
suspects teeth and bite mark.
Site of bite marks -
• Females – breasts, legs (sexual assault)
•Children – genitals, oral-, para- oral regions (child abuse)
•Males- fingers, arms, shoulders (fight)

9. • Computer Odontology -
I. Automatic dental code matching – bites run through
search to find a match
II. Odontosearch – compare on bases of missing
peoples.
III. Automatic dental identification system – list of
people who have the same dental code number.
IV. 3D bite mark analysis – used to generate overlays
with various pressure and deviations. Overlays
compared with bite marks.

10. • Saliva :-
It is a major source of DNA because it cantains sloughed
epithelial cells from oral mucosa and inner surface of lips.
Enzymes present in saliva and teeth – Streptococcus
Salivaricus
PCR provides means to identify the bacterial composition
from bite marks and can be matched exclusively to those
from the teeth responsible.

11. Blood :-
• Red blood cells do not have any DNA, as they lose their
nuclei (the compartment in a cell that contains the DNA)
as they mature.
• So the DNA in your blood is in your white blood cells. To
get at it, scientists first spin a small sample of your blood
at high speed, to separate the cells from the blood fluid.