dealing with the proper handling, examination & evaluation of dental evidences and with the proper presentation of dental findings in the interest of justice.

1. By Muhammad Awadine
Oral Biology Department
Forensic
Dentistry

2. • The branch of dentistry which deals
with the proper handling, examination
& evaluation of dental evidences and
with the proper presentation of
dental findings in the interest of
justice.

3.  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.
 Most people have dental Records, or these can be created through making a dental
impression from a suspect.
 These can then be COMPARED to either teeth found on a dead body or bite marks
found at the scene of a crime.
 It relies on sound KNOWLEDGE of teeth and jaws, possessed by dentist and
incorporates dental anatomy, histology radiography, dental materials and
developmental anomalies of dentition.
 The INTRPRITATION of dental evidence is a specialist task, undertaken by a
forensic dentist who may be called as an expert witness in a case.

4. The earliest known identification from teeth is in 1775 by
Paul Revere. – Paul Revere made a silver bridge for one
man. The man was killed in the War. – Body was in mass
grave and identified by his silver dental work.
1837- Dr Edwin Saunders established the eruption
sequence.
1897- Dr Oscar Amoedo ( father of forensic odontology )
wrote the first book of forensic dentistry.

6. 1-Dental identification.
2- Bite marks investigations.
3- Analysis of dental malpractice.
4- oral evaluation of child abuse.
5- Presenting evidence in court as an expert
witness.

7. Decomposing remains.
Skeletonized remains.
Charred remains.
Intact remains without any putative victim.
Multiple bodies recovered from a common
location.
Mass disaster.

8. 1. Stable & durable (tooth material & restorative materials) – Teeth are
the most durable organs in the body and can be heated to temperature
of 1600°C without appreciable loss of micro structure.
2. Uniqueness (size/shape/pattern/wear/repair) – The 16 missing teeth
can produce is approximately 600 million different number of
combinations . Four missing and four filled teeth in a mouth combined
can produce more than 700 million combinations. Although teeth are
relatively resistant to environmental insults after death.
3. Previous records
4• Since teeth can resist extreme conditions, they are the excellent source
of DNA.

9. 1- Comparative identification.
2- DNA identification.
3- Edentulous identification.
4- Dental Profiling.

10. 1. Oral autopsy
2. Securing ante-mortem records
3. Comparison
4. Writing the final report and drawing
conclusions

11. Oral examination is an essential part of post-mortem
procedure.
Thorough examination of soft tissue injuries, fractures and
presence of foreign bodies is undertaken and samples of hard
and soft tissues may be obtained for further investigations.
All this information is entered on to the standard “Interpol
postmortem form” which is color coded in pink.

12. Dental records contain information of treatment and
dental status of a person during his/her lifetime.
Such records may be in the form of dental charts, radio
graphs, casts and/or photographs.
The contents of all available dental records should be
transcribed onto the standard “Interpol ante-mortem
form” which is color coded in yellow.

13. Parameters to be compared
1. Teeth.
2. Prosthetic appliance– bridges,
partials, crown, false teeth.
3. Shape, form (morphological)
features.
4. Genetic anomalies.

14. A detailed report and factual conclusion, based on comparison,
must be clearly stated.
Acharya and Taylor have suggested a range of conclusions,
which include:
1. Confirms Identification
2. Probable Identification
3. Possible Identification
4. Insufficient Information
5. Excludes Identification

15. Since teeth can resist extreme conditions, they are the
excellent source of DNA.
This facilitates comparison with the known biological ante-
mortem sample of the person such as hair, epithelial cells
from a tooth brush or a biopsy specimen.
If the person’s ante-mortem sample is unavailable, the
DNA pattern may be compared to a parent or a sibling.

16. Useful in edentulous persons
Rugae patterns like teeth are considered
unique to an individual
Rugae patterns on the decedent’s maxilla
or maxillary dentures may be compared
to old dentures that may be recovered
from the decedent’s residence or plaster
model from dental office.

17. RUGAE
PRIMARY RUGAE (>5mm)
SECONDARY RUGAE(3- 5mm)
FRAGMANTARY RUGAE (2-3mm)
OR -BRANCHED -UNIFIED -
CROSS-LINKED -ANNULAR -
PAPILLARY

18. Dental profiling includes extracting a triad of
information-the decedent’s ethnic origin,
gender and age.
The information from this process will enable a
more focused search for ante-mortem records .

19. Anthropologists have divided race into following broad groups-
(i) Caucasoid (ii) Negroid (iii) Mongoloid
 (iv) Eskimos (v) American Indians.
Dental features used to describe population differences are
broadly categorized as metric (tooth size) and non metric
(tooth shape).
Metric features are based on measurements and non metric in
terms of presence or absence of a particular feature , e.g:
whether carabelli’s cusp is present or absent.

20. Metric Features
Size of teeth: Both deciduous and permanent dentitions are
considered.
The size of the teeth varies in different races
 Larger teeth are seen in Australian, South American Indian tribes.
 Lateral incisor is relatively large compared to central incisor in
mongoloids.
Intermediate sized teeth are seen in Taiwanese Aborigines and
Australian whites respectively.

21. Gender can be determined based on data from
Cranio-facial morphology and dimensions
Sex differences in tooth dimensions
Tooth morphology
Sex determination by DNA analysis
Amelogenin (AMEL) is one of the major matrix proteins secreted by the
ameloblasts of the enamel.
The AMEL gene, coding for a highly conserved protein, is located on X-
and Y chromosomes in humans.
Thus the females (XX) have two identical AMEL genes but the males (XY)
have two non identical genes.

22. Mandibular cuspid shows the maximum sexual dimorphism-
Mesio-distal diameter < 6.7 mm (in females)
Mesio-distal diameter > 7 mm (in male)
Root length of maxillary cuspid is >3 mm more in males than
females.
Distance b/w tips of coronoid processes(cm) x distance b/w angles
of jaw
if > 90 ; then male ,if < 78 ; then female

23. *Dental age estimation makes use of morphologic,
radiographic, histologic, and biochemical methods to
examine the age dependent changes in teeth.
It is grouped into three phases:
1. Ageing in prenatal, neonatal and early postnatal.
2. Age estimation in children and adolescents.
3. Age estimation in adults.

24. 1. Utero ( from 16 weeks) to eruption of 1st tooth at 6 months.
2. Primary dentition (milk teeth): from 6 months to 6 years.
3. Mixed dentition: 6 to 12 years.
4. Permanent dentition: From 12 years on

25. *Presence of neonatal line indicates a live births
Histological examination is more precise in neonatal age
estimation than radiography.

28. (A) Last erupted tooth—21; approximate dental age = 7–8 years; (B) Last erupted tooth—31, 41; approximate
dental age = 6–7 years; (C) Erupting teeth—13; approximate dental age = 11–12 years;
(D) Erupting teeth—25 and 13; approximate dental age = 10–12 years

29. * This method is based on morphological and histological changes of the teeth.
* • This assessed regressive changes such as:
* a) Amount of occlusal attrition(A)
* b) Coronal secondary dentine deposition(S)
* c) Loss of periodontal attachment(P)
* d) Cementum apposition at the root apex(C)
* e) Root resorption at the apex(R)
* f) Dentine translucency(T)
* An+ Sn+ Pn+ Cn+ Rn+ Tn = X; a total score
* •Age was estimated using the formula Age = ( 11.43 + 3.63X ) years
* •It was found that an increase in the total score corresponds to an increase in age

30. *Regressive changes
*• For each of these regressive changes or variables, different
scores ranging from 0-3 were assigned.
*STAGE 0 – indicates no change
* STAGE 1 – beginning of change
*STAGE 2 – obvious change
* STAGE 3 maximum change

31. * Attrition (A)
* A0—no attrition
* A1—attrition limited to enamel level
* A2—attrition limited to dentine level
* A3—attrition up to pulp cavity
* Secondary Dentin (S)
* S0—no secondary dentin formation
* S1—secondary dentin up to upper part of pulp cavity
* S2—secondary dentin up to 2/3rd of the pulp cavity
* S3—diffuse calcification of entire pulp cavity
* Periodontal Disease (P)
* P0—no obvious periodontal disease
* P1—beginning of periodontal disease but no bone loss
* P2—periodontal disease more than 1/3rd of the root
* P3—periodontal disease more than 2/3rd of the root

32. * Root Translucency (T)
* T0—no translucency
* T1—beginning of translucency
* T2—translucency more than 1/3rd of the apical root
* T3—translucency more than 2/3rd of the apical root
* Cementum Apposition (C)
* C0—normal cementum
* C1—thickness of cementum more normal
* C2—abnormal thickness of cementum near the apex
of the root
* C3—generalized abnormal thickness of cementum
throughout the apex of the root
* Root Resorption (R)
* R0- no resorption
* R1- apical 1/3rd root resoption
* R2- apical 2/3rd root resorption
* R3- comlete root resorption

33. *Bang and Ramm were the first to use
dentine translucency alone for estimating
age.
* • Root dentine starts to become
translucent during the third decade (30s)
of life beginning at the apex and
advancing coronally.
* • Root dentin starts to become
translucent due to the increased
intratubular calcification.
*• Therefore dental root translucency
increases with advancing age.

34. *All amino acids (except glycine) are optically active, having a
stereocenter at their α-C atom.
* This means that the amino acid can have two different
configurations, "D" or "L" which are mirror images of each other.
*Living organisms keep all their amino acids in the "L"
configuration.
*When an organism dies, control over the configuration of the
amino acids ceases, and the ratio of D to L moves from a value
near 0 towards an equilibrium value near 1, a process called
racemization.
*Thus, measuring the ratio of D to L in a sample enables one to
estimate how long ago the specimen died.
*

35. *
*Helfman and Bada first suggested a relationship between
dentinal age and the extent of aspartic acid racemisation in
dentine.
*• The extent of racemization of aspartic acid in coronal dentin
of normal permanent teeth can be used to estimate the age of
an individual at the time of death.
*• This method is accurate with age estimates within plus/minus
three years of actual age.

36. * Some other techniques of age determination..
* 1. Pulp diameter to crown diameter ratio and
* pulp / root length, pulp /root width was
measured.
* 2. An interesting method using intensity of
fluorescence in dentin and cementum, which
shows strong correlation between age, deepening
of colour of the tooth and increase in intensity of
fluorescence. The colour changes in the
cementum and dentin are caused by infusion of
decomposition products from erythrocytes.
* 3. The incremental lines of cementum will help to
determine the age of adults. A major
disadvantage of this method is the necessity to
extract or section the tooth. It is not practical
among living individuals.

39. *The shape or curvature
* No. of tooth marks
* Horizontal diameter
* Vertical diameter
*Depth of depression
*Distances between two teeth
*Orientation of each tooth

41. *Cutaneous bitemarks represent
patterned injuries in skin produced by
teeth.
*May be inflicted by humans or animals
(most commonly by dogs and cats); may
be on tissue, food items or other
objects.
*• Human bite broad, U-shaped
somewhat circular or oval.
*• Animal bite narrow in the anterior
aspect , V shaped and elongated also
morphology of the teeth is different.

42. *The Concept
• Each human dentition is unique,
differing even in identical twins.
*For this reason, bite marks have
been referred to as “dental
fingerprints”.
*Diagrammatic depiction of human
bite mark showing typical pattern
of contacting surfaces of teeth
*• Is composed of two separate,
curved arches facing one another.
*• Each arch is composed of a row of
contusions, abrasions, lacerations
or depressions approximating the
size & shape of biting surfaces of
human front teeth.

43. Typical presentation of bite mark injuries
• A representative human bite is described as
an elliptical or circular injury that records the
specific characteristics of the teeth
• 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.
• This extra-vascular bleeding is caused by
pressure from the teeth as they compress the
tissue inward from the perimeter of the mark.
Class features: Incisor=rectangular
Canines=triangular or rectangular Premolars
and molars= spherical or point shaped
Individual features: Rotation, Dental work,
diastema, fracture etc.

44. A. Cameron and Sims Classification
1. Causing Agents
i-Humans
ii–Animals
2. Substrate Materials -Skin , body tissue
i-Food stuff
ii-Other materials
B. Mac Donald’s classifications
I -Tooth pressure mark
Ii -Tongue pressure mark
Iii -Tooth scrape mark
C. Based on severity of injury
a. hemorrhage -- small bleeding spot
b. abrasion -- undamaging mark on skin
c. contusion -- ruptured blood vessel, bruise
d. laceration -- punctured or torn skin
e. incision -- neat puncture of skin
f. avulsion -- removal of skin

45. I- Bite mark evidence collection from the victims Steps:
1.Visual examination.
2.Photography -Orientation photographs -close-up photographs.
3.Saliva swab: -WBC and sloughed epithelial cells, potential source
of DNA.
4.Impression: Vinyl polysiloxane, dental acrylic & plaster.
II- Evidence collection from suspect using a signed and informed
consents or a court order (warrant) also include:
1-photograph.
2-two casts.
3-bite registration in centric occlusion.
4-saliva swab from buccal vestibule.

47. • Physical characteristics to be studied are:
1- Distance from cuspid to cuspid
2– Tooth alignment
3– Teeth width, thickness, spacing
4– Missing teeth
5– Wear patterns including chips and grinding
6– Dental history including fillings, crowns, etc.

50. I- Positive bite-mark
•An injury showing a pattern that may or may not be caused by
teeth; could be caused by other factors but biting cannot be ruled
out.
II- Possible bite-mark
•The pattern strongly suggests or supports origin from teeth but
could conceivably be caused by something else.
III- Definite bite-mark
•There is no reasonable doubt that teeth created the pattern;
other possibilities were considered and excluded.

52. *Malpractice suit claims -Alterations of
face , jaw , or chin -Unnecessary dental
work -Careless/improper dental work.
*Role of Forensic dentist
• Examines dentition & oral tissues to
establish degree of trauma , its possible
cause and its potential impact on ability
to chew food properly
•Present testimony regarding their
findings

53. Child Abuse

54. *Multiple broken, discolored, missing or
avulsed teeth.
* Repeated episodes of mouth trauma
Peculiar malocclusions & non occluding
jaw segments.
* Healed jaw fractures which were
displaced Laceration of labial or lingual
frena Forceful lip pulling or slapping.
* Isolated laceration of soft palate
Insertion of utensils during forced
feeding.
* Horizontal abrasions or contusions
extending from lip commissures.
*adult bite (anger biting).
*Rampant caries/Nursing Bottle
Syndrome.

55. FORENSIC DENTIST AS AN
EXPERT WITNESS
• FREQUENTLY CALLED IN TO GIVE
SWORN TESTIMONY IN COURTROOMS
IN VARIOUS CASES SUCH AS:
* DENTAL IDENTIFICATION
* BITE MARK ANALYSIS
* AGE ESTIMATION
* CHILD ABUSE CASES
* DENTAL FRAUD etc.

56. Shortcomings of dental identification :
*• Difficult to locate than fingerprints
*• Records may be inadequate
*• No standardization of dental records (no recognized
minimum no. of concordant features required for
positive identification)
* • Written entries are subject to error
*• Alterations (decayed , filled or extracted) after the last
ante-mortem entry