forensic odontogy.pptx

Forensic Odontology
Presenter
Dr. Surbhee Garg
Senior Resident
Dept. of Forensic Medicine and Toxicology
AIIMS, New Delhi
Moderator
Dr. Sudhir Gupta
Prof. & Head
Dept. of Forensic Medicine and Toxicology
AIIMS, New Delhi

Summary of Presentation
1. Historical Background
2. Dental examination
3. Personal Identification, Race, Sex, Age
4. Bite Marks
5. Identification from Dental DNA
6. Current practice in India
7. References

Introduction
• Forensic Odontology has been defined by Federation Dentarie
International (FDI) as “that branch of dentistry which,in the
interest of justice, deals with proper handling and examination of
dental evidence with proper evaluations and presentation of dental
findings.”
• Forensic dentistry- application of dental knowledge in
administration of justice.

History
• First dental identification was made in 66AD.
• During US revolutionary war, Paul Revere, helped identify casualties
by their bridgework.
• It was used on Adolf Hitler and Eva Braun at the end of world war II ,
World trade center blast in New York, Numerous airplane crashes and
mass disasters.
• Dr. Oscar Amoedo,1897, father of forensic odontology, 126 people
were charred to death in a fire accident in Paris.

Procedure of Examination
• Inspection:- oral hygiene, teeth,
gums, tongue, frenulum, buccal
mucosa, dental charting as per
eruption
status/decay/missing/broken,
stains or implants.
• Dental casts
• Radiological examination:-
Orthopentogram, CT scan

Radiological Examination
• Radiographs are helpful to determine the age of an individual by assessing the stage of
eruption of teeth.
• Skull radiographs can be used in the identification by superimposing on antemortem
radiograph or photograph. Since frontal sinuses are known for greatest normal variations
among individuals, they are used for this purpose.
• Radiograph should be taken before and after head and neck autopsy. Whenever possible,
radiograph should be made at the scene of accident or crime. They should be properly
labeled with identification number, site, and date of examination for future reference.

Types of Dental X-rays
• Bitewing X-rays show both the upper and lower back teeth in the
same photo.
• Periapical X-rays show the entire tooth, from the exposed top of
the tooth to the root and bone that supports the tooth.
• Occlusal X-rays show the top or bottom of the mouth, and help
find potential extra teeth, or teeth that have not yet broken through
the gum line.
• Panoramic X-rays show the entire lower jaw area, from the
sinuses to the nose to the jaw.

(a) A burned victim of a vehicle accident. (b) Antemortem upper left bitewing radiograph. (c) Postmortem upper
jaw panoramic reconstruction. (d) Postmortem lower jaw panoramic reconstruction. (e) Antemortem lower left
bitewing radiograph.

Dental CT
• A CT scan produces extremely detailed images of the body (or just mouth in
this case) by taking a 360-degree image of an area. A dental CT scan
creates a 3D image of dental structures, soft tissues, nerve pathways and
bone in just one scan.
• A traditional CT scan involves your entire body being placed into a large
tube to create the images. A dental CT scan is a little different. It’s called
a cone beam CT, where an X-ray beam in the shape of a cone is moved
around the patient to create the images. A dental CT scan emits a lot less
radiation than a traditional CT scan.
• The newer CT imaging based software called Dentascan (GE Health care,
UK) used for identification purpose. Using the Dentascan software,
reformatted panoramic images could be reconstructed for each case that was
compared to the ante mortem dental periapical radiographs, bite-wing films,
and panoramic radiograph.

• A reformated panoramic overview created by Dentascan delivers in a
non invasive way to overview jaws showing basic components of
teeth, (enamel, dentin, pulp) anatomic structures of alveolar bone
(mandibular nerve canal or floor of nasal cavity and maxillary sinus),
pathology (caries, radiolucencies, radio-opacities, or position of third
molars), and restorations.

Dental Cone-beam computed tomography
system.
The data obtained is used to
reconstruct a three-dimensional
(3D) image of the following
regions of the patient’s anatomy:
dental (teeth); oral and
maxillofacial region (mouth, jaw,
and neck); and ears, nose, and
throat

Benefits and Risks
• Fast, non-invasive
• Provide three-dimensional (3-D) information, rather than the
two-dimensional (2-D) information provided by A conventional
x-ray
• Radiation exposure are greater than conventional x-rays.

Dental examination is required for:
• Identification: Comparing antemortem (AM) & postmortem (PM) reco
rds
• burnt,mutilated, decomposing remains
• Estimation of age
• Race, occupation, sex
• Bite marks
• Diagnosis of poisoning
• Mass disasters

Personal Identification
• Traditional Methods: clothes, scar marks,moles,tatoos, personal
articles,finger prints, palatal prints etc.
• Principle of examining teeth:- Morphology and arrangement of teeth
vary from person to person.
• Fillingham and his coworkers , calculated that there are 1.8x 1019
possible combinations of 32 teeth being intact,decayed,missing or
filled.

Challenges with Dental Identification
• Absence of antemortem records
• Absence of acquired dental traits for identification
• Limitations of storing dental records for certain period
• Poor quality of dental records
• In Postmortem cases, all teeth may not be recovered as a result of
postmortem trauma.
• Fire can produce irreversible changes to restorations and teeth can
reduce the amount of available information comparison.

Ethnic origin ( Race )
• Scott and Turner suggested that the characteristic dental features
have evolved over time as a result of genetic and environmental
factors that have influenced different population groups( Caucasoid,
Negroid, Mongoloid)
• Dental features include:
1. Metric- tooth size and measurements
2. Non-metric- presence or absence of a particular feature. E.g
whether shovel shaped crown is present or absent .

Prominent labial marginal ridge (upper
incisor)-Mongoloid

(a) Prominent marginal lingual ridge (lower incisor).
(b) Prominent marginal lingual ridge (upper incisor)
seen in mongoloids

Shovel-shaped incisors(mongoloid)

In 87% of Caucasoid, the cusp of
Carabelli (chisel shaped) is seen

Sex Determination
• Craniofacial Morphology and dimensions- Skull and mandible
• Sex differences in tooth size- canine and molars
• Sex determination by DNA analysis- AMEL gene from ameleoblasts.
It is present on both the chromosomes- X and Y.

Age Estimation
• It is grouped in three phases.
1. Aging in prenatal,neonatal and early post natal
• Presence of neonatal line – indicates live birth
• Dry weight of mineralized tooth ( at 6th month IUL-60 mg, Newborn-
0.5 gms, 6th postnatal month- 1.8 gms )
• Teeth eruption patterns-Developmental stages of lower deciduous
first molar by Kraus and Jordan. The development is described in
ten stages denoted by Roman numerals from I to X; the IXth stage
includes three stages and the Xth stage includes five stages

Radiograph of upper and lower jaws of a fetus at the sixteenth
week of intrauterine life showing the initial mineralization of
deciduous incisors

2. Age estimation in children and
adolescents
• Eruption and calcification patterns
• Schour and Massler’s method
• Moorees, Fanning and Hunt method
• Demirjian’s method
• Nolla’s Method
• Value of 3rd molars

3. Age estimation in adults
• Gustafson's method
• Dentin translucency
• Age estimation from incremental lines of cementum
• Amino acid racemization- aspartic acid has rapid rate of racemization.
Also seen in root dentine( high )

• 1. Volume assessment of teeth:
• Pulp-to-tooth ratio method by Kvaal
• Coronal pulp cavity index.
• 2. Development of third molar:
• Harris and Nortje method
• Van Heerden system.

Using intraoral periapical radiographs
• Pulp-root length (R), pulp-tooth
length (P), tooth-root length (T),
pulp-root width at cemento-
enamel junction (A), pulp-root
width at mid-root level (C) and
pulp-root width at midpoint
between level C and A (B)
(Kvaal et al)

In Bekir Karaarslan et al,2010
• Study:- Retrospective study, the OPGs of 238 Turkish individuals of
known chronological age, ranging from 1 to 60 years, were measured.
Radiographs were evaluated by two independent dentists and age estimation
was achieved according to the decades.
• Results: The greatest accuracy in 1–10 years of age (89.6%), and the
greatest percentage of incorrect age estimations occurred in the range of 41–
50 years of age (41.7%). The correct age estimation percentage diminished
in the older age ranges.
• OPGs ---most reliable--- first decade of life.
• Unreliable --- fourth decade.
• The reliability of age estimation reduced in older age groups

Drawbacks of all these stagings
• The least amount of variation in development occurs least in the
younger age group but it increases with age.
• Do not have separate surveys for males and females each for all
the staging.
• Since regular secondary dentine is laid down at the pulpal end of the
primary dentine, the pulp cavity decreases in size with age. As
regular secondary dentine is deposited in larger amounts on the floor
of the pulp chamber than on the roof, some authors suggested that age
has a greater influence than attrition or irritation on secondary dentine
formation.

Bite Marks
• Bite mark analysis is an imperative area of forensic odontology and
considered the commonest form of dental evidence presented in the
criminal court. The process of comparing bite marks with a suspect's
dentition includes analysis and measurement of shape, size, and
position of an individual's teeth

Classifications of bite marks
1. Cameron and Sims Classification: based on type of agent producing
the bite mark and the material exhibiting it.
• Agents: human/animal
• Material: skin/body tissue/food items
2. Mac Donalds’ Classification:
• Tooth pressure marks
• Tongue scrape marks
• Tooth scarpe marks

Description
• Shape-
circular/elliptical/spherical
• Size
• Location/site
• Color
• Differentiate b/w tooth type
1. Incisors- rectangular
2. Canines-triangular
3. Premolar/molar- spherical

INCORRECT PLACEMENT OF ABFO SCALE
CORRECT PLACEMENT OF SCALE
INCORRECT PLACEMENT OF CAMERA IN REFERENCE TO
BITEMARK
CORRECT PLACEMENT OF CAMERA IN REFERENCE TO
BITEMARK

Other methods of analysing Bite Marks
1. Using comparison overlays with DentalPrint 3D Imaging Software
2. 3D/CAD supported Photogrammetry approach
3. Laser Scanning
Biting is a dynamic process comprising multiple component movements by the
perpetrator and the victim. Therefore, every episode of contact is a unique event, and
the same dentition can produce bite marks with variations in appearance. This is one
of the reasons for the complexity of bite mark analysis, and emphasizes the need to
apply objective techniques and incorporate.

Comparison overlays with DentalPrint 3D Imaging Software
Comparison overlays are obtained in four steps:
1.First, the teeth involved in the bite mark are selected from the 3D-scanned dental cast.
2.Second, a contact plane is created from the three highest points selected in areas defined in the 3D images of
the dental casts.
3.Then, biting edges are obtained from the 3D images of the dental cast. A variety of comparison overlays of a
single dental cast are generated.
4.Finally, biting edges from a 3D image of the dental cast are printed.
Effectiveness of Comparison Overlays Generated with DentalPrint Software in Bite Mark
Analysis
J Forensic Sci, January 2007, Vol. 52, No. 1

STEP 1: The teeth involved in the bite mark are selected from the 3D-scanned dental cast.
Comparison Overlays with DentalPrint 3D Imaging Software

STEP 2: a contact plane is created from the three highest points selected in areas defined in the 3D images of the
dental casts.

STEP 3: The biting edges are obtained from the 3D images of the dental cast.

STEP 4: The biting edges from a 3D image of the dental cast are printed.

Methods used in this approach:
1.Photogrammetric documentation and analysis process: The bite mark and the teeth of a suspect’s dental cast are
moved against each other arbitrarily on the screen in 3D, for comparison, measurement and to possibly establish
their congruence.
2.Case history
3.Digitising of the cast: The dental casts of suspects are digitised using a 3D surface scanner and directly
transferred into the 3D/CAD programme
4.Computer visualisation of the bite mark: The RolleiMetric multiple image evaluation system is used to calculate
the 3D data model of the bite mark and define the exact location of every given point in virtual space with an
accuracy of 0.1 mm.
5.3-Dimensional Analysis: The bite mark and the digitised casts of the suspects under evaluation are examined with
respect to matching shapes, angles and dimensions. The 3D/CAD programme allowed one to displace turn and
rotate the objects arbitrarily in order to fit and match them for possible congruence.
Bite mark documentation and analysis: the forensic 3D/CAD supported photogrammetry approach
Forensic Science International 135 (2003) 115–121
3D/CAD supported Photogrammetry Approach

Process 1: Photogrammetric documentation and analysis process
The maxillary and mandibular dental arches with a pattern of laceration at the front
part of the dental arches and lateral pattern of scratches and bruises. Reference
points (markers) and a solid scaled rule are used for the photogrammetric
documentation process to define measurement reference.
Data transformation of the photogrammetric bite mark documentation in the
RolleiMetric software system.

Process 3: Digitising of the cast
The dental casts of suspects (left side) were digitised using a 3D surface scanner. Data model of the cast at the
right image side.

Process 5: 3-Dimensional Analysis
The bite mark and the digitised casts of the suspects were examined with respect to matching shapes, angles and dimensions
in the 3D/CAD programme

• Laser scanning:
- The scanning system works on the principle of laser stripe triangulation.
- A laser diode and stripe generator projects a laser line onto the object to be scanned.
- The line is viewed at an angle by a camera, and height variations in the object are seen as
changes in the shape of the line.
- The resulting captured image of the stripe is a profile that contains the shape of the
object.
- The accompanying surface board uses digital signal processing to convert video data to
digital data to capture surface shape in real time at over 14,000 points per second.
- Either keyboard and mouse, or a foot pedal, drives the system.
3-D imaging and quantitative comparison of human dentitions and simulated bite marks
Int J Legal Med (2007) 121: 9–17

a. The FARO Gold Arm and ModelMaker H40
laser scanner used to digitise the study
dentitions and Hydroflex bite models and
b. a laser line generated by the ModelMaker
passing over the surface of a bite model.
The image is reflected back into the
ModelMaker’s camera to create the
resultant 3-D data set

Identification of Dental DNA
• Teeth is an excellent source of DNA
• Method of extraction- cryogenic grinding
• Types of DNA:
1. GENOMIC/NUCLEAR DNA
2. MITOCHONDRIAL DNA
PULP
DENTINE
CEMENTUM

Limitations of forensic odontology
• A study in Brazil reported -unsatisfactory results- due to lack of awareness,practical skills
of the forensic dentistry.
• In India, a 2016 survey by Navya and Raj showed that general dental
practitioners in Chennai have inadequate knowledge of and interest in forensic
odontology.
• A study by Preethi et al. in 2011. The 5-year gap between the two studies clearly
did not improve the situation in southern India.
• A study of dental practitioners in Pune, reflecting the situation in western India,
revealed inadequate clinical knowledge of forensic odontology, poor attitudes,
and lack of good practice related to record keeping.
• Moreover, a study that included purely practitioners, purely academicians, and
dentists with both roles showed that they had low levels of knowledge about the
routine application of forensic odontology, indicating the need to further educate
dental practitioners. Surprisingly, a study in Kanpur showed that practitioners had
adequate levels of knowledge and good attitudes, but low levels of good practice
regarding long-term dental record maintenance.

• Unlike countries US,UK,Australia, Dental records in india are
created and maintained to contribute to the safety and
continuity of dental care, for treatment decisions, treatment
planning, and not for legal purposes.
• For most who participate in the field of forensic odontology there is
not great financial reward, but the satisfaction of performing difficult
and challenging tasks well is immensely rewarding. A forensic
odontologist’s work can have great impact on the lives of individuals
and families.

References
1. Forensic Dentistry ,2nd Edition, CRC Press, UK
2. Matching simulated antemortem and postmortem dental radiographs from human
skulls by dental students and experts: testing skills for pattern recognition, J Forensic
Odontostomatol, 2010;28:1:5-12.
3. Individual identification by means of conventional bitewing film and subtraction
radiography. Forensic Science International 72 (1995) 55-64.
4. Role of Prosthodontist in Forensic Odontology, IJCDS, November, 2011;2(4), 85-89.
5. Fundamentals of Stereolithography, an Useful Tool for Diagnosis in Dentistry, Int. J.
Dent. Sc.,17(1),15-21.
6. Dental Age Estimation Methods: A Review, International Journal of Advanced Health
Sciences;1(12):19-25.

7. Bite mark analysis and comparison using image perception technology, A. van der
Velden, M. Spiessens, G. Willems, The Journal of Forensic Odonto-Stomatology, Vol.24
No.1, June 2006, 14-17.
8. Contribution of a Prosthodontist in the Field of Forensic Odontology, International
Journal of Prosthodontics and Restorative Dentistry, April-June 2014;4(2):56-59
9. Computed Tomography Use on Age Estimation in Forensic Dentistry: A Review, Journal
of Forensic Science & Criminology,2016;4(1):1-6.
10. Use of images for human identification in forensic dentistry. Radiol Bras.
2009;42(2):125–130.
11. Dental CT Imaging as a Screening Tool for Dental Profiling: Advantages and Limitations,
Forensic Sci,2006;51(1):113-119.

12. Effectiveness of Comparison Overlays Generated with DentalPrintr Software in Bite
Mark Analysis, J Forensic Sci, 2007;52(1):151-156.
13. Comparison of simulated human dermal bitemarks possessing three-dimensional
attributes to suspected biters using a proprietary three-dimensional comparison,
Forensic Science International 2009, 190:33-37.
14. Identification of a person with the help of bite mark analysis, journal of oral biology
and cranio facial research,2003;3:88-9 1.
15. An Overview of Bite mark Analysis, J Indian Acad Forensic Med, 2012;34(1):61-66.
16. Dental DNA fingerprinting in identification of Human Remains. 2010;2(2):63-68.

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