The different use of Dental aids in forensics

1. Forensic Odontology
Dr.Adharsh

2. Introduction
• When the subject of forensic dentistry arises, the first reaction
tends to be towards one of the two extremities: either very cool
or decidedly gross. The public assumption seems to be that
forensic dentistry deals with “the dead”. Well this view is not
totally inaccurate.
• The word ‘forensic’ comes from the latin word ‘forum’
meaning the court of law.

3. • FDI defines forensic odontology as “that branch of dentistry,
which in the interest of justice, deals with proper handling of
dental evidence, and with proper evaluation and presentation
of dental findings.”

4. History of forensic odontology
• The oldest known example of the identification of an individual
confirmed by teeth was reported by the Roman historian
Cassius Dio (c. 165–c. 235 A.D.). Aggripina the Younger, wife
of Emperor Cassius and mother of future Emperor Nero,
contracted for the killing of a perceived rival, Lollia Paulina.
In his account Dio reported, “She did not recognize the
woman’s head when it was brought to her; she opened the
mouth with her own hand and inspected the teeth, which had
certain peculiarities.”

5. • 1776. Boston. First forensic dentistry in American history. Paul
Revere ID’s General Joseph Warren, a distinguished physician, who
was killed during the Battle of Bunker Hill. The British stripped the
body and buried it. The General’s body was later ID’d by Revere by
means of a dental prosthesis which he had previously adjusted.
• 1945. Berlin. Adolph Hitler and Martin Bormann were ID’d on
dental evidence and still considered to be the most high profile
case of dental identification

6. • 1996. TWA flight 800 crashes into ocean off New York coast.
Dental ID’s utilized.
• 2000. Alaska Airliner crashes in ocean near Ventura. Dental
identifications used.
• 2001. Sept. 11th. Dental ID’s used for victims of WTC,
Pentagon and Pennsylvania plane crashes

7. Scope and Purpose
• Management & maintenance of dental records that comply with
legal requirements.
• Identification of human remains by comparing anti mortem and post
mortem dental information.
• Collection and analysis of pattern marks (bite marks) on inanimate
materials or injured tissue.
• Recognition of the signs and symptoms of human abuse.
• Assessment of the age of the person.

8. Roles played by a forensic odontologist
• Dental Identification
• Multiple fatality incidence management
• Bitemark evidence collection and Analysis
• Abuse recognition
• Age estimation
• Expert testimony in criminal and civil litigation.

9. Individual Identification
• Traditional Methods
By visually analysing the body.
By checking for artifacts of identification like clothing, jewellery,
tattoos, eye colour etc.
When the person has suffered from a burn injury or if the body has
started decomposing, alernate methods has to be taken in order
to identify the individual.

10. Dental Identification
• Dental identification assumes a primary role in the identification of
remains when post mortem changes, traumatic tissue injury or lack
of a fingerprint record invalidate the use of visual or fingerprint
methods.
• The identification of dental remains is of primary importance when
the deceased person is skeletonized, decomposed, burned or
dismembered.
• The principal advantage of dental evidence is that, like other hard
tissues, it is often preserved after death.

11. • Reasons for identification:
Criminal ---Typically an investigation to a criminal death cannot
begin until the victim has been positively identified.
Marriage--- Individuals from many religious backgrounds cannot
remarry unless their partners are confirmed deceased.

12. – Monetary--- The payment of pensions, life assurance and other
benefits relies upon positive confirmation of death.
– Burial--- Many religions require that a positive identification be
made prior to burial in geographical sites.
– Social--- Society's duty to preserve human rights and dignity
beyond life begins with the basic premise of an identity.
– Closure--- The identification of individuals missing for
prolonged periods can bring sorrowful relief to family members.

13. Methods of identification using dental
records
1. Number of teeth
2. Restorations or prostheses
3. Dental caries
4. Malposition and malrotation
5. Peculiar shapes of teeth
6. Root canal therapy or other endodontic procedures
7. Bone patterns
8. Complete dentures
9. Relationship of the bite
10. Oral pathology
11. Occupational changes and socio-economic pattern of the dentition
12. Lip Prints
13. Sex and race determination

14. Radiography and crucial role in
identification
• 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.
• Sassouni has suggested use of measurements in postero-anterior and
lateral radiographs of the skull to match the ante and postmortem
radiographs, which includes
– Bigonial Width
– Cranial Height

15. Bimaxillary Width

16. – Bimaxillary breadth
– Height from bigonial width to temporal crest.
– Maximum cranial breadth
– Frontal sinus breadth
– Incisor height
– Facial height
• 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.

17. Max Frontal nasal width
Max Cranial Width Total Facial Height, Nasion to
Menton

18. • All intra and extra oral projections including panoramic radiographs
have to be taken as and when it is needed depending on the case and
type of remains.
 Intra oral radiographs
 Intraoral radiographs are difficult to perform particularly when
there is restricted mouth opening. It may be necessary to remove
soft tissues from the floor of the mouth or cheeks to insert the
film. A miniature intraoral X-ray source may be used.

19. Whenever fragmented remains consisting teeth,
restorations, bone pieces, appliances are recovered they
have to be separated by Johansan’s Method
– Place the debris on the plastic grid.
– Place the film on a wire grid identical to the plastic grid.
– From the resultant radiograph, type of remaining can be
identified.

20.  Extraoral Radiographs
o Radiographic techniques adapted for post mortem skulls
Postero anterior –to assess maxillofacial and frontal sinuses
Towne –to assess the condyle
Lateral technique –to assess facial bones sinuses and cranium
Panaromic technique –to assess adjacent structures related to
teeth
Lateral oblique projection –to assess mandible, body and
retromolar region.

21.  Individual identification by means of conventional bite-wing film
and subtraction radiography
– The digital subtraction technique used in clinical trials for the
evaluation of small tissue changes may, however, also be able to
determine hard tissue similarities for use in forensic dentistry.
– Principle of digital subtraction included features for correction of
variations in exposure geometry and density. Subtractions can be
performed between identical images (images of the same
individual) and between nonidentical images (images of two
different individuals).
– The manual comparison of bitewings may lead to matches
between radiographic data from missing and deceased persons.
These matches can, in cases that are not conclusive from a dental
point of view, be the basis for a combined investigation based on
dental status, fingerprints and/or DNA-analysis.
Individual identification by means of conventional bitewing film and subtraction radiography.
Forensic Science International 72 (1995) 55-64.

23.  Computed Tomography
o Conventional, two-dimensional or three-dimensional computed
tomography (CT) is a useful imaging method in the process of
human identification, and presents innumerable advantages as
compared with the traditional radiographic projection.
o Firstly, because this method is free from the problem of
structures superimposition beyond the plane of interest, and also
for allowing the visualization of small differences of density.
o An ante-mortem CT image provides information which can be
utilized in the construction of a post-mortem facsimile image,
considering that craniometric points can be precisely located and
measurements can be accurately performed.

24.  Dental Computed Tomography Screening Tool for Dental
Profiling
 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.

25. (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.

26. Multiple fatality incidence management
• A multiple fatality incident (MFI) develops when the number of
fatalities in the incident exceeds the number the medical examiner or
coroner’s facilities were designed to handle.
• The process of collection of dental information on victims in a mass
disaster is identical to the processes that are used in the
identification of a single fatality.

27. • With each MFI, there will be the need for personnel with different
levels of experience to work together to accomplish the common
goal of identifying all of the victims of the disaster.
• Personnel in all areas of the operation should have the ability and
desire to be detail oriented, as errors can lead to missed or
misidentifications.
• A mass disaster team should be organized and trained in
coordination with the local or state government to allow the most
expeditious deployment of a dental team when its services are
needed.

28. Bite mark evidence collection and analysis
• A bite mark is a patterned injury in skin or a pattern in an object
caused by the biting surfaces of human or animal teeth.
• The ABFO(AMERICAN BOARD OF FORENSIC ODONTOLOGY) manual
defines a bite mark as
(1) a physical alteration in a medium caused by the contact of teeth and
(2) a representative pattern left in an object or tissue by the dental
structures of an animal or human.

29. • The manual then describes a bite
mark as “a circular or oval
patterned injury consisting of two
opposing symmetrical, U-shaped
arches separated at their bases by
open spaces. Following the
periphery of the arches are a series
of individual abrasions,
contusions, and/or lacerations
reflecting the size, shape,
arrangement, and distribution of
the class characteristics of the
contacting surfaces of the human
dentition”.
• Bite marks can occur in a wide
variety of substrates, although the
most common of these is,
unfortunately, human skin.

30. • Teeth mark: This may occur when skin or other objects contact the
teeth instead of a biter intentionally closing his jaws, and hence his
teeth, into skin or an object. This is a valid distinction.
• A bite mark may be caused by a human biting another human, by an
animal biting a human, or by either biting an object.
• Teeth marks are passive, as they involve no active, intentional or
reflexive jaw movement, whereas in bite marks the jaw muscles are
active.

31. • Teeth mark examples include marks left by teeth on steering wheels,
dashboards, or other objects during motor vehicle accidents. If
struck in the mouth, the teeth of the victim may leave imprints on
the fist or other object.

32. Steps in Bite mark analysis
• If an investigator sees something on a victim that even resembles a
bite, the forensic dentist must be called in immediately, because bite
marks change significantly over time.
• The first step in analyzing the bite is to identify it as human. Animal
teeth are very different from humans' teeth, so they leave very
different bite-mark patterns.
• Next, the bite is swabbed for DNA, which may have been left in the
saliva of the biter. The dentist must also determine whether the bite
was self-inflicted.

33. • Measurements of each individual bite marks should be taken and
recorded. Also many photographs of the mark should be taken
because of the changing nature of the bites.
• Bruising can appear four hours after a bite and disappear after 36
hours.
• If the victim is deceased the dentist may have to wait until
the lividity stage, or pooling of the blood, clears and details are
visible. The bite photography must be conducted precisely, using
rulers and other scales to accurately depict the orientation, depth and
size of the bite. The photos are then magnified, enhanced and
corrected for distortions.
• Finally, bite marks on deceased victims are cut out from the skin in
the morgue and preserved in a compound called formalin, which
contains formaldehyde. Forensic dentists then make a silicone cast
of the bite mark.

34. • Terms which describes the types of bite marks:
– Abrasion - a scrape on the skin
– Artifact - when a piece of the body, such as an ear lobe, is
removed through biting
– Avulsion - a bite resulting in the removal of skin
– Contusion - a bruise
– Hemorrhage - a profusely bleeding bite
– Incision - a clean, neat wound
– Laceration - a puncture wound

35. Classification of Bite Marks
A. Cameron And SIMS Classification:
– This is based on the type of agent producing the bite mark and
material exhibiting it.
– 1. Agents:
• a) Human
• b) Animal
– 2. Materials:
• a) Skin, body tissue
• b) Food stuff
• c) Other materials

36. B. Mac Donald’s Classification:
• a) Tooth Pressure Marks: Marks produced on tissues as a result
of direct application of pressure by teeth. These are generally
produced by the incisal or occlusal surfaces of teeth.
• b) Tongue Pressure Marks: When sufficient amount of tissue is
taken into mouth, the tongue presses it against rigid areas.
• c) Tooth Scrape Marks: These are caused due to scraping of teeth
across the bitten material. They are usually caused by anterior
teeth and present as scratches or superficial abrasions.

37. C. According To Degree of Impression:
– Clearly Defined - significant pressure
– Obviously Defined - first degree pressure
– Quite Noticeable - violent pressure
– Lacerated - skin violently torn from body

38. Physical Charecteristics of a bite pattern:
• First it is important to determine which teeth made the marks. The
term ‘characteristic’, is a distinguishing feature, trait, or pattern
within the mark. It is of two types, class characteristic & individual
characteristic.
• Class characteristic is a feature, pattern, or trait which reflects a
given group and is not related to a particular individual. The biting
surfaces of teeth are related to their function like incising, tearing or
grinding. Front teeth are the primary biting teeth in bite marks.
• The two upper central incisors are wide, lateral incisors are narrower
and cuspids are cone shaped. The two lower centrals and two
laterals are uniform in width and lower cuspids are cone shaped. The
upper jaw is wider than the lower jaw.

39. Charecteristic of individual teeth:
1. Incisors: Rectangular shaped mark, sometimes with
perforations at the incisal angle areas
2. Canines: Triangular markings with apex towards labial and base
towards lingual
3. Premolars: Single or dual triangle with bases of triangles facing
each other or coming together as diamond shaped
4. Molars: Rarely leave bite marks, usually quadrilateral
markings.

40. Recording the Bite Mark- Documentation
• The appearance of a bite mark will change with time as swelling
subsides and tissue begins to repair itself.
• On the other hand, characteristics of the bite may become more
discernible as the inflammatory process diminishes. Therefore,
photographs to document the bite mark are critical and should be the
next step in evidence collection.
• Black and white as well as colour photographs should be taken, for
each has a specific role in the presentation of courtroom evidence.
Recognition of bite marks in child abuse cases. Pediatric Dentistry: September/October 1994 -
Volume 16, Number 5

41. •A millimeter ruler placed adjacent to the
bite mark will allow future comparison
with a suspect’s dentition. The plane of
the film should be parallel to the injured
surface and the millimeter ruler, to obtain
the best possible photographic results.
• In cases where the bite has occurred on
an extremely curved surface, it may be
necessary to take separate photographs of
each arch configuration. A female victim of sexual assault had an injury on
the skin of the posterior area from the left arm
confirmed in the initial forensic identification as a
human bite mark.

42. Recording the bite mark – Impression and Duplication
• The impression of bite mark surface is made with accurate and
stable dental impression materials commonly used for prosthodontic
treatments, rubber impression material – vinylpolysiloxane; supplied
in two consistencies: low viscosity (light body) and putty.
• The physical properties of these dental materials have been shown
suitable for use to duplicate the contours and surface characteristics
of the skin. In addition, silicones have the best recovery from
deformation during removal of the impression.
• Impression materials are used to make an accurate replica of the
tooth mark. The impression gives a negative reproduction of the
tooth mark, and by filling it with dental stone or other material, such
as epoxy resin, a positive cast is made for study of tooth and the
profile of the mark.

43. • The accuracy, detail, and quality of this final replica are of greatest
importance for the results. Between the various types of impression
materials currently available and the qualities they possess, the elastic
impression rubber materials may be the choice.
• Alternatively, silicones may be the preference because of their physical and
mechanical properties, such as lowest dimensional change on setting,
lowest permanent deformation and highest detail reproduction.
Evidence Collection of a Tooth Mark in a Crime Scene: Importance of the Dental Materials in
Forensic Dentistry. Revista Portuguesa de Estomatologia, Medicina Dentária e Cirurgia
Maxilofacial. Volume 50, No3, 2009.

44. Newer methods of analysing bite marks
• Using comparison overlays with DentalPrint:
- Comparison overlays are obtained in three steps:
- First, the teeth involved in the bite mark are identified.
- Second, a contact plane is created from the three highest points
detected in areas defined in the 3D images of the dental casts.
- Finally, biting edges are obtained with DentalPrint, which allows the
contact plane to extend deep into the teeth.
- The perimeter of the suspect’s biting edges can be printed on
transparent acetate film or converted into a bmp file.
Effectiveness of Comparison Overlays Generated with DentalPrint Software in Bite Mark
Analysis
J Forensic Sci, January 2007, Vol. 52, No. 1

46. • 3D/CAD supported photogrammetry approach:
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.
Bite mark documentation and analysis: the forensic 3D/CAD supported photogrammetry approach
Forensic Science International 135 (2003) 115–121

47. Data transformation of the photogrammetric bite mark
documentation in the RolleiMetric software system.

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

49. 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

50. • 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 surfa 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

51. 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

52. Identification by DNA
• DNA fingerprinting or DNA profile are encrypted sets of numbers
that reflect a persons DNA makeup, which can also be used as the
persons identifier.
• Gene is a segment of DNA that codes for a particular protein. This
accounts for only 2-5% of entire cellular DNA. The function of the
remaining 95% or more of the DNA is not known and is called as
non-coding DNA or junk DNA.
• ANATOMICAL LOCATIONS FOR DNA IN TOOTH:
– The dentin on the crown of the tooth is covered by enamel. The
enamel has an ectodermic origin and is an extremely mineralized
tissue. Furthermore, it is an acellular and avascular structure
without nerves. The root dentin is covered by the cement,
another type of calcified connective tissue.

53. • Soft tissue within coronal and radicular pulp chamber consists of
odontoblasts, fibroblasts, endothelial cells, peripheral nerve,
undifferentiated mesenchymal cells and nucleated components of
blood which are rich sources of DNA.
• Other less frequently used anatomical locations of DNA includes,
odontoblastic process that extend into dentinal tubules, soft tissue
within accessory canals, cellular cementum, adherent bone and
periodontal ligament fibres.

54. Abuse Recognition
• Identifying and reporting
abuse is a complex and
emotional area. Healthcare
practitioners are required by law in most juristrictions to report
suspected cases of abuse.
• The head and neck area is a common target in abuse.
• Extraoral injuries consistent in shape and appearance to a hand
or object are identifiable.

55. • Intraoral trauma can occur as the result of strikes to the face, causing
torn frena and fractured, mobile, or avulsed teeth.
• Abuse or assault victims may or may not be hospitalized with
serious injuries. Surviving victims may not be seen by an
odontologist immediately. Several hours or sometimes even days
may pass before the forensic odontologist is called. Occasionally
emergency room personnel take photographs of the patterned
injuries during early treatment.
• Deciding to report suspected abuse requires sound judgment,
especially considering that the parent or guardian may be the
perpetrator. If a report is initiated, the ensuing investigation will be
difficult for all concerned.

56. Age estimation
• Researchers have studied the processes of human aging by
many different methods. These include developmental,
histological, biochemical, and anthropological techniques.

57. Methods of Age Estimation
• Literature describes several techniques that address age
estimation in adults. The various methods are divided into
three categories:
1. Morphological methods
2. Biochemical methods
3. Radiological methods.

58. Morphological methods
Morphological methods are based on assessment of teeth (ex-vivo).
Hence, these methods require extracted teeth for microscopic
preparation. However, these methods may not be acceptable due to
ethical, religious, cultural, or scientific reasons.
• Gustafson’s Method (1950)
Gustafson (1950) and Thoma (1944) described the age changes
occurring in the dental tissues and noted six changes related to age.
They are:
a. Attrition of the incisal or occlusal surfaces due to mastication (A)
b. Periodontitis (P)
c. Secondary dentin (S)
d. Cementum apposition (C)
e. Root resorption (R)
f. Transparency of the root (T)

59. • Gustafson suggested the last two changes. In the method proposed,
each sign was ranked and allotted 0, 1, 2, 3 points. The point values
of each age-change are added according to the following formula:
• An+ Pn + Sn + Cn + Rn + Tn = points.
• The error of estimation as calculated by Gustafson (1950) was ±3.6
years.
• Disadvantage: Cannot be used in living person.

60. • Dalitz Method (1962)
• Dalitz re-examined Gustafson’s method and suggested a 5-point
system from 0-4, instead of the 4-point system that was previously
used.
• This change was proposed in order to give a slightly greater
accuracy. The results showed that root resorption and secondary
cementum formation could be disregarded. The other criteria,
attrition (A), periodontitis (P), secondary dentine (S) deposition, and
transparency of the root (T) of the 12 anterior teeth, are related
appreciably to age and to a similar degree.
• Disadvantage: It does not take into account bicuspids and molar
teeth.

61. • Other morphological methods were, Bang and Ramm method
(1970), Johanson method (1971), Maple’s method (1978), Solheim
method (1993). All these methods considered in varying degrees the
six factors given by Gustafson in order to make the procedure
simple and in varying levels of accuracy.
Biochemical methods:
• The biochemical methods are based on the racemization of amino
acids. The racemization of amino acids is a reversible first-order
reaction and is relatively rapid in living tissues in which metabolism
are slow.
• Aspartic acid has been reported to have the highest racemization rate
of all amino acids and to be stored during aging. In particular, L-
aspartic acids are converted to D-aspartic acids and thus the levels of
D-aspartic acid in human enamel, dentine, and cementum increase
with age.

62. • Some methods are Helfman and Bada method (1975,1976) and Ritz
et al method (1995).
Radiographic Methods
• The radiological age determination is based on assessment of
various features as follows:
– Jaw bones prenatally
– Appearance of tooth germs
– Earliest detectable trace of mineralization or beginning of
mineralization
– Early mineralization in various deciduous teeth during
intrauterine life
– Degree of crown completion

63. – Eruption of the crown into the oral cavity
– Degree of root completion of erupted or unerupted teeth.
– Degree of resorption of deciduous teeth
– Measurement of open apices in teeth
– Volume of pulp chamber and root canals/formation of
physiological secondary dentine
– Tooth-to-pulp ratio
– Third molar development and topography

64. Age estimation in children
• Dental age estimation in children and adolescents is based on the
time of emergence of the tooth in the oral cavity and the tooth
calcification.
• The radiographic analysis of developing dentition, especially when
there is no clinical evidence available (2.5-6 years) as well as the
clinical tooth emergence in various phases will help in age
determination.
• Age estimation in children was also done using analysis of open
apices of root. The seven left permanent mandibular teeth were
valued. The number of teeth with root development completed with
apical ends completely closed was calculated .

65. Age estimation in adults
• The two methods commonly followed are the assessment of the
volume of teeth and the development of the third molar.
– 1. Volume assessment of teeth
a. Pulp-to-tooth ratio method by Kvaal
b. Coronal pulp cavity index
– 2. Development of third molar
a. Harris and Nortje method
b. Van Heerden system

66. • Volume assessment of teeth: The age estimation in adults can be
achieved by radiological determination of the reduction in size of
the pulp cavity resulting from a secondary dentine deposition, which
is proportional to the age of the individual.
• Development of third molar: The radiographic age estimation
becomes problematic after 17 years of age as eruption of permanent
dentition completes by that age with the eruption of the third molar.
Later, the development of the third molar may be taken as a guide to
determine the age of the individual

67. Demirjian, Goldstein and Tanner method (1973)
• In 1973, Demirjian introduced a method which estimated
chronological age based on developments of seven teeth from the
left side of the mandible. This method was similar to that of Tanner,
Whitehouse, and Healy, who estimated chronological age based on
the maturity of hands and wrists.

68. Expert Testimony in Criminal and Civil
Litigation
• Forensic odontologists are frequently called to give sworn testimony
in depositions and courtrooms. The testimony may involve the
previously mentioned areas of dental identification, bitemark
analysis, or age estimation. Dentists participating in forensic
casework should expect that at some point they will be required to
provide sworn testimony.

69. • Forensic dentists also may be called to provide an opinion in
standard of care, personal injury, dental fraud, or other civil cases.
These cases, as with other forensic cases, require the evaluation of
material and the development of an opinion concerning the case.

70. How a prosthodontist contributes to the
field of forensic odontology?
• The role of prosthodontics in forensic odontology:
– Sound knowledge of dental materials
– New ways of engraving records into prosthesis
– Study of rugae patterns—rugoscopy
– Impression making and models of bite marks
– Lip print recording and identification.

71. Engraving records in Prosthesis
• Labeled dentures can be important in identifying the owners in case
of an accident, loss of memory, state of unconsciousness, being
inadvently misplaced, or in identifying the bodies of those who have
died in the calamity.
• They are of two types:
– Surface methods
– Inclusion methods

72. Surface methods
• Writing, scribing on tissue fitting surface or the polished surface
with fibre-tipped pen, embossing initials of the patient in master cast
with burs. It is not the permanent method. Engraving records on
surface can cause food debris accumulation and infections.

73. Inclusion Methods
• ID band:
– Dentures may be marked with stainless steel band. The most
commonly used fire-resistant materials are titanium foil and HO
matrix band containing an identifiable coding system reprinting
patient details.
• Laser etching:
– Copper vapor laser can etch patient identification in metal
surface of partial dentures. The method is very expensive and
needs special equipment and expertise.

74. • T Bar: A T-shaped clear PMMA resin bar is constructed by cutting
baseplate wax and then is flasked, packed, processed and finished in
clear or pink PMMA. An identification printed label against the flat
surface of the bar is fixed. It is then surface-polished to produce a
clear window displaying the ID label.
• Electronic Microchips: Patient information was etched onto a chip
measuring 5 × 5 × 0.6 mm. It is bonded with acrylic resin. Further
advancement includes specialized equipment to transfer details to
computer.
– Its disadvantage is that it can be inscribed only by manufacturer
and not by the dentist.

75. • Lenticular System: Lenticular lens is used to produce images with
an illusion of depth, morph or the ability to change or move as the
image is viewed from different angles. Information once written
cannot be changed, may not withstand fire.
• RFID Tags: A radiofrequency identification tag is a cosmetic,
effective labelling method permitting rapid and reliable
identification by the wearer size—8.5 × 2.2 mm. Large amount of
denture usage data can be stored in them.

76. • Photographs: Patient photograph is embedded to clear acrylic
denture base. Useful in countries having low literacy rate. It was
resistant only upto 200 to 300°C.
• Bar Codes: Similar to bar coding of various other consumer goods.
The bar code that is resistant to high temperatures is incorporated
into a denture and sealed with heat cure acrylic resin.

77. Chelioscopy:
• The external surface of lips has many elevations and depressions
forming a characteristic pattern called lip prints, examination of
which is known as chelioscopy.
• In 1932, Edmond Locard, one of France criminologists
recommended the use of lip prints in personal identification and
criminalization.
• Snyder reported in his book homicide investigation that the
characteristics of the lips formed by lip grooves are as individually
distinctive as the ridge characteristics of finger prints

78. Renaud Lip Print Classification
A. Complete vertical
B. Incomplete vertical
C. Complete bifurcated
D. Incomplete bifurcated
E. Complete branched
F. Incomplete branched
G. Reticular pattern
H. X or coma form
I. Horizontal
J. Horizontal with other forms bifurcate,
branch

79. • The methods to obtain lip prints are of two types:
• Direct method : Both lips after cleaning with wet cotton gauze, a
thin layer of lipstick is applied with a brush. The lipstick is
allowed to dry for about two minutes, and then a lip impression
is made on a strip of cellophane tape on the glued portion, which
is transferred to the registration sheet.

80. • Indirect method : For the indirect impression, the lipstick is applied
onto the lips and lip prints is recorded directly onto a glass slide by
moving the glass slide from one corner to the other corner of the lip.
This print on the glass slide simulates any trace found at a crime
site. This impression is then lifted onto the glued surface of the
cellophane tape and transferred to the column of the registration
sheet by the observer.

81. Rugoscopy:
• It is the study of palatal rugae.
• Palatal rugae are unique to and individual and are protected from
trauma by their natural position in the head and insulated from heat
by tongue and buccal fat pads, unlike fingerprints which can get
destroyed.
• With age, rugae change length but remain in the same position
throughout the entire life of a person.
• Rugoscopy may not be so useful in crime scene investigation but
very useful in necroidentification technique, especially in
aeronautical accidents.

82. Summarizing
• Dental experts must be advocates for the truth and endeavor to find
that truth by the application of their special knowledge and skills.
The unwavering goal of the forensic dental expert must be
impartiality, thoroughness, and accuracy.
• Forensic dentistry is a multifaceted, interesting, and rewarding blend
of dentistry and the law. 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.

83. • Their opinions may influence judges and juries in cases that
can and have involved exoneration, the loss of liberty, and
even the loss of life. This is an awesome and sobering
responsibility that should not be casually undertaken. “The
majority of those who fail and come to grief do so through
neglecting the apparently insignificant details.”

84. References
• Forensic Dentistry ,2nd Edition, CRC Press, UK
• 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.
• Individual identification by means of conventional bitewing film
and subtraction radiography. Forensic Science International 72
(1995) 55-64.
• Role of Prosthodontist in Forensic Odontology, IJCDS, November,
2011;2(4), 85-89.
• Fundamentals of Stereolithography, an Useful Tool for Diagnosis in
Dentistry, Int. J. Dent. Sc.,17(1),15-21.
• Dental Age Estimation Methods: A Review, International Journal of
Advanced Health Sciences;1(12):19-25.

85. • 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.
• Contribution of a Prosthodontist in the Field of Forensic
Odontology, International Journal of Prosthodontics and Restorative
Dentistry, April-June 2014;4(2):56-59
• Computed Tomography Use on Age Estimation in Forensic
Dentistry: A Review, Journal of Forensic Science &
Criminology,2016;4(1):1-6.
• Use of images for human identification in forensic dentistry. Radiol
Bras. 2009;42(2):125–130.
• Dental CT Imaging as a Screening Tool for Dental Profiling:
Advantages and Limitations, Forensic Sci,2006;51(1):113-119.

86. • Effectiveness of Comparison Overlays Generated with DentalPrintr
Software in Bite Mark Analysis, J Forensic Sci, 2007;52(1):151-
156.
• 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.
• Identification of a person with the help of bite mark analysis, journal
of oral biology and cranio facial research,2003;3:88-9 1.
• An Overview of Bite mark Analysis, J Indian Acad Forensic Med,
2012;34(1):61-66.
• Dental DNA fingerprinting in identification of Human Remains.
2010;2(2):63-68.