forensic odontology

1. Forensic odontology
Dr.Shubham Patel
MDS (oral pathology)

2. INTRODUCTION
• The term “forensic” is from the Latin, meaning forum
or a place where legal matters are discussed.
• The science of dentistry as related to the law is known
as forensic dentistry or forensic odontology.
• The theory behind forensic dentistry is that “no two
mouths are alike.”

3. • Forensic dentistry plays an important role in mass disasters,
child/elder/spouse abuse cases, bite mark analysis, criminal
and natural deaths and injuries, bioterrorism, etc.,
• It also helps in identification of decomposed and charred
bodies like that of drowned persons, burns and victims of
motor vehicle accidents.
• The different methods employed in forensic dentistry include
bite mark analysis, tooth prints, rugoscopy, cheiloscopy,
dental-DNA analysis, radiographs, and photographic analysis.

4. • Forensic odontology can be defined as a specialised
branch in dentistry which in the interest of justice
deals with the proper handling, examination of dental
evidence with proper presentation and proper
evaluation of dental findings- FDI

5. • “what a nightmare !.... Bodies as of Negroes –
blackened, heads carbonised, shrunk & reduced to
nothing, but only the teeth remained”
-Dr Oscar Amoedo “ Father of forensic odontology”

6. SCOPE AND PURPOSE
• Identifying unknown human remains through comparison of
postmortem dental evidence with dental records of the
presumed deceased.
• Age estimation of both the living and deceased.
• Recognition and analysis of bitemarks found on victims .
• Determining the gender of an unidentified person /
individual.
• Identification of victims in mass disasters.
• Presenting evidence in court as expert witness.

7. Parameters to be compared
• Teeth
• Prosthetic appliance – briges , partial denture , crown
, complete denture .
• Restorations
• Shape , form (morphological) pecularities.
• Genetic anomalies.

8. PALATAL RUGAE IN IDENTIFICATION
• A useful method of identifying edentate individuals is by
examining the palatal rugae pattern. The rugae pattern on
the deceased’s maxilla or maxillary denture may be
compared to old dentures that may be recovered from the
decedent’s residence, or plaster models that may be
available with the treating dentist.
• Rugae pattern, like teeth, are considered unique to an
individual. They seldom change shape with age and
reappear after trauma or surgical procedures.

9. Classification of Palatal Rugae
Lysell-
•Three types:
O Primary rugae (>5 mm)
O Secondary rugae (3–5 mm)
O Fragmentary rugae (2< 2 mm is not taken into
consideration).
Thomas and Kotze-
branched, unified, cross-linked, annular, and papillary.
Kapali and associates
according to shape as straight, curved, wavy, and circular

10. Bite Marks
• Bite marks have been defined by MacDonald as “a mark
caused by the teeth either alone or in combination with
other mouth parts”.
• Bite marks may be caused by humans or animals; they may
be on tissue, food items or on objects.
• Biting is considered to be a primitive type of assault and
results when teeth are employed as a weapon in an act of
dominance or desperation

11. • Classification of Bite Marks
Cameron and Sims’ Classification.
Based on the type of agent producing the bite mark and the material
exhibiting it.
AGENTS
O Human
O Animal.
Materials
O Skin, body tissue
O Foodstuff
O Other materials.

12. • MacDonald’s Classification
Eiologic classification.
Tooth pressure marks. Marks produced on tissue as a result of ‘direct
application of pressure by teeth’. These are generally produced by the
incisal or occlusal surfaces of teeth.
Tongue pressure marks. When sufficient amount of tissue is taken into
the mouth, the tongue presses it against rigid areas such as the lingual
surface of teeth and palatal rugae. The marks thus left on the skin are
referred to as ‘suckling,’ since there is a combination of sucking and
tongue thrusting involved.
Tooth scrape marks. These are marks caused due to scraping of teeth
across the bitten material. They are usually caused by anterior teeth
and present as scratches or superficial abrasions.

13. Bite Mark Appearance
• Type of Injury- contusions or bruises are the most common
presentation of bite marks.
• Depending on the skin color they appear as reddish or
purplish or dark brown discoloration on the skin surface and
are due to the blood escaping into subcutaneous tissue from
ruptured minute vessels.
• When the intensity of the bite is great, there may be a break
in the integrity of skin surface, resulting in lacerations.
• The most extreme form of bite mark injury is avulsion, where
part of the tissue is bitten off.

14. • Identifying the Injury as a Bite Mark-
Gross charateristics. A circular or elliptical mark
Class charateristics. The marks produced by different classes
of teeth are usually distinct, allowing one to differentiate the
type of tooth within a bite mark.
Individual charateristics. Class charateristics may, in turn, have
features such as fractures, rotations, spacing, etc. Such
attributes are referred to as individual features and make the
bite mark distinct.
Site of Bite Marks. Bite marks may be found on any part of the
body. However, Pretty and Sweet state that females are most
often bitten on the breasts and legs (especially on the inner
part of thigh)—a result of sexual assault. Male children are
prone to be bitten on the genitals, a result of child sexual abuse

15. •Conclusions in Bite Mark Analysis-
Definite Biter. There is reasonable medical certainty to
indicate that the bite mark has been produced by the
suspect’s dentition: there is concordance of sufficient
distinctive, individual characteristics to confer
uniqueness within the population under consideration.
Probable Biter. Bite mark shows some degree of
specificity to the suspect’s teeth by virtue of a sufficient
number of matching points, including some
corresponding individual characteristics. There is
absence of any unexplainable discrepancies.

16. • Possible Biter. The bite mark and the suspect’s dentition are
consistent: although the suspect’s teeth could have made the bite
mark, there are no characteristic matches to be absolutely certain.
The similarity is non-specific or there is similarity of class
characteristics.
• Not the Biter. The bite mark and the suspect’s dentition are not
consistent: features on the bite mark indicate that the suspect’s teeth
have definitely not caused them.

17. Lip Prints
• The wrinkles and grooves visible on the lips have been
named by Tsuchihashi as ‘sulci labiorum rubrorum’.
• The imprint produced by these grooves is termed ‘lip
print’, the examination of which is referred to as
‘cheiloscopy’.
• These grooves are heritable and are supposed to be
individualistic.

18. • Lip prints were first classified by Santos into two categories:
• Simple wrinkles
O Straight line
O Curved line
O Angled line
O Sine-shaped curve.

19. • Compound wrinkles
O Bifurcated
O Trifurcated
O Anomalous.
Tsuchihashi later proposed a separate classification, dividing the
pattern of grooves into six types
Type I – Clear-cut vertical grooves that run across the entire lip
Type I’ – Similar to type I, but do not cover the entire lip
Type II – Branched grooves
Type III – Intersected grooves
Type IV – Reticular grooves
Type V – Grooves that cannot be morphologically differentiated.

20. DENTAL AGE ESTIMATION
• While different physiologic systems are used to estimate age, teeth
are considered better suited than bones.
• Dental age is one of the few measures of physiologic development
that is uniformly applicable from infancy to late adolescence.
• After attaining maturity, teeth continue to undergo changes, making
age estimation possible in adults.

21. • Dental Age Estimation Methods-
Dental age estimation makes use of morphologic, radiographic,
histological, and biochemical methods to examine agedependant
changes in teeth.
Age estimation using the dentition may be grouped into three phases:
O Prenatal, neonatal and early postnatal period
O Children and adolescents
O Adults.

22. • Literature describes several techniques that address age estimation in
adults.
• The various methods are divided into three categories:
• 1. Morphological methods- Gustafson (1950), Dalitz (1962), Bang and
Ramm (1970), Johanson (1971), Maples (1978), Solheim (1993) are
few morphological methods
• 2. Biochemical methods- 1. Helfman and Bada method (1975, 1976)
2. Ritz et al. method (1995)4
• 3. Radiological methods.-

23. 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
• 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

24. • 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)
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 exact equation calculated was: y = 11.43 + 4.56x, where, y = age and x = points
according to the formula above. The error of estimation as calculated by Gustafson
(1950) was ±3.6 years.
Disadvantage: Cannot be used in living person.

25. Value of Third Molars in Age Estimation
• Although the third molar is a valuable indicator of age in the 16–22
year-old age-group where all other teeth have completely developed,
its accuracy in age estimation is questionable due to great variation in
its genesis, position, morphology, and time of formation.
• However, Gunst and associates underscore its importance,
particularly due to the relative inaccuracy of skeletal predictors of age
in this age-group. In particular, the development of the third molar is
important for determining whether an individual is a juvenile (<18) or
adult (>18)