Transcript FORENSIC ODONTOLOGY

FORENSIC ODONTOLOGY
• FORENSIC IS DERIVED FROM THE LATIN
WORD FORUM WHICH MEANS COURT OF
LAW
• ODONTOLOGYSTUDY OF TEETH
• DEFINED AS THAT BRANCH OF DENTISTRY
WHICH ,IN THE INTEREST OF JUSTICE
,DEALS WITH THE PROPER HANDLING AND
EXAMINATION OF DENTAL EVIDENCE,AND
WITH THE PROPER EVALUATION AND
PRESENTATION OF DENTAL FINDINGS
• FORENSIC DENTISTRY PLAYS A
MAJOR ROLE IN IDENTIFICATION IN
MAN MADE OR NATURAL DISASTER –
EVENTS THAT RESULT IN MULTIPLE
FATALITIES THAT MAY NOT BE
IDENTIFIABLE THROUGH
CONVENTIONAL METHODS SUCH AS
FINGER PRINTS
• THE EARLIEST KNOWN EXAMPLE BY DENTAL
MEANS DATES BACK TO 66 AD
• ELABORATE DENTAL RECORDS INCLUDING
RADIOGRAPHS AND SPARE CROWNS IDENTIFIED
THE BODY OF ADOLPH HITLER ,THE MOST HIGH
PROFILE CASE OF DENTAL IDENTIFICATION
• IT RELIES ON SOUND KNOWLEDGE OF TEETH AND
JAWS ,POSSESED BY DENTIST AND
INCORPORATES DENTAL ANATOMY ,HISTOLOGY
RADIOGRAPHY ,DENTAL MATERIALS AND
DEVELOPMENTAL ANOMALIES
FORENSIC ODONTOLOGY DELVE INTO
•
IDENTIFYING UNKNOWN HUMAN REMAINS THROUGH
DENTAL RECORDS ,AND ASSISTING AT LOCATION OF MASS
DISASTER
•
ELICITING THE ETHNICITY AND ASSISTING IN BUILDING UP
A PICTURE OF LIFESTYLE AND DIET OF SKELETAL REMAINS
AT ARCHEOLOGICAL SITES
•
DETERMINIG THE GENDER OF AN UNIDENTIFIED
INDIVIDUAL
•
AGE ESTIMATION OF BOTH THE LIVING AND DECEASED
•
RECOGNITION AND ANALYSIS OF BITE MARKS FOUND ON
VICTIMS OF ATTACK AND OTHER SUBSTANCES SUCH AS
FOOD STUFF
6.
PRESENTING EVIDENCE IN COURT AS AN EXPERT
WITNESS
PERSONAL IDENTIFICATION
• IDENTIFICATION IS THE ESTABLISHMENT OF
A PERSONS INDIVIDUALITY
• REQUIRED FOR LEGAL AND HUMANITARIAN
REASONS
• HELP IN SETTLEMENT OF PROPERTY
,FACLITATE REMARRIAGE OF A SURVIVING
SPOUSE AND ALLOW CREMATION OR
BURIAL OF THE BODY ,ACCORDING TO
RELAVENT RELIGIOUS AND CULTURAL
CUSTOMS
TRADITIONAL METHODS
• VISUALLY RECOGNISING BODY
• PERSONAL PROPERTY SUCH AS
CLOTHING ,JEWELLERY ETC
VISUALLY IDENTIFYING THAT IS BURNT OR
DECOMPODSED CAN BE AVERY
TRAUMATIC EXPERIENCE FOR RELATIVES
AND FRIENDS ,THE BETTER OPTION
IDENTIFICATION IS FORENSIC EXPERT TO
ANALYSE PHYSICAL FEATURES PRESENT
IN THE BODY
• PHYSICAL FEATURES ARE PRONE TO
CHANGE OVER TIME ,FINGER PRINTS
ARE EXCEPTIONS BUT LIKE OTHER
SOFT TISSUE,UNDERGO POST
MORTUM CHANGE
• BEING THE STRONGEST STRUCTURE
PRESENT IN THE BODY DENTAL HARD
TISSUES ARE RESISTANT TO POST
MORTUM DECOMPOSITION
• MOREOVER MOST MATERIAL USED BY
DENTIST FOR RESTORING TEETH ARE ALSO
RESISTANT TO POST MORTUM
DESTRUCTION
• THEREFORE THE USE OF DENTAL
EVIDENCE IS THE METHOD OF CHOICE IN
ESTABLISHING THE IDENTITY OF BADLY
BURNT ,TRAUMATISED,DECOMPOSED AND
SKELETONISED REMAINS
BASIS FOR DENTAL
IDENTIFICATION
• HUMAN DENTITION IS NEVER SAME IN
ANY TWO INDIVIDUALS
• THE ,MORPHLOGY AND
ARRANGEMENT OF TEETH VARY
FROM PERSON TO PERSON
• TEETH ARE RELATIVELY
RESISTANTNTO ENVIRONMENTAL
INSULTS AFTER DEATH
DENTAL IDENTIFICATION
PROCEDURES
• TWO FORMS:
1. COMPARITIVE IDENTIFICATION:COMPARING
THE DEAD INDIVIDUALS TEETH WITH
PRESUMED DENTAL RECORDS OF THE
INDIVIDUAL
2. RECONSTRUCTIVE IDENTIFICATION
(DENTAL PROFILING):ATTEMPTS TO ELICIT
THE ETHNICITY OR “RACE” ,GENDER , AGE
AND OCCUPATION OF THE DEAD
INDIVIDUAL.UNDERTAKEN WHEN VIRTUALLY
NO CLUE EXISTS
COMPARITIVE DENTAL
IDENTIFICATION
• INCLUDES FOUR STEPS
STEP 1:ORAL AUTOPSY
STEP 2:OBTAINING DENTAL RECORDS
STEP 3:COMPARING POST MORTUM
AND ANTIMORTUM DENTAL DATA
STEP 4:WRITTIN A REPORT AND
DRAWING CONCLUSION
ORAL AUTOPSY
• ALSO KNOWN AS NECROPSY OR POST MORTUM
• IT HAS A SYSTEMATIC PROTOCOL STARTING WITH
CRITICAL EXAMINATION OF THE EXTERNAL
FEATURES OF THE BODY SUCH AS GENDER,
ETHNICITY ,BUILT, WOUNDS.SCARS ,TATTOOS AND
BODY PIERCING.
• PHOTOGRAPHS,
RADIOGRAPHS,FINGERPRINTS,FINGER NAIL
SCRAPING AND HAIR SAMPLE MAY BE OBTAINED
ACCORDING TO THE REQUIREMENTS
• ORAL EXAMINATION IS AN ESSENTIAL PART
OF POSTMORTUM PROCEDURS
• A FORENSIC DENTIST WHO CONDUCT ORAL
AUTOPSY SHOULD HAVE ADEQUATE
KNOWLEDGE ABOUT COMMON
POSTMORTUM FINDINGS SUCH AS RIGOR
MORTIS ,LIVER MORTIS ,DECOMPOSITION
AND POSTMOTUM ARTEFACTS
• RIGOR MORTIS MAY RENDER THE JAW AND
THE USE OF MOUTH GAGS OR INTRA ORAL
MYOTOMY IS ESSENTIAL FOR JAW
SEPERATION
• Since teeth may be brittle in burned cases, they
need to be reinforced with cyanoacrylate
cements, polyvinyl acetate or clear acrylic spray
prior to examination
• Access for radiology in incinerated bodies can
be obtained by removing tongue and contents of
floor of mouth in a ‘tunneling’ fashion from
beneath the skin
• The status of each tooth whether intact carious
restored or missing should be carefully noted
• A thorough examination of soft tissue injuries,
fracture and presence of foreign bodies is under
taken and samples of hard and soft tissues may
be obtained for further investigation
• All information pertaining to the body must be
entered on to standard ‘interpol post-mortem
form’, which is color-coded in pink
OBTAINING DENTAL RECORDS
• FROM TREATING
DENTIST,SPEACILIST,HOSPITAL RECORDS
IN THE FORM OF DENTAL CHARTS
RADIOGRAPHS,CASTS, AND/OR
PHOTOGRAPHS
• CONTENT OF ALL AVAILABLE RECORDS
SHOULD BE TRANSCRIBED ON TO THE
STANDARD ‘INTERPOL ANTEMRTEM FORM’
WHICH IS COLOUR CODED IN YELLOW
COMPARNG POST-MORTEM &ANTE-MORTEM
DENTAL RECORDS
• FEATURES COMPARED INCLUDE TOOTH
MORPHOLOGY AND ASSOSIATED BONY
STRUCTURES, PATHOLOGY AND
RESTORATIONS
• AN INDIVIDUAL WITH MULTIPLE DENTAL
TREATMENT AND UNUSUAL FEATURES HAS
A BETTER LIKELIHOOD OF BEING
IDENTIFIED THAN SOMEONE WITH NO
EXTRAORDINARY DENTAL
CHARECTERISTICS
• COMPARISON SHOULD TAKE IN TO
ACCOUNT QUALITY RATHER THAN
QUANTITY
WRITING A REPORT AND DRAWING
CONCLUSION
• CONFIRMS IDENTIFICATION:MATCH EACH
OTHER
• PROBABLE IDENTIFICATION:HIGH LEVEL OF
CONCORDANCE BETWEEN THE TWO SETS OF
DATA BUT,USUALLY ,WITH NO RADIOGRAPHIC
SUPPORT
• POSSIBLE IDENTIFICATION:EXPLAINABLE
IDENTIFICATION BETWEEN THE ANTE AND
POST-MORTEM DATA
• INSUFFICIANT INFORMATION:AVAILABLE
ANTI&POS-MORTEM DATA ARE INSUFFFICIANT
• EXCLUDES IDENTIFICATION:ANTI&POST
MORTEM DATA ARE CLEARLY INCONSISTENT
IDENTIFICATION IN DISASTERS
• INVOLVES COMPARING HUNDREDS OR
THOUSANDS ,OF ANTE &POST MORTEM
DATA
• HUMAINS REMAINS IN SUCH EVENTS MAY
BE HIGHLY FRAGMENTED , ONLY PART OF
BODY MAY BE RECOVERED ;THE NODIES
MAY BE INCINERATED OR COMMINGLED i.e.
PARTS OF TWO BODIES MAY BE MIXED
DENTAL SECTION
• FORENSIC DENTIST ARE USUALLY
PART OF A TEAM OF IDENTIFICATION
SPECIALIST
• THREE SUB SECTIONS
1.POST MORTEM UNITS
2.ANTE –MORTEM UNITS
3.DENTAL COMPARISON IDENTIFICATION UNITS
POST-MOTEM UNIT
• THE LOCATION AT WHICH A BODY IS
RECOVERED NOTED AND PRELIMINARY
EXAMINATION OF MOUTH IS MADE TO
EVALUATE THE ORAL CONDITION
• DEFINITIVE EXAMINATION AT MORTURY OF
POST-MORTUM UNIT
• A PORTABLE DENTAL RDIGRAPHY SHOULD
BE INSTALLED, TAKING PRECAUTIONS
AGAINST RADIATION HAZARDS
• RESPONSIBLE FOR PROCESSING
RADIOGRAPHS &MAY ALSO NEED ARRANGE
FOR PHOTOGRAPHY OF TEETH
• TEETH AND JAW SPECIMEN MAY BE
REMOVED FROM A BODY FOR THE
CONVEININCE OF EXAMINATION
ANTE-MORTEM UNIT
• MOST DIFFICULT.
• THE MEMBERS NEED TO COLLECT AS
MUCH AS INFORMATION AS POSSIBLE IN
THE SHORTEST PERIOD OF TIME
• BEGINS WITH LOCATING THE DENTAL
RECORDS OF THE VICTIMS
COMMUNICATING WITH POLICE, DENTIST,
AND RELATIVES OF THE VICTIMS
• ALL INFORMATION OBTAINED MUST BE
TRANSFERRED ONTO THE STANDARD
INTERPOL ANTE-MORTEM FORM
• THIS CONSTITUTE THE ANTE MORTEM
COMPOSITE CHART
DENTAL COMPARISON AND
IDENTIFICATION UNIT
• COMPARISON AND CONFORMATION OF
IDENTIFICATION
• THE ANTE-MORTEM DATA ARE TAKEN
INDIVIDUALLY AND COMPARED TO THE
POST-MORTEM DATA THAT ARE SPREAD
OUT (COMPUTER SOFTWARE
DEVELOPED TO SIMPLIFY COMPARISON )
• FINAL IDENTIFICATION SHOULD ALWAYS
BE DONE BY DENTIST MANUALLY
IDENTIFICATION FROM DENTAL
DNA
• TEETH ARE EXCELLENT OURCE OF DNA
SINCE IT CAN RESIST EXTREME CONDITION
• PCR ALLOWS AMPLIFICATION OF EVEN
HIGHL DEGRADED DNA
• MAJOR ADVANTAGE IS THAT IF
DECENDENT’S ANTE MOTEM SAMPLE (HAIR
FROM HAIR BRUSH, EPITHELIAL CELLS
FROM TOOTH BRUSH OR BIOPSY)IS
UNAVAILABLE ,THE DNA PATTEN MAY BE
COMPARED TO A PARENT OR TO A SIBLING
EXTRACTION OF DENTAL DNA
• PULPAL TISSUE BEST SOURCE OF DENTAL
DNA
• CRYOGENIC GRINDING FOR EXTRACTING
DNA(COOLING THE WHOLE TOOTH TO
EXTREMLY LOW TEMPERATURE,AND THEN
MECANICALLY GRINDING IT TO FINE
POWDER)TOOTH WILL BE COMPLETELY
CRUSHED
• ANOTHER METHODDRILLING OF THE
ROOT CANALS, SCRAPING THE PULPAL
AREA WITH A NOTCHABLE MEDICAL
NEEDLE,AND SUBSEQUENT FLUSHING OF
THE TIISSUE DEBRIS
TYPES OF DNA
• TWO TYPES OF DNA
1)GENOMIC OR NUCKEAR DNA
2)MITOCHONDRIAL DNA (mtDNA)
• EACH CELL HAS A HIGH COPY OF mt
DNA ,ALSO EXCLUSIVELY INHERITED
FROM MOTHER;NO CONTRIBUTION
FROM FATHER
• THUS IDENTICAL mtDNA IS OBSERVED
IN SIBLINGS, THEIR MOTHER AND
MANY MATERNAL RELATIVES
THE PALATAL RUAE IN
IDENTIFICATION
• USEFUL IN EDENTULOUS PERSONS
• RGAE 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 REOVERED FROM THE DECEDENT’S
RESIDENCE,OR PLASTER MODEL FROM
DENTAL OFFICE
CLASSIFICATION OF PALATAL RUGAE
• LYSELL MEASURED RUGAE IN ASTRAIGHT
LINE FROM MEDIAL TO LATERAL AND
CATEGORIZED AS
-PRIMARY RUGAE (>5mm)
-SECONDARY RUGAE(3-5mm)
-FRAGMANTARY RUGAE (2-3mm)
(RUGAE <2mm IS NOT TAKEN IN TO
CONSIDERATION)
• THOMAS &KOTZE HAVE FURTHER DETAILED
VARIOUS PATTERNS OF PRIMARY RUGAE –
BRANCHED ,UNIFIED , CROSSLINKED ,
ANNULAR , &PAPILLARY
ANALYSIS OF RUGAE PATTERNS
• THOMAS AND VAN WYK HAVE
MANUALLY TRACED RUGAE PATTERN
ON PHOTOGRAPHS OF PLASTER
MODEL
• RECENTLY, LIMSON AND JULIAN HAVE
DEVELOPED A COMPUTER SOFT
WARE PROGRAM,’RUGFP-ID
MATCH’(SAME PRINCIPLE OF FINGER
PRINTING)
DENTAL PROFILING
• WHEN ANTE-MORTEM RECORDS ARE
NOT AVAILABLE
• INCLUDES A TRIAD OF
INFORMATIONETHNIC ORIGIN ,
GENDER , AGE
• INFORMATION FROM THIS PROCESS
WILL ENABLE A MORE FOCUSSED
SEARCH FOR ANTE-MORTEM
RECORDS
IDENTIFY ETHNIC ORIGIN FROM THE
TEETH
• HUMAN RACES HAVE BEEN DIVIDED IN
TO THREE RACES CAUCASOID,
MANGALOID AND NEGROID
• IT IS POSSIBLE TODAY TO IDENTIFY
AN INDIVIDUAL’S ETHNIC ORIGIN
BASED PURELY ON ONE’S DENTITION
GENETIC AND ENVIRONMENTAL INFLUENCE
ON TEETH
• DENTAL FEATURES HAVE COMPLEX MODE
OF INHERITENCE AND ARE COMBINATION
OF HERIDITY AND ENVIRONMENTAL
FACTORS TO WHICH PERSON IS EXPOSED
• SO DIFFERENT POPULATION SHOW
CONSIDERABLE VARIATION
• DENTAL FEATURES IN POPULATION DIVIDED
IN TO
1)METRIC(TOOTH SIZE)
2)NON METRIC(TOOTH SHAPE)
:MORE HERITABLE&DEPENDABLE
NON METRIC DENTAL
FEATURES
CROWN FEATURE
SHOVELLING,DOUBLE SHOVELLING,CAREBELLI’S
FEATURE,THREE CUSPED UPPER 2ND MOLAR,CUSP
5, CUSP 6,CUSP 7, WINGLING,FIVE -CUSPED LOWER
SECOND MOLAR, LOWER MOLAR GROOVE
PATTERN,INTERRUPTION GROOVE, ENAMEL
EXTENSION, ODONTOME, LETAREL INCISOR
VARIATION, DISTAL ACCESSORY RIDGE, PREMOLAR
ACCESSORY RIDGE, PREMOLAR ACCESSORY
MARGINAL TUBERCLE, PREMOLAR LINGUAL CUSP,
MESIAL MARGINAL TUBERCLE OF UPPER MOLAR,
PARASTYLE, PROTOSTYLID
ROOT FEATRES
TWO ROOTED UPPER PREMOLAR
TWO ROOTED UPPER MOLAR
TWO ROOTED LOWER CANINE
TOMES ROOT
THREE ROOTED LOWER MOLAR
SINGLE ROOTED LOWER MOLAR
OF THESE NON-METRIC DENTAL FEATURES
SOME HAVE HIGH FREQUENCY IN CERTAIN
POPULATION AND OTHER UNCOMMEN
Eg: SOUTH-ASIAN’S EXHIBIT 4 CUSPED LOWER
SECOND MOLAR BUT FEATURES LIKE WINGLING
,SHOWELLING,Y GROOVE PATTERN TOMES
PATTERN
SEX DIFFERANTIATION
• SECOND STEP
• CAN BE DETERMINED
1)SEXING FROM CRANIOFACIAL
MORPHOLOGY AND DIMENSION
2)SEX DIFFRENCES IN TOOTH SIZE
3)DENTAL INDEX
4)SEX DETERMINATION BY DNA
ANALYSIS
5)SEX DETERMINATION BY DNA
ANALYSIS
CRANIOFACIAL MORPHOLOGIC INDICATOR OF SEX
Skull features
CRANIAL MEASUREMENT (IN MM)USEFUL IN SEXING
ODONTOMETRIC DIFFERENCES
DENTAL INDEX
Dental Age Estimation
• Final step in dental profiling
• Estimation methods
1). Age estimation in prenatal, neonatal and
early post natal child
-by use of histologic technique (12 weeks before it
is actually apparent on radiographs)
-by radiograph-non invasive
-neonatal line indicates a live births
-by dry weight of mineralized tooth (at six month
IU- 60mg, newborn-0.5g, six month post natal-1.8g)
2.Age estimation in children and adolescents
-two events may be usederuption and tooth
calcification
-various methods
a). Schowur and Massler’s method: described 20
chronological stages of tooth development starting
from 4 months IU until 21 years of age. It is based on
histological section which permits direct comparison
with radiographs
b).Demirjan’s method: made use of a foreign
system. Devolopment of Left side seven mandibular
teeth was devided into 8 stages(A-H). Each tooth
assaigned a” maturity score” and total maturity score
of all teeth is plotted on a chronologic age
conversion table. Separate maturity score and age
conversion table for both sexes.
c). Third molar in age estimation: A valuable
indicator in the age 16-23 years. but questionable now a days due to
great variation in genesis, position, morphology and time of formation.
3). Age estimation in adults
challenging when compared to young age groups as numerous endogenous
and exogenous fqactors, such as disease, nutrition, physical strain
influences.
a). Methods:
Gustafson’s method: based on morphological and histological changes of
the teeth. Accessed regressive changes such as:
.amount of occlusal attrition (A)
.coronal secondary dentin deposition(S)
.loss of periodontal attachment(P)
.Cementum aposition at the root apex(C)
.Root resorbtion at apex(R)
.dentin translucency (T)
Each of regressive changes have seven grades (0,0.5,1,1.5,2,2.5,3)
Age = 11.02+(5.14A)+(2.3S)+(4.14P)+(3.71C)+(5.57R)+ (8.98T)
b). Dentin translucency: root dentin starts to
become translucent during the third decade of
life beginning at the apex and advancing
coronally. Hence as age advances refractive
index between intratubular organic and extra
tubular inorganic material is equalized resulting
in increased translucency of the affected dentin
zone.
Age= B0+B1X where B0 –regression constant
B1-regression coefficient
X-length of translucency
C).Age Estimation from
Incremental Lines Of Cementum
• From acellular cementum incremental lines
• Made us of mineralized unstained crosssections of teeth
D).Radiographic Method:
• Used pulp size mesurement of six teeth
521 125
421 124
Age = 129.8-316.4(M)-66.8(W-L)
• The measurement include several length and
width ratios such as:
pulp-root length P
pulp-tooth length R
pulp-root width at CEJ A
pulp-root width at mid-root level C
pulp-root width at mid-point between level C
and A  B
mean value of all ratio including
excluding T M
mean value of width ratios B and C W
mean value of length ratio p and R L
Age = 129.8-316.4(M)-66.8(W-L)
Amino acid recemisation
• Suggested a relationship between dentinal age
and extent of aspartic acid recemisation in
dentin.
• Aspartic acid undergo rapid rate of
recemisation and get spontaneously converted
from L-Aspartic acid to D-Aspartic acid with
increasing age.
• Comparing D-L ratio age can be estimated.
Cranio-facial estimators of age
• Cranial suture and also mandible provides certain
characteristic for elicitation of age
Surture
Sagittal
Sphenoparietal
Coronal
Squamosal
Sphenotemporal
Lambdoid
Mastooccipetal
Sphenofrontal
Endocranial
initiation
21
30
25
37
30
26
26
24
Ectocranial
termination
35
65
39
80
68
41
72
35
BODY
INFANCY
ADULT
shallow
Thick & long shallow
RAMUS
OLD AGE
Forms an
obtuse angle
with the body
MENATAL Located near
FORAMEN lower margin
of the body
Forms an
approximate
right angle
Midway
between
upper and
lower
margin
CONDYLE Occupies a
Elongated and Neck is bent
projects
backwards
above the
coronoid
lower level to
the coronoid
process
Obtuse
angle
Near
alveolar
margin
• ODONTOMETRIC DIFFERENCE
TOOTH MESIODISTA
L
NO.
M
11
12
13
14
15
16
17
8.9
7.0
8.3
6.9
6.7
11.0
10.4
MESIODISTA
L
F
8.5
6.65
7.6
6.8
6.65
10.6
9.9
BUCCOLINGUA
L
M
7.1
6.5
8.4
9.3
9.8
11.0
11.0
BUCCOLINGUAL F
7.0
6.2
7.9
8.9
9.3
10.9
10.7
TOOTH MESIODISTAL MESIODISTAL BUCCOLINGUA
L
NO.
M
F
M
BUCCOLINGUAL F
41
5.5
5.3
6.2
6.1
42
6.1
5.9
6.5
6.5
43
7.2
6.6
7.55
7.4
44
7.1
7.0
7.9
7.6
45
7.4
6.9
8.6
8.2
46
11.1
10.8
10.4
10.2
47
10.5
10.2
10.3
9.9
• Cranial measurement (in mm) useful in sexing
• CRANIAL VARIABLES
Males
Females
Cranial base length
112.5
103
Mastoid height
12.5
9.6
Mastoid width
24
19
Total face height
127
114
Bizygomatic breadth
129
122
Basion-nasion length
102
96
Cranial length
188
179
Nasal height
54
50
Maximum frontal width
120
115.5
• Cranial measurement (in mm) useful in sexing
• MANDIBLE VARIABLES
Male
Female
Bicondylar breadth
117
111
Bigonial breadth
100
91.5
Minimum ramus breadth
31
28.5
Gonion-gnathion breadth
77
73
Total mandibular length
111
108
CRIME INVESTIGATION
BITE MARKS:
• A mark caused by teeth either alone or in combination
with other mouth parts (Mac Donald).
• May be caused by humans or animals; 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.
Classification of bite marks
1.Cameron and Sims Classification
Agents
Humans
Animals
Materials
skin,body tissue
food stuff
other materials
2.Mac Donald’s classifications
Tooth pressure mark
Tongue pressure mark
Tooth scrape mark
3. Webster’s classification
Type I
Type II
Type III
Bite mark appearance
• Type of injury
• Identifying The Injury As a Bite Mark
a). Gross features: Circular or ellipticalwith central area of
ecchymosis
b). Class features: Incisorrectangular
Caninestriangular or rectangular
Premolars and molars spherical or point shaped
c). Individual features: Class features intern
have
characteristics such as fractures
rotation etc.
• Site of Bite Marks
Females on breast, legs( inner part of thigh)-sexual
assault
Male children genitals-child abuse
Adult Males finger, arms and shoulders-fight
Bite mark investigation
• Preliminary questions
• Bite mark evidence collection from the victims
if criminal in nature is reported to law
enforcement
agencies
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
5.Evidence collection from suspect: using a
signed and informed consents or a court
order (warrant) also include photograph, two
casts, bite registration in centric occlusion and saliva
swab from buccal vestibule
Bite mark analysis and comparison
•
•
•
•
•
Jaw movement
Flexibility of bitten tissue
Individual features of bite marks
Metric analysis
Computer software program
Conclusion Of Bite Mark Analysis
• Positive identification
• Possible identification
• Excludes identification
Investigating Animal Bites
• Characteristics of some vertebrate dentition
fish conical, homodont, heterodont or
polyphydont
Reptiles homodont conical or only
tricuspid teeth
Venomous snake single row, palatal
to this are two poison fangs containing
canal or groove for venom release
Non-Venomous two rows of maxillary
teeth
Mammals heterodont dentition, diphyodont also
have accesssional teeth( permanent molar emerge
posterior to deciduous teeth)
carnivores i
Lip Prints
•
•
•
Examination of lip print-cheloscopy
Grooves an wrinkles visible on lips named as sulci, labiorum rubrorum
Grooves are heritable and suppose to be individualistic so material evidence left at a crime scene
similar to finger prints
•
Lip prints classified as
I) a) simple wrinkles
straight line
curved line
angled line
sine shaped curve
b) compound wrinkles
Bifurcated
trifurcated
anomalous
II)type 1- clear cut vertical grooves that run across the entire lip
type 1’-similar to type 1 but not cover the entirely
type 2- branched grooves
type 3- intercepted grooves
type4- recticular grooves
type 5- grooves that can not be morphologically differentiated
•
Invisible prints can be lifted using materials such as aluminum powder, magnetic powder
DISADVATAGE
1. Trauma, pathosis, surgical treatment can affect the size and shape of the lip
2. The zone of transition close to vermilian border is extremely mobile so prints produced may differ
depending on pressure applied and its direction
DENTIST AS AN EXPERT
WITNESS
• Expert witness are those whose training,
qualification or experience enables them to give
an opinion on relevant matter where the
ordinary person is not so enabled.
• To become dental expert to forensic dental
expert need additional knowledge and
experience