GOOD MORNING

Father of Forensic Science

Good morning

Forensic Odontology�

Contents

• Introduction
• History
• Personal identification
• Age estimation
• Dental
• skeletal
• Sex determination
• Dental
• skeletal
• Mass disaster Management

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• Bite marks
• Cheiloscopy
• Rugoscopy
• Ameloglyphics
• Conclusion
• References

KEISER and NEILSON (1970)

It is a branch of odontology which deals with the proper handling and examination of dental evidence and the proper evaluation and presentation of dental findings in the interest of justice

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FDI says…

“ 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 & presentation of dental findings ”

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Latin words:

Forensis=before the forum or court of law,

Odontos =related to tooth logos=knowledge Odontology=study of teeth

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• ‘‘What a nightmare!. . . bodies as of negroes – blackened; heads carbonised; shrunk and reduced to nothing , but only the teeth remained.”

-Dr. Oscar Amoedo

The father of Forensic Dentistry

History….. .. .

The very first case!

Julia Agrippina- Roman empress

1^ST

66 AD

discolored front tooth

1897

• “The role of the Dentists in the identification of the victims of the catastrophe of the Bazar de la Charite, Paris and 4th May, 1897”, was presented by Dr. Oscar Amoedo at the international Medical Congress of Moscow

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• When 30 remaining corpses – identified by the dentists of the missing persons

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• Dr. Oscar Amoedo incorporated many concepts of dental identification in a text- “L'ART DENTAIRE EN MEDECINE LEGALE” published in French in 1898 and in German in 1899.

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ADOLF HITLER

bridge with nine units

Where is it used?

CIVIL:

1. Malpractice and all aspects which may eventually lead to criminal charges in the form of fraud.

2. Neglect, where damages may be sought

3. Identification of individual remains where death is not due to suspicious circumstances- whether fragmentary or complete. It includes each assessments

4. Identification of a living person.
5. Major or mass disasters- the identification of victims of an aircraft or train disasters or fire in a public building

CRIMINAL

1. The identification of persons from their teeth - living/dead person.

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2. Bite marks - food stuff, on the assailant, on the victim- self inflicted/inflicted by another

RESEARCH

1. Academic training and courses

2. Post graduate tuition

i.e .. . Every contact leaves a trace

Identity

The characteristics by which a person may be recognized.

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IDENTIFICATION

1. Non dental identification

2. Dental identification

NON DENTAL IDENTIFICATION :

• Facial recognition by relatives or acquaintance
• personal property (Clothing, Jewellery, etc.,)
• Finger printing – (A.M. records must)

- can be taken from household surroundings

• Other bones of the body

- Pelvic Bones

- Hand Wrist X-ray

Three Main forms of Dental Identification

1. Comparative identification

- most frequently performed examination

- to establish the remains of a decedent and a person represented by ante mortem records are of the same individual.

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2. Reconstructive identification [Dental profiling or Post-mortem Dental profile]

- elicit race, gender, age & occupation of the dead individual

- undertaken when ante-mortem records are not available.

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3. Identification in mass disasters

- identification of victims in mass disasters

Comparative Dental Identification�

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- Conventional method of identification

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- includes four steps

A) Oral Autopsy

B) Obtaining Dental Records

C) Comparing post and ante-mortem dental records

D) Writing a report & drawing conclusions.

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• ORAL AUTOPSY

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• Necropsy / post mortem examination

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• dissection to expose the organs, to determine the cause of death

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• oral examination – essential part

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• Forensic dentist should have knowledge about rigor mortis [stiffening & rigidity], livor mortis [purple discoloration on the skin in the dependent parts], decomposition & postmortem artifacts

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• For jaw separation, use of mouth gags, trismus screws or intra oral myotomy is essential.

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• Radiographs must be taken

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• Thorough examination of soft tissue injuries, fractures & foreign bodies

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• information be entered on to the standard ‘Interpol Post-Mortem form’ – Color coded in Pink.

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• OBTAINING DENTAL RECORDS

[Ante-mortem records]

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• Contains information of treatment & dental status during his/her life.
• Obtained from treating dentist, specialist or hospital records – in the form of dental charts, radiographs, casts & / or photographs

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• Transcribed onto the standard ‘Interpol ante-mortem form’ – color coded in Yellow.

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• COMPARING POST – AND ANTE-MORTEM DENTAL RECORDS
• Compared by written notes, Study casts, radiographs, Photographs etc.,
• Criteria for comparison are
• Tooth characteristics [number, eruption status, position]

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• Personal characteristics

[crown morphology - occlusal ridges, cusps,

Root morphology - branching pattern, furcation, fusion]

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• Complexity factors – tubercles, pits, additional ridges, grooves, fissures

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• Acquired features – hypoplasia, trauma, function, personal habits, restorations

• Individual with multiple dental treatment & unusual features – better identified.
• Dental record considered a legal document
• Radiographic identification is often conclusive.

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DISCREPANCY BETWEEN THE TWO RECORDS COMPARED SHOULD HAVE AN EXPLANATION.

The Post-mortem Records

• Made using diagrammatic charts, tape recordings, radiographs, photographs & / or models.

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• A number of computer software programs such as IDENTIFY, ODONTID, CAPMI and IDIS have been developed over the last two and a half decades to simplify comparison.

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• In addition, the Interpol has facilitated access to and free use of a software program called ‘Plass Data DVI System International’

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UNUSUAL WEAR AND TEAR

ATTRITION, EROSION, ABRASION

ABRASION:

• if confined to enamel -<30 years
• if reached dentin – 30-40 years
• if extensive dentine – 40-50 years
• if occlusal surface flat – 50-60 years
• At the level of tooth neck- >60 years

Erosion

Abrasion

TEETH LOST BEFORE AND AFTER DEATH

• If margins of empty sockets are unresorbed and sharp means lost after death

• WRITING A REPORT AND DRAWING CONCLUSIONS

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1. Confirms identification / Positive identification

- Ante – and Post-mortem data match each other

- proven ‘beyond reasonable doubt’ with radiographs

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2. Probable identification

- Data is consistent but lacks quality ante & postmortem information ; no radiographs

3. Possible identification

- Explainable differences exist between the ante – and post-mortem data.

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4. Insufficient Information

- available information is minimal

5. Excludes identification

- Ante-and Post-mortem data are inconsistent with unexplainable differences - Indicates a mismatch

II. DENTAL PROFILING

[RECONSTRUCTIVE IDENTIFICATION (OR) POST – MORTEM DENTAL PROILE]

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It includes the decedent’s

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1. ETHNIC ORIGIN [Race determination]

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• GENDER [Sex determination]

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• AGE [Age estimation]

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IDENTIFYING ETHNIC ORIGIN FROM TEETH� [RACE DETERMINATION]�

• Caucasoid (White) race
• Negroid / Congoid (Black) race
• Capoid (Bushmen/Hottentots) race
• Mongoloid (Oriental/Amerindian) race
• Australoid (Australian Aborigine and Papuan) race

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Classification by American anthropologist Carleton S. Coon (mid-twentieth century)

DETERMINATION OF RACE

CHINESE:

1.Wide arch

2.Enamel extension

between roots of molars

3.Five cusped third molars

4.Rooted deciduous molars

EUROPEANS:

1. Narrow arch & crowding

2. Cusp of Carabelli

MONGOLOID:

1.Occlusal enamel pearls in premolars

2.Missing mand. incisors

3.Shovel-shaped incisors

AMERICAN INDIANS:

1. Marked attrition

2. Shovel-shaped incisors

3. Large teeth

SOUTH AFRICANS: Tall pulp chambers

COMMON RACIAL CHARACTERISTICS

IDENTIFICATION OF INDIVIDUAL’S ETHNIC ORIGIN BASED PURELY ON DENTITION

Dental features - Combination of hereditary & environmental factors

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Dental features are broadly categorized as

1. Metric [ Tooth size ] – Measurements
2. Non Metric [ Tooth Shape ]

- Presence or absence of a particular feature eg:- Cusp of carabelli

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1. METRIC FEATURES:-

Influenced by local environmental factors eg:- missing lat. Incisors causes compensatory increase in central incisors, Lack of space result in compression of third molars.

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2. NON METRIC FEATURES:-

- heritable, more dependable

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European, West & South Asian People

1. Four cusped lower 2^nd molar
2. Two rooted lower canine
3. Carabelli’s feature &
4. Three cusped upper 2^nd molar

East Asians

1. Winging 6. Enamel extensions
2. Shovelling 7. Three rooted mand. 1^st molar
3. Double shovelling 8. Three cusped max. 2^nd molar
4. Interruption grooves 9. Single-rooted mand. 2^nd molar
5. Odontomes

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B. SEX DETERMINATION

Pelvis is a better indicator of sex than the dentition.

1. SEX DIFFERENCES IN SKULL SIZE

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2. SEX DIFFERENCES IN TOOTH SIZE

Generally teeth are smaller in females

Teeth – used for differentiating sex by measuring mesiodistal & buccolingual dimensions

Canines – show max. sex difference

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Mand. Canines show greatest dimensional difference, being larger in males

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Dental Index

In addition to tooth size, tooth proportions have been suggested for differentiating the sexes.

Aitchison presented the ‘Incisor Index’ [Ii] calculated by the formula

Ii = MDI² MDI² is the max. MD diameter of Max. LI

MDI¹ MDI¹ is the max. MD diameter of Max. CI

Ii is higher in males

Standard Mandibular Canine Index Proposed by Rao & Assoc.

Mean mandibular canine index in female + S.D

Mean mandibular canine index in males – S.D + 2

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100

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3. TOOTH MORPHOLOGY AND SEXING

According to Scott & Turner II, ‘Distal Accessory ridge’ – a nonmetric feature on the canine – most sexually dimorphic crown trait.

Males shows significantly higher frequency & more pronounced expression than females.

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4. SEX DETERMINATION BY DNA ANALYSIS

a. From pulp tissue:- Y chromosome analysis from dental pulp of male can be done even after 1yr. Of death

b. From enamel protein [Amelogenin]:-

Amelogenin[AMEL] – Major matrix proteins secreted by the ameloblasts of the enamel

AMELgene located on X & Y – chromosomes in humans

c. From Buccal Mucosa:- Barr bodies & x-chromosomes of female detected from buccal mucosal epithelium.

AGE ESTIMATION

TYPES OF AGE:

• CHRONOLOGICAL AGE OR REAL AGE: It is the measured by the calender, whether it be a period of IU development or number of years after birth
• HEIGHT AND WEIGHT: Age of a person can be roughly determined from the standard charts of height & weight, but is least accurate & reliable
• SKELETAL AGE: Determined by the degree of ossification / development of various bones known to occur at particular time in average individual
• DENTAL AGE: Determined by studying development of various teeth from the time the crypt is visible till the time of root completion

SKELETAL AGE DETERMINATION

Age Changes in Craniofacial Bones

Neonatal : Edentulous jaws, orbit size relatively large

I year : Fusion of midline symphysis of mandible

Metopic sutures of two halves of frontal bone fuse

Lat. Sphenoidal synchondrose fuse

Fontanelles : Post & ant. Lateral fuse by 3 months.

Ant. Fontanelle by 1 ½ yr (18 MONTHS).

3 years : Condylar portion of occipital bone fuses with squamous

5 years : Condylar position of occipital bone fuses with basoocciput.

SPHENOOCCIPITAL SYNCHONDROSIS

[between basal part of occipital bone & adj. body of sphenoid] – Major skull cartilage centre, fuses by 18-21 years – most useful skeletal ageing factor.

Neonatal skull : in this neonatal skull the lack of eruption of the dentition places the age at less than six months after birth. The height of the face is small compared with an older child, whereas the relative size of the orbits is large. In most infants the midline symphysis of the mandible is fused by about one year after birth, and the lack of fusion in this specimen indicates a much lower age. The metopic suture (arrow) between the two halves of the frontal bone fuses at about one year, but there are racial variations.

• The fontanelles : the fontanelles of the skull may be an indication of age in that the anterior fontanelle is said to close by about one and half years of age, the posterior and anterolateral fontanelles by about one year. These dates are somewhat imprecise for particular individuals.

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• In this skull the anterolateral fontanelle (1) is still open, indicating that skull is less than three months after birth. The large anterior fontanelle(2) between the frontal and parietal bones closes at about 18 months of age. This structure may be readily seen on radiographs which provide a non invasive method of determining approximate age.

Skull cartilages: bones developing in cartilage can be used to age a skull. At the base of the skull the lateral sphenoidal synchondroses(1) are said to fuse within the first year of life, but the spheno-occipital synchondrosis(2), lying between the basal part of the occipital bone and adjacent body of the sphenoid, is a major growth centre until later life.

SKULL SUTURES

From 25 years- Coronal, Sagittlal, lambdoid sutures start closing

32 – 35yrs - Sagittal

40 yrs - Coronal

45yrs - Lambdoid

60yrs - Squamous portion of temporal bone fuses with parietal bone.

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CRANIAL SUTURES

Open - < 30 yrs

Closing - 30-55 yrs

Closed - > 55yrs.

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MANDIBULAR ANGLE

Infancy - 160 – 175⁰

1 – 3years - 150 - 160⁰

6 – 12years - 125 - 140⁰

15-17years - 120 - 130⁰

18-21years - 90⁰-125⁰

30-40years - 95⁰-115⁰

> 40 year - obtuse angle

• Evaluation of Cervical Vertebrae Maturity on Lateral Cephalogram

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• CVMI were evaluated by classifying C2, C3, and C4 into six groups depending on their maturation patterns on the lateral cephalogram using the classification of Hassel and Farman.

OSSIFICATION CENTRES

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From 2^nd month IU to

2^nd year of extra uterine life

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From 3^rd yr to mid teens – Secondary Ossification centres appear

Next decade- Primary Ossification centre (Diaphyses) unite with secondary ossification centres (epiphyses)

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Primary Ossification centres appear in the skeleton

MANDIBULAR CHARACTERISTICS USEFUL IN AGEING

DENTAL AGE ESTIMATION

Important Subspeciality of forensic sciences

Also has application in living individuals

Dental Age Estimation Methods

1. Morphologic / visual Examination
2. Radiographic Examination
3. Histological Examination and
4. Biochemical Examination

Age estimation using the dentition may be grouped into three phases

1. Ageing in prenatal, neonatal & early Post natal
2. Age estimation in children and adolescents
3. Age estimation in adults

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FACTORS USEFUL IN DENTAL AGE ESTIMATION

1. Appearance of tooth germs
2. Earliest detectable trace of mineralization
3. Degree of Completion of unerupted teeth
4. Rate of formation of enamel and formation of the neonatal line
5. Clinical eruption
6. Degree of completion of the roots of erupted teeth
7. Degree of resorption of the roots of deciduous teeth
8. Attrition of the crown

9. Formation of physiologic secondary dentin

10. Formation of cementum

11. Transparency of root dentine

12. Gingival recession

13. Root surface resorption

14. Discoloration and staining of the teeth

15. Influence of disease or malnutrition on tooth eruption

16. Influence of Sex on tooth eruption

17. Changes in the chemical composition of the teeth

Dental & skeletal ages correspond closely in males

In females, the skeletal age is one year ahead of dental age.

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Some odontologists advocate, the use of aspartic acid racemization, claiming an accuracy of ±4 years

Additional methods include the use of SEM-EDXA, a method used to examine dentine in relation to age determination

A recent study from the UK examined the use of root length, in the determination of age in paediatric cases

1. AGE ESTIMATION IN PRENATAL, NEONATAL AND EARLY POST NATAL CHILD

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1. Primary tooth germ begins to form at seven weeks in utero(IU) & enamel formation of all deciduous teeth complete by first year.
2. Permanent tooth germ begins to form at 3.5 to 4 months IU
3. Prenatal age estimation uses histological techniques, enables observation of tooth mineralization upto 12 weeks before it is apparent on radiographs.

4. Neonatal line – indicator of birth

- slowing down of enamel prism growth rate, thus creating an apparent line of demarcation.

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5. Amount of enamel & dentin before & after birth taken as basis , enamel & dentin formed after birth divided by daily rate of formation 16µm/day indicates approximate age.

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B. AGE ESTIMATION IN CHILDREN AND ADOLESCENTS

1. Tooth emergence or Eruption

2. Tooth calcification

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1. ERUPTION:- Convenient clinical method

visual assessment of teeth & compared with radiographs & charts.

Main drawback is emergence patterns are under the influence of intraoral environment [infection, arch space, premature tooth loss]

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2. CALCIFICATION:- better alternative, since,

a. Calcification can be observed for a period of several years from

radiographs

b. not altered by local factors

c. assess age at periods when no emergence

takes place [2.5 – 6yrs & more than 12yrs]

Methods for estimating age in Children and adolescents

1. SCHOUR AND MASSLER’S METHOD:-

Charts describes 20 chronological stages of tooth development starting from 4month IU until 21yrs of age.

Ubelaker’s improved charts should be used since the original Schour & Massler chart had serious drawbacks

2. DEMIRJIAN’S METHOD:-

- made up of scoring system

- development of seven mand.teeth was divided into eight stages each [A to H].

- each tooth is assigned a maturity score that corresponds to its developmental stage.

- maturity score for each tooth is added and a total maturity score obtained

- Total maturity score is plotted on a chronologic ‘age conversion table’ [Separate for both sexes

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3. THIRD MOLARS IN AGE ESTIMATION:-

All four third molars are calcified, the chances of the individual being 18yrs old is 96.3% in males & 95.1% in females

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Van Harden developed five stage system measuring mesial root of developing mand 3^rd molar

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Stage 1:- Crown complete, 16.8 – 16.9yrs

Radiographic

evidence of root

formation

Stage 2:- Root length >1/3 <1/2 17.5 years

Stage 3:- Root length >2/3 17.8 – 17.9 yrs

but not complete

Stage 4:- Root fully formed 18.4 – 18.5yrs

with open apex

Stage 5:- Apex closed 18.9 – 19.2yrs

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C) AGE ESTIMATION IN ADULTS

Most of the methods in adults use various regressive changes of hard and soft tissues of the teeth. Less accurate compared with estimation <20yrs.

I. GUSTAFSON’S METHOD OF AGE ESTIMATION

In 1950, Gosta Gustafson developed age estimation method based on morphological and histological changes of the teeth.

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1. Amount of occlusal Attrition (A)
2. Loss of periodontal attachment (P)
3. Coronal secondary dentin deposition (S)
4. Root resorption at the apex (R)
5. Dentine translucency (T)
6. Cementum apposition at the root apex (C)

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For each regressive changes, 0-3 scores were assigned

0 - unchanged (from development completion stage)

1 - Minimal Change

2 - Moderate change

3 - Severe changes

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A

P

S

R

T

C

The points awarded to each feature are added

(e.g. A3 + S2 + P2 + C1 + R2 + T1 =X)

↑ in total score (X) → ↑ in age

Age was estimated using the formula

Age = 11.43 + 4.56 X with an average error of 3.6yrs.

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Maples and Rice Corrected the above formula

as Age = 13.45 + 4.26 X

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According to Johanson

Instead of four grades (0-3), he proposed seven grades (0, 0.5, 1, 1.5, 2, 2.5 & 3). Using these grades

Age = 11.02 + (5.14A) + (2.3S) +(4.14P) + (3.71C) + (5.57R) + (8.98T) was suggested

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II) DENTINE TRANSLUCENCY

• Bang & Ramm – first to use dentine translucency for age estimation
• Root dentine starts translucent during 3^rd decade of life, begins at the apex & advances coronally.

Solheim suggested translucency length (in mm) or area (mm2) measured on intact or sectioned teeth.

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Two equations were given

Age = B₀ + B₁ + B₂ X² for zones of translucency ≤ 9mm

Age = B₀ + B₁ X for zones of translucency >9mm

Where B₀ is regression constant, B₁ & B₂ are regression coefficients, X is the translucency length.

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Disadvantages:-

1. Irregular junction of translucent & non translucent zones.
2. Under estimation of age in old age groups due to slowing down of dentinal sclerosis, restricting further ↑ in translucency

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III) AGE ESTIMATION FROM INCREMENTAL LINE OF CEMENTUM

Kagerer & Grupe suggested age estimation from acellular cementum incremental lines.

Mineralized unstained cross-sections of teeth [preferably mand. CI & 3^rd molars] are used.

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Disadvantage:-

Necessity to extract and / or section the teeth

possible in the dead but not in living individuals.

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IV. RADIOGRAPHIC METHOD OF KVAAL AND ASSOCIATES

Developed a method that used Pulp size measurement of Six teeth (Max CI & LI, 2^nd PM, Mand CI, LI, canine & 1^st PM) on periapical radiographs.

Pulp - Root length (P)

Pulp - tooth length (R)

Tooth - Root length (T)

Pulp - root width at CEJ (A)

Pulp - root width at mid root level (C)

Pulp - root width at midpoint between level C & A (B),

Mean value of width ratios B and C (W)

Mean value of length ratios P and R (L)

Mean values of all ratios excluding T (M)

Regression formula,

Age = 129.8 – 316.4 (M) – 66.8 (W-L)

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V. AMINOACID RACEMISATION

Aspartic acid gets converted from L-Aspartic acid to D- Aspartic acid with increasing age.

• Constant change in the ratio of L-and D Aspartic acid at different ages.

Recemization rate of aspartic acid is high in root dentin – teeth are valuable source for ageing

• accurate, with age estimates with in + / - 3 yrs of actual age.

VI. OTHER METHODS

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Age estimation from changes in tooth color

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Martin–de las Heras & co workers proposed the use of spectro radio metry for dentin color measurements.

Dentinal colors white, cream & yellow : 12 – 37yrs

Dentinal colors dark yellow & brown : 55 – 64yrs.

Kvaal & Solheim suggested the use of dentin & cementum fluorescence for age estimation

↑ deepening of tooth color - ↑ fluorescence intensity - ↑ in age.

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Identification in Mass disasters

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Disasters: refers to natural calamities such as earthquakes, floods and tsunami and accidental or man-made events such as airplane crashes or terrorist attacks-that result in multiple human fatalities. Such incidents require identification of the postmortem remains due to severe mutilation.

• The process of dental identification involves examining and comparing hundreds, sometimes thousands, of ante and postmortem data.
• Human remains in such events may be highly fragmented and, hence, only part of the body may be recovered. The bodies may be incinerated or commingled, i.e. parts of two bodies are mixed with each other.

• Forensic dentists are usually part of a team of identification specialists that include anthropologists and fingerprint experts, to name a few.
• Each team has its own section where postmortem identification is carried out.
• According to Clark, almost 50% of identifications in disasters are from dental evidence. Therefore, most disaster identifications have an odontology section.
• Vale and Noguchi suggest the division of the dental section into three sub sections- postmortem unit, antemortem unit and comparison and identification unit.
• Clark states that dental examination is usually done after most other procedures such as photography, fingerprinting and medical autopsy.

Pink teeth

• Distinctive purplish pink color that is due to accumulation of blood breakdown products in the dentinal tubules
• It appears to take from 7 to 14 days before discoloration becomes apparent so this may give some gross indication of time of death
• But the knowledge of this phenomenon is still incomplete

• Violent death such as strangulation may raise the venous pressure immediately before death to such an extent that small capillaries in the pulps of the teeth rupture releasing red blood cells into the pulp and possibly into the dentinal tubules
• In forensic practice the phenomenon is most frequently seen in victims of drowning, in whom the head frequently lies in a dependent position.

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Teeth in Fire - Morphologic and Radiographic Alterations

Priyanka et al., J Forensic Res 2015, 6:2

IDENTIFICATION FROM DENTAL DNA

Teeth - Excellent source of DNA

PCR (Polymerase chain reaction)

• amplifies highly degraded DNA

compared with ante-mortem sample of the decedent (hair from a hair brush, epithelial cells from a tooth brush or a biopsy specimen)

Major Advantage:

• DNA Pattern may be compared to a parent or a sibling, if ante-mortem sample is unavailable.

Extraction of Dental DNA

CRYOGENIC GRINDING –

• Coding the whole tooth to extremely low temp., using liquid nitrogen & grinding it to fine powder.
• Major drawback is tooth needs to be completely crushed.
• Less destructive method is drilling the root canals & scraping the pulp area.

Types of DNA

1. Genomic or Nuclear DNA – Commonly used
2. Mitochondrial DNA (mt DNA) – substituted if nuclear DNA is unavailable

- inherited from mother

- high no. of mt. DNA in each cell

Bite marks

Bitemarks may be defined as marks having occurred because of either a physical alteration in a medium caused by the contact of teeth, or a representative pattern left in an object or tissue by the dental structures of an animal/human

• McDonald et al (1981) States that bite mark injuries are a form of "patterned injury" which means that the configuration is caused by a particular object.
• Sometimes bitemarks are called as "toolmarks".

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• Bite mark is defined as "a mark caused by the teeth either alone or in combination with other mouth parts.“ (MacDonald)

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• Bite marks may be caused by humans or animals; they may be on tissue, food items or on objects.

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• 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.

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• As a result, bite marks are usually associated with sex crimes, violent fights and child abuse.

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• Bite marks have even been recovered from scenes of theft.
• Hence, matching the bite mark to a suspect's dentition may enable the investigating officers to implicate the suspect in a crime.
• Sweet and Pretty consider the size, shape and pattern of the incisal or biting edges of upper and lower anterior teeth to be specific to an individual.

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• Rawson and associates have mathematically calculated that biting edges (incisal edges) of the twelve anterior teeth can be arranged in 1.36 X 10²⁶ different combinations.
• a bite mark may accurately depict the 'unique' pattern of a biter's teeth.

• Human bite marks is one among the most violent crimes tried in the criminal courts.

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• Bites have been found in cases of homicide, attempted suicide, sexual assault and child abuse.

• Bites can occur on both the victim and the suspect: teeth are used as weapon by the aggressor and in self defence by the victim.

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• Although they are only a small portion of most forensic dentists case load, bite marks represent the most challenging aspect of the discipline.

• Definitions of Marks in Forensic Dentistry (Jakobsen)

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• Tooth mark - Mark left by a tooth

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• Arch mark - Mark produced by four or five adjacent teeth in the same arch.

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• Bite mark- Tooth marks produced by antagonistic teeth

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Anatomic location

1. Bite marks are found on almost all areas of the body.

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2. It is common to find more than one bite mark on a victim,

often in different anatomical locations.

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3. Bite marks occurred primarily in sex-related crimes,

child abuse cases and cases involving physical alterations

of various types.

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4. Female victims are most commonly bitten on the breasts, arms and legs in descending order of frequency, and males most frequently bitten on the arms, back and hands(more often due to fights). Male children – genitals

Differences between human and carnivore bites�

• Compiled from Sweet (1995) and Brown (1992).

Classification of bite marks

• Cameron and Sims Classification.

based on the type of agent producing the bite mark and the material exhibiting it.

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Agents

• Human

• Animal

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Materials

• Skin, body tissue

• Foodstuff

• Other materials.

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• MacDonald's Classification.
• suggested an etiologic 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.

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• Tongue pressure marks: When sufficient amount of tissue is taken into the mouth, the tongue presses it against rigid areas such as the lingual surfaces 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.

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Bite marks on cheese

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.

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Identifying the Injury as a Bite Mark�

• Sweet has suggested that a human bitemark may be identified by the following characteristics:

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Gross charateristics

• A circular or elliptical mark found on the skin with a central area of ecchymosis.

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• The circular/elliptical mark is caused by the upper and lower arches while the central area of ecchymosis is apparently due to sucking action.

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• A typical bite mark is usually distinct from an injury caused by anything else.

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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.

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• Incisors produce rectangular marks; canines are triangular or rectangular, depending on the amount of attrition; premolars and molars are spherical or point-shaped.

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Individual charateristics

• Class charateristics may, in turn, have features such as fractures, rotations, spacing, etc.

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• Such attributes are referred to as individual features and make the bite mark distinct.

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• Description of some types of bite marks:

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• Sexually Oriented bites: Sexually oriented bites appear to have been inflicted slowly and deliberately with suction applied to the tissue by tongue and lips.

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• The resultant injury exhibits central or peripheral "suck marks" and marks of- anterior teeth with good definition.

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• The amount of distortion may indicate whether the person being bitten was active or passive when the bite mark was being inflicted.

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• Child abuse cases: In the child abuse cases either aggressive (anger bite marks) or sexually oriented type of bite marks are seen.

• Self inflicted bite marks: Mostly found on the forearms of children caused by themselves.
• Sometimes arms may be pushed into the child's mouth to stop crying or due to intense pain, children may bite themselves because of fear.
• Mentally retarded and psychologically disturbed people may also inflict bite on themselves. Self inflicted bite marks are also seen in Lesch-Nyhan syndrome, an X-linked, recessively transmitted disease with insensitivity to pain.

Sexually Oriented bites

• Factors influencing the bite marks:

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• Type of tissue: In the case of skin, if it is loose or with excessive fat bites commonly produce bruising leading to poor definition.

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• Whereas in areas of fibrous tissue or with high muscle content tend to bruise less, so that the definition of bite mark is good.

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• Age: Infants and old individuals bruise more than other age groups.

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• Sex: Females tend to bruise more than males. Once produced bitemarks will be evident for longer period of time in females compared to males.

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• Medical status: People having bleeding disturbances, under anticoagulant therapy and certain skin diseases bruise more.

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• Time: The time elapsed between actual biting and when the impression is made is vital. Depression produced in the skin due to bitemarks will recover within 10-20 minutes leaving swelling and discoloration. After death skin tends to contract, harden and decompose

• Enzyme histochemistry:
• According to Rae Kallio, the appearance of various enzymes from the time of injury are as follows:

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• ATP-ase : 1 hour after injury.

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• Esterase : 1 hour after injury.

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• Acid phosphatase : 4 hours after injury.

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• Alkaline phosphatase : 8 hours after injury.

• Bite mark cases have to be dealt step by step in the following way:
• Description of bite marks.
• Collection of evidence from the victim.
• Collection of evidence from the suspect.
• Bite marks comparison.

I. Description of bite marks:

Both in the living and deceased victims the following vital information should be recorded.

1. Demographics:

Name, age, sex, race, case number, date of examination, and name of the examiners should be recorded.

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B. Location of the bite mark:

Describe the anatomic location, indicate the contour of the surface as flat, curved or irregular and state the tissue characters

Skin - fixed or mobile.

Underlying tissue - bone, cartilage, muscle or fat.

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C. Shape of the bite marks:

whether it is round, ovoid, crescent or irregular in shape.

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D. Color of the mark:

E. Size of the mark:

Both vertical and horizontal dimensions should be recorded in metric system.

F. Type of injury:

Type of tissue injury due to bite mark may be,

Petechial hemorrhage

Contusion

Abrasion

Laceration

Incision

Avulsion

or an Artefact.

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G. Note the surface of the skin as smooth or indented.

II. Data collection from the victim:

Bite mark evidence should be gathered from the victim after obtaining authorization from the authorities. Determine whether the bite mark has been affected by washing, contamination, embalming, decomposition etc.

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Steps in the examination of the victim:

A. Visual Examination. Visually examine the bite mark and document the following:

• • Type of injury
• • Contour, texture, and elasticity of the bite site
• • Physical appearance (color and size), orientation, and location of the bite mark
• • Differences between upper and lower arches, and between individual teeth.
• If the victim is dead, visual examination must be done before an autopsy.

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B. Photographs of the bite marks should be made immediately.

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• provide a permanent record of the appearance of bite marks.

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• No time should be lost in obtaining photographs, as the injury rapidly changes appearance due to healing.

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It is advisable to have photographs from two views:

• Orientation photographs -These photographs depict the location of the bite mark on the body.

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• Close-up photographs -These photographs should be taken with a rigid reference scale that is placed in the same plane as the injury. The entire scale and bite mark must be visible in the photograph.

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C. Salivary swabbing:

The amount of saliva deposited with a bite mark is about 0.3 ml and distributed over a wide area of 20 mm. Practical points helpful in the collection of salivary swabbing are:

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One square centimeter piece of Rizla type of cigarette paper held in forceps is used after wetting it with fresh water or distilled water (contamination with fingers will give false positive result).

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• The whole bite mark and the adjacent area should be swabbed.
• Air dry the paper by placing it on a clear microscopic slide.
• After drying, swabs are packed and send to the laboratory.

• A control sample is prepared using same method as described above-but without swabbing with saliva.

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• Instead of using paper, a cotton piece can also be used for saliva swabbing.

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• Saliva obtained from swabbing is used to determine the blood group antigens.

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• Identification of the saliva is done by demonstrating it's amylase activity in hydrolyzing a starch substrate.

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• The presence of blood group antigens can be determined by absorption-elution or absorption-inhibition group testing.

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D. Impression of bite marks:

• If the bite marks have penetrated the skin, an impression of the marks should be made.
• A rubber base material such as vinyl polysiloxanes with dimensional stability should be used.
• Two methods are commonly used to make impressions.

• Method-1:
• Cover the bite area with 5mm thick light bodied material.
• Place a wire gauze over the set material.
• Inject additional material over it.
• After removal of the impression indicate the direction of head with marker on the back of the impression.

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• Method-2:
• A special tray is constructed using cold cure or orthopedic cast material confining to the shape of anatomic part in which bite mark is present.
• Impression is made using rubber base material.
• Master casts must be poured with type-IV stone and duplicate casts should also be made. Either visible light cure or epoxyresin clear material may be used to make stable rigid model.

Bite print recording:

• Similar to the methods used to lift finger prints from crime scenes, fingerprint lifting tape can be used to lift the "non-perforating" bite marks after brushing the bite mark with finger print lifting powder.

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Tissue samples:

• In the case of dead victims with bite marks, bite marks can be excised along with the underlying tissues after fixing an acrylic stent around the bite mark to avoid shrinkage of the tissue. Store the specimen in 4% formalin.

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The videotape documentation:

• The videotape documentation demonstrate the three dimensional picture of the bite in motion.

III. Examination of the suspect:

• Following details should be noted from the suspect after obtaining necessary consent.
• History of dental treatments after or just before the bite mark has to be noted.

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1. Photographs:
1. Full face, profile photographs, frontal, occlusal and lateral views of the dental arches should be taken.

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B. Examination:

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• TMJ . status, facial asymmetry, muscle tone, maximum opening of mouth, deviation while opening and closing movements have to be recorded under extra oral examination.
• Tongue movements, periodontal status should be noted. Special attention should be given to the arrangement of dentition.

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C. Saliva swabbing should be performed as described before.

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D. Upper and lower dental models should be prepared.

• Sample bites should be made whenever possible, simulating the type of bite under study.
• This may be recorded in wax sheet or in impression compound.

IV. Evaluation of evidence:

• American Board of Forensic Odontology (ABFO) has provided a scoring system which gives scores for gross features, tooth position and intradental features for evaluating the evidence collected from bite marks.

• While evaluating the bite mark firstly the cause of the mark has to be determined, since bite marks may be caused by nonhumans or humans.

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• Following two factors will help to differentiate bite marks caused by nonhuman from human.

1. Teeth size, shape and arrangement in the anterior portion of the arch:

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Human incisor teeth produce rectangular marks whereas canine teeth produce triangular marks in cross section.

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• Animal bites inflicted by dogs or cats puncture the skin and the cross sectional size of the tooth is small and circular.

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2. Size of the dental arch:

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• Width of the adult arches from canine to canine is 2.5-4 cm. Children's arches are smaller than the adults whereas dog's and cat's arches are smaller than children.

• METHODS OF ANALYSIS OF BITE MARKS:

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• Odontometric triangle method:

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• In this objective method a triangle is made on the tracing of bite marks and teeth models by marking three points, two on the outer most convex point of canines and one in the centre of the upper central incisors.
• Three angles of the triangles are measured and compared.

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• A clinico-anthropological study carried out by Manohar Singh et al by comparing bitemark width, bizygomatic and bigonial width concluded that from a given bitemark impression the facial dimensions of a person who is responsible for the mark can be determined

Comparison techniques:

• They use life size 1:1 photographs and models of teeth.

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• In assisted comparison method, specialized techniques such as microscopic methods, radiographs or experimental bite marks are used.

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• Comparison techniques can be classified as direct and indirect methods.

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Direct method:

• Model from the suspect can be directly placed over the photograph of the bite mark to demonstrate concordant points. Video tape can be used to show slippage of teeth producing distorted images and to study dynamics of the bite marks.

• Indirect method:
• Indirect method involve preparation of transparent overlay of occlusal or incisal surfaces of the teeth which are then placed over the marks on the photographs.
• Over lays may be produced by tracing the occlusal surface of teeth by placing cellulose acetate paper over the model, Xeroxing the model on the transparent sheet, use of reverse negatives which preserves the anatomic details, recording bite in a wax sheet or sprinkling radio-opaque powders into the teeth impression, then producing a radiograph.
• CT scan can be used to produce overlays of the dentition at varying depths.

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• This is considered to be an accurate method of overlay production.

Special methods in bite mark analysis:

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• Vectron: Vectron is used to measure distances between fixed points and angles.

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• Stereometric graphic analysis: This can be used to produce contour map of the suspect's dentition.

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• Experimental marks: Experimental bite marks may be produced on the pig skin, bakers dough or rubber for analysis.

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Result: In comparing a particular bite mark, it is important to respond affirmatively, negatively or stating that the evidence is insufficient for a firm conclusion.

Bite marks in inanimate objects:

• Bite marks found in a variety of inanimate objects such as wooden cabinets, pipe stems, mouth pieces of musical instruments and more commonly in the food stuffs, such as cheese, chocolate, apples, chewing gums etc have been reported.

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• Terminologies such as three dimensional bite, tentative bite, complete bite, sliding bite are used to describe bite marks in food.
• To overcome this confusion Webster classified them into three types.

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• Type I: Bites that are found in materials such as chocolate, which fracture readily with a limited depth of penetration. Bites of this type will record the most prominent incisal edges of the upper and lower anterior teeth upto a depth of 1-2 mm.

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• Type II: those where a good grip of the material is obtained by the teeth and then the bitten piece is removed by fracturing it from the main material
• eg., apple. This type of bite shows a record of the outline of labial aspect of upper and lower incisors and tooth scrape marks tend to record those elements of teeth which are most prominent anteriorly.
• Type III: Bites of this type are produced by biting through the material such as cheese.
• It has an advantage that it indicates relative positions of upper and lower incisors in centric occlusion from the extensive scrape marks.

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• Preservation:
• Storage of the food materials with bite mark can be done by placing them in air tight bags and then in refrigerator or by using preserving solutions (made up of equal parts of glacial acetic acid, formalin and alcohol).
• Long term preservation can be done by taking photographs and by preparing models.

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• The scientific basis of bite mark analysis is rooted in the premise of the individuality of the human dentition, the belief that no two humans have identical dentitions in regard to the size, shape, and alignment of the teeth.

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• Bitemark analysis is similar to fingerprint or DNA analyses, with one major exception. Fingerprint and DNA analyses can be expressed quantitatively as a numerical probability based on research database.

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CONCLUSIONS OF BITE MARK ANALYSIS

• Following comparison, any bite mark analysis has three likely outcomes. These conclusions are suggested along the lines of those given by Levine.

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Definite Biter

• There is reasonable medical certainty to indicate that the bite mark has been produced by the suspect’s dentition: There is absence of any unexplainable discrepancies.

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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.

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.

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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.

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THE PALATAL RUGAE IN IDENTIFICATION�[RUGOSCOPY]

Useful method in edentulous individuals

Rugae pattern – unique to an individual.

• 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.

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• Palatal rugae are ridges on the anterior part of the palatal mucosa on each side of the mid-palatine raphae, behind the incisive papilla.

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• These asymmetric and irregular ridges are well protected by the lips, cheek, tongue, buccal pad of fat and teeth in incidents of fire and high-impact trauma.

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Classification of Palatal rugae

Ly’sells Classification

• Primary Rugae (>5mm)
• Secondary Rugae (3-5mm)
• Fragmentary Rugae (2-3mm)

Thomas & Kotze Classification

1. Branched

2. unified

3. cross linked

4. Annular and

5. Papillary

Analysis of Rugae Patterns

Thomas & Vanwyk – Manually traced rugae patterns on to clear acetate & superimposed on photographs of plaster models

Limson & Julian – ‘RUG FP – ID Match’

- Computer software program – same principle as employed in finger print analysis.

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Rugae pattern

Lip Prints

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• The wrinkles and grooves visible on the lips have been named by Tsuchihashi as 'sulci labiorum rubrorum'.

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• The imprint produced by these grooves is termed 'lip print', the examination of which is referred to as 'cheiloscopy'.

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• These grooves are heritable and are supposed to be individualistic. Lip prints, therefore, can constitute material evidence left at a crime scene, much like fingerprints.

• Cheiloscopy [Examination of lip prints]
• Cheiloscopy is a forensic investigation technique that deals with identification of humans based on lips traces.

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• Lip prints have to be obtained within 24 hours of time of death to prevent erroneous data that would result from post mortem alterations of lip.

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• Lip print pattern depends on whether mouth is opened or closed.

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• In closed mouth position lip exhibits well defined grooves, where as in open position the groves are relatively ill defined and difficult to interpret

Classification of lip prints

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Lip prints were first classified by Santos in 1967 into two categories:

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Simple wrinkles

• • Straight line
• • Curved line
• • Angled line
• • Sine-shaped curve

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Compound wrinkles

• • Bifurcated
• • Trifurcated
• • Anomalous

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• Suzuki and Tsuchihashi (1970) later proposed a separate classification, dividing the pattern of grooves into six types

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• Type I - Clear-cut vertical grooves that run across the entire lip

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• Type I' - Similar to Type I, but do not cover the entire lip

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• Type II - Branched grooves

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• Type III- Intersected grooves

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• Type IV - Reticular grooves

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• Type V - Grooves that cannot be morphologically differentiated.

• A combination of these grooves may be found on any given set of lips.

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• To simplify recording, the lips are divided into quadrants similar to the dentition-a horizontal line dividing the upper and lower lip and a vertical line dividing right and left sides.

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• By noting the type of groove in each quadrant, the individual's lip print pattern may be recorded

• Lip prints are usually left at crime scenes and can provide a direct link to the suspect.

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• Traditionally, the use of lipsticks was essential to leave behind colored traces of lip prints.

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• In recent years, however, lipsticks have been developed that do not leave any visible trace after contact with surfaces such as glass, clothing, or cigarette butts.

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• Nevertheless, these lipstick marks are characterized by their permanence and produce 'persistent' lip prints that can be recovered days after being produced.

• Although invisible, Alvarez and associates have shown that these prints can be developed and visualized using agents such as aluminium powder and magnetic powder.

• It is also interesting to note that the use of lipsticks is not indispensable for leaving lip prints.

• Ball states that the vermilion border has minor salivary glands and the edges of the lips have sebaceous glands with sweat glands in between.

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• The secretions of oil and moisture from these enable development of 'latent' lip prints in most crime scenes, analogous to latent fingerprints, where close contact between the victim and culprit has occurred.

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Disadvantage of Lip Print Investigation:

• Major trauma to the lips can result in scarring.

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• Surgical treatment rendered to correct any abnormality also affects the size and shape of the lips, thereby altering the pattern and morphology of the grooves.

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• The prints produced may differ in appearance depending on the pressure applied and its direction.

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• Hence, lip prints caused by one individual may be mistakenly identified as those from another.

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Therefore, ball concludes that this sub-specialty of forensic odontology requires further study

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Tooth Prints (ameloglyphics)

• Are the pattern made by enamel rod ends on the crown surface of teeth.

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• Manjunath and coworkers analyzed them using acetate peel technique in 30 teeth and found that no two teeth were showing similar pattern.

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• Forensic value is questionable because the patterns are subject to change as tooth undergo regressive alterations and the direction of rods are different at different levels of the tooth.

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• Tooth prints were obtained at temperatures as high as 750^o C and up to 20 min of immersion of tooth in the 36.46% concentrated hydrochloric acid, hence, supporting the application of this technique in the case of burn or acid injury also.

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FUTURE & SCOPE OF FORENSIC ODONTOLOGY�

• Research
• Therapeutic Method For Identification
• Molecular Techniques
• Ameloglyphics For Person Identification
• Standardisation Of Classification, Collection Techniques
• Biochemical Methods Of Age Estimation Needs Further Research
• Awareness About Abuse
• Documentation

• CONCLUSION

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• The roles of any forensic scientist are to collect, preserve and interpret trace evidence, then to relay the results to the judicial authority in a form of a report.

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• Forensic Odontology is the forensic science that is concerned with dental evidence.

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• Dental practitioners should be aware of the forensic application of dentistry.

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• Dental records that are used to provide patients with optimal dental service could also be very beneficial to legal authorities during an identification process.

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• Therefore, all forms of dental treatments should be recorded and kept properly.

• Dental clinicians, as other healthcare workers, are at the forefront in detecting signs of violence appearing on their patients.

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• They should be aware of the criteria of abusive injuries, and the reporting mechanisms to ensure a correct response by the concerned authorities.

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• Though forensic odontology has achieved giant strides in recent times, various techniques utilized in forensic odontology are abided by limitations.

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• These limitations are to be kept in mind when answering queries in the court of law while prosecuting an accused, because an improper conclusion can alter and shatter the dreams and lives of alleged accused too.

References

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• Shafer’s textbook of oral pathology - 8th edn
• Textbook of oral pathology – Neville
• Lip Prints. T.N. Uma Maheshwari
• Advanced Technologies An Aid In Forensic Odontology : an update ; International Journal of Advanced Research (2015), Volume 3, Issue 10
• Ameloglyphics: A possible forensic tool for person identification following high temperature and acid exposure ; Manjushree Juneja et al ; 2016
• Teeth in Fire - Morphologic and Radiographic Alterations: An In Vitro Study ;Priyanka S et al; 2015
• Gender determination using barr bodies from teeth exposed to high temperatures; Vikram Simha Reddy et al; 2017
• Singh K, Anandani C, Bhullar RK, Agrawal A, Chaudhary H, et al. (2012) Teeth and their Secrets - Forensic Dentistry. J Forensic Res 3:141. doi: 10.4172/2157-7145.1000141

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Thank you….