Forensic Odontology

RINEE KHANNA

FORENSIC ODONTOLOGY

Presented By:Rinee Khanna

RINEE KHANNA

Overview

FORENSIC DENTISTRY

Human identification

Bite mark analysis

Comparative identification

Postmortem dental

profiling

Dental recordsForensic

anthropology

AgeRace Sex

Factors Of Individualizat

ion

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Definition

‘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.’ -FDI

Primarily deals with identification, based on recognition of unique features present in an individual’s dental structures.

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Forensic odontologists delve into:

Identifying unknown human remains. Victim’s identification in mass disaster. Electing the picture of life style and diet of skeletal remains at forensic and archaeological sites. Assessing sex of skeletal remains. Age estimation of both living and deceased. Analysis and identification of bite marks at crime scenes.

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Why Teeth?

Every human body ages in a similar manner, the teeth also follow a semi-standardized pattern. These quantitative measurements help establish relative age of person.Each human has an individual set of teeth which can be traced back to established dental records to find missing individuals.Teeth is made of enamel (hardest tissue of the body) so it can withstand trauma (decomposition, heat degradation, water immersion, and desiccation) better than other tissues in body. Teeth are a source of DNA: dental pulp or a crushed tooth can provide nuclear or mitochondrial DNA that to help identify a person.

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History of Forensic Odontology

66AD – First body identified using teeth Lollia Paulina

Revolutionary War Paul Revere was the first forensic dentist in the United States because he identified fallen revolutionary soldiers.

1849 – Mass deaths at Vienna Opera House Fire Dental evidence is first admitted into court system in US

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PERSONAL IDENTIFICATION

Identification is the establishment of a person’s individuality Required for legal and humanitarian reasons Help in settlement of property ,facilitate remarriage of a surviving spouse and allow cremation or burial of the body ,according to relevant religious and cultural customsTRADITIONAL METHODS included:

Visually recognizing body Personal property such as clothing ,jewellery etc

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BASIS FOR DENTAL IDENTIFICATION

Human dentition is never same in any two individuals The morphology and arrangement of teeth vary from person to person Teeth are relatively resistant to environmental insults after death.

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DENTAL IDENTIFICATION PROCEDURES

TWO FORMS:1. Comparative 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.

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COMPARITIVE DENTAL IDENTIFICATION

INCLUDES FOUR STEPSStep 1:oral autopsy Step 2:obtaining dental records Step 3:comparing post mortem and anti-mortem dental dataStep 4:writtin a report and drawing conclusion

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ORAL AUTOPSY

Also known as necropsy or post mortem 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

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Oral examination is an essential part of post-mortem procedures A forensic dentist who conduct oral autopsy should have adequate knowledge about common post-mortem findings such as rigor mortis ,liver mortis ,decomposition and post-mortem artifacts. Rigor mortis may render the jaw and the use of mouth gags or intra oral myotomy is essential for jaw separation.

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Teeth - brittle in burned cases - reinforced with cyano acrylate cements, polyvinyl acetate or clear acrylic spray prior to examination Access for radiology in incinerated bodies - 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.

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OBTAINING DENTAL RECORDS From treating dentist, specialist, 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 ante mortem form’ which is color coded in yellow

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COMPARNG POST-MORTEM &ANTE-MORTEM DENTAL RECORDS

Features compared include tooth morphology and associated 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 characteristics Comparison should take in to account quality rather than quantity

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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 Insufficient information: available anti & post-mortem data are insufficient Excludes identification: anti & post mortem data are clearly inconsistent

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IDENTIFICATION IN DISASTERS

Involves comparing hundreds or thousands ,of ante & post mortem data Human remains in such events may be highly fragmented , only part of body may be recovered ;the bodies may be incinerated or commingled i.e. Parts of two bodies may be mixed.

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DENTAL SECTION

FORENSIC DENTIST ARE USUALLY PART OF A TEAM OF IDENTIFICATION SPECIALIST THREE SUB SECTIONS1.POST MORTEM UNITS 2.ANTE –MORTEM UNITS 3.DENTAL COMPARISON IDENTIFICATION UNITS

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POST-MORTEM 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 mortuary of post-mortem unit A portable dental radiography 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 convenience of examination

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AANTE-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

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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

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IDENTIFICATION FROM DENTAL DNA

Teeth are excellent source of DNA since it can resist extreme condition PCR allows amplification of even high degraded DNA. Major advantage is that if decedent's ante mortem sample (hair from hair brush, epithelial cells from tooth brush or biopsy)is unavailable ,the DNA pattern may be compared to a parent or to a sibling

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EXTRACTION OF DENTAL DNA Pulpal tissue best source of dental DNA Cryogenic grinding for extracting DNA(cooling the whole tooth to extremely low temperature and then mechanically 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 tissue debris.

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TYPES OF DNA TWO TYPES OF DNA 1)GENOMIC OR NUCKEAR DNA 2)MITOCHONDRIAL DNA (mtDNA) Each cell has a high copy mtDNA ,also exclusively inherited from mother ; no contribution from father Thus identical mtDNA is observed in siblings, their mother and many maternal relatives

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THE PALATAL RUGAE IN IDENTIFICATION

Useful in edentulous persons Rugae 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 recovered from the decedent’s residence, or plaster model from dental office

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CLASSIFICATION OF PALATAL RUGAE

Lysell measured rugae in a straight 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 , cross linked, annular, & papillary.

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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 software program, ’rugfp-id match’(same principle of finger printing)

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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 focused search for ante-mortem records

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IDENTIFY ETHNIC ORIGIN FROM THE TEETH Human races have been divided in to three races Caucasoid, mongaloid and negroid It is possible today to identify an individual’s ethnic origin based purely on one’s dentition

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GENETIC AND ENVIRONMENTAL INFLUENCE ON TEETH Dental features have complex mode of inheritance and are combination of heredity 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

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NON METRIC DENTAL FEATURES

CROWN FEATUREShoveling, double shoveling, carebelli’s feature, three cuspid upper 2nd molar, cusp 5, cusp 6,cusp 7, wiggling, five -cuspid lower second molar, lower molar groove pattern, interruption groove, enamel extension, odontome, lateral incisor variation, distal accessory ridge, premolar accessory ridge, premolar accessory marginal tubercle, premolar lingual cusp, mesial marginal tubercle of upper molar, parastyle, protostylid

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ROOT FEATURES: 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 uncommon e.g.: south-asian’s exhibit 4 cusped lower second molar but features like wiggling ,shoveling, y groove pattern tomes pattern

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SEX DIFFERENTIATIONSECOND STEPCAN 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

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Dental Age Estimation

Final step in dental profiling Estimation methods1). Age estimation in prenatal, neonatal and early post natal child-by use of histological 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)

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2.Age estimation in children and adolescents-two events may be used eruption and tooth calcification-various methodsa). 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 divided into 8 stages(A-H). Each tooth assigned 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.

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Pictorial representation of tooth development allows assessment of age

by comparing the charts to radiographs.

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 adultschallenging when compared to young age groups as numerous endogenous and exogenous factors, 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 apposition at the root apex(C).Root resorption 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)RINEE KHANNA

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 translucencyRINEE KHANNA

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C).Age Estimation from Incremental Lines Of Cementum

From acellular cementum incremental lines Made us of mineralized unstained cross-sections of teethD).Radiographic Method: Used pulp size measurement of six teeth5 2 1 1 2 5 4 2 1 1 2 4Age = 129.8-316.4(M)-66.8(W-L)

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The measurement include several length and width ratios such as:pulp-root length Ppulp-tooth length Rpulp-root width at CEJ Apulp-root width at mid-root level Cpulp-root width at mid-point between level C and A Bmean value of all ratio including excluding T Mmean value of width ratios B and C Wmean value of length ratio p and R L Age = 129.8-316.4(M)-66.8(W-L)

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Amino acid racemization

Suggested a relationship between dentinal age and extent of aspartic acid racemization in dentin. Aspartic acid undergo rapid rate of racemization and get spontaneously converted from L-Aspartic acid to D-Aspartic acid with increasing age. Comparing D-L ratio age can be estimated.

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Cranio-facial estimators of age

Cranial suture and also mandible provides certain characteristic for elicitation of ageSuture Endocranial initiation Ectocranial terminationSagittal 21 35Sphenoparietal 30 65Coronal 25 39Squamosal 37 80Sphenotemporal 30 68Lambdoid 26 41Mastooccipetal 26 72Spheno-frontal 24 35

INFANCY ADULT OLD AGE

BODY shallow Thick & long shallow

RAMUS Forms an obtuse angle with the body

Forms an approximate right angle

Obtuse angle

MENATAL FORAMEN

Located near lower margin of the body

Midway between upper and lower margin

Near alveolar margin

CONDYLE Occupies a lower level to the coronoid process

Elongated and projects above the coronoid

Neck is bentbackwards

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Cranial measurement (in mm) useful in sexing

CRANIAL VARIABLES M FCranial base length 112.5 103Mastoid height 12.5 9.6Mastoid width 24 19Total face height 127 114Bizygomatic breadth 129 122Basion-nasion length 102 96Cranial length 188 179Nasal height 54 50Maximum frontal width 120 115.5

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Cranial measurement (in mm) useful in sexing

MANDIBLE VARIABLES Male FemaleBicondylar breadth 117 111Bigonial breadth 100 91.5Minimum ramus breadth 31 28.5Gonion-gnathion breadth 77 73Total mandibular length 111 108

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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.

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Classification of bite marks

1.Cameron and Sims ClassificationAgentsHumansAnimalsMaterialsskin, body tissuefood stuffother materials2.Mac Donald’s classificationsTooth pressure markTongue pressure markTooth scrape mark

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3. Webster’s classificationType I- The food item fractures readily with limited depth of tooth penetration (e.g. Hard chocolate).Type II- Fracture of fragment of food item with considerable penetration of teeth (e.g. Bite marks in apple and other firm fruits).Type III- Complete or near complete penetration of food with slide marks (e.g. Cheese, banana).

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Bite mark appearance

Type of injury Identifying The Injury As a Bite Marka). Gross features: Circular or elliptical with central area of ecchymosis. b). Class features: Incisor rectangular Canines triangular or rectangular Premolars and molars spherical or point shapedc). Individual features: Class features intern have characteristics such as fractures rotation etc. Site of Bite MarksFemales on breast, legs( inner part of thigh)-sexual assaultMale children genitals-child abuseAdult Males finger, arms and shoulders-fight

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Bite mark investigation

Preliminary questions Bite mark evidence collection from the victimsif criminal in nature is reported to law enforcement agenciesSteps:1.Visual examination2.Photography Orientation photographsclose-up photographs3.Saliva swab: WBC and sloughed epithelial cells, potential source of DNA4.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

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Bite mark analysis and comparison

Jaw movement Flexibility of bitten tissue Individual features of bite marks Metric analysis Computer software program

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BITE MARKS ANALYSIS: USING 3D SCAN SYSTEM

The overlays are compared with the photograph of the bite marks.

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Conclusion Of Bite Mark Analysis

Positive identification Possible identification Excludes identification

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Investigating Animal Bites

Characteristics of some vertebrate dentitionfish conical, homodont, heterodont or polyphydontReptiles homodont conical or only tricuspid teethVenomous snake single row, palatal to this are two poison fangs containing canal or groove for venom releaseNon-Venomous two rows of maxillary teethMammals heterodont dentition, diphyodont also have accessional teeth( permanent molar emerge posterior to deciduous teeth)

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Lip Prints

Examination of lip print-cheiloscopy 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 wrinklesstraight line curved lineangled linesine shaped curve b) compound wrinklesBifurcated trifurcatedanomalous II)type 1- clear cut vertical grooves that run across the entire liptype 1’-similar to type 1 but not cover the entirelytype 2- branched groovestype 3- intercepted groovestype4- reticular groovestype 5- grooves that can not be morphologically differentiated Invisible prints can be lifted using materials such as aluminum powder, magnetic powderDISADVATAGE1. Trauma, pathosis, surgical treatment can affect the size and shape of the lip2. The zone of transition close to vermillion border is extremely mobile so prints produced may differ depending on pressure applied and its direction

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Various lip print patterns Lip print patterns demonstrating inter- individual variation

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