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Forensic odontology

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Forensic odontology

  1. 1. • 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
  2. 2. • 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
  3. 3. • 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
  4. 4. 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
  5. 5. 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
  6. 6. 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
  7. 7. • 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
  8. 8. • 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
  9. 9. 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
  10. 10. 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
  11. 11. 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
  12. 12. 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
  13. 13. • 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
  14. 14. • 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
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. 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
  19. 19. 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
  20. 20. 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 • TEETH AND JAW SPECIMEN MAY BE REMOVED FROM A BODY FOR THE CONVEININCE OF EXAMINATION
  21. 21. 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
  22. 22. 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
  23. 23. 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
  24. 24. 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
  25. 25. 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
  26. 26. 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
  27. 27. 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
  28. 28. 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)
  29. 29. 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
  30. 30. 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
  31. 31. 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
  32. 32. 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
  33. 33. 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
  34. 34. 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
  35. 35. 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)
  36. 36. 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.
  37. 37. 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). Method: 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)
  38. 38. 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
  39. 39. Cranio-facial estimators of age • Cranial suture and also mandible provides certain characteristic for elicitation of age Surture Endocranial initiation Ectocranial termination Sagittal 21 35 Sphenoparietal 30 65 Coronal 25 39 Squamosal 37 80 Sphenotemporal 30 68 Lambdoid 26 41 Mastooccipetal 26 72 Sphenofrontal 24 35
  40. 40. 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 bent backwards
  41. 41. • 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
  42. 42. • 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
  43. 43. 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.
  44. 44. 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
  45. 45. 3. Webster’s classification Type I Type II Type III
  46. 46. 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
  47. 47. 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
  48. 48. Bite mark analysis and comparison • Jaw movement • Flexibility of bitten tissue • Individual features of bite marks • Metric analysis • Computer software program
  49. 49. Conclusion Of Bite Mark Analysis • Positive identification • Possible identification • Excludes identification
  50. 50. 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
  51. 51. Thank You!

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