Bitemarks

New technologies about Bitemarks- A potent tool in forensic dentistry

1. BITEMARKS

2. contents Introduction History Classification Collection DNA sampling References Conclusion

3. INTRODUCTION Forensic Odontology is the application of dentistry in legal proceedings deriving from any evidence that pertains to teeth. OR Area of dentistry concerned with the correct management, examination , evaluation & presentation of dental evidence in civil/criminal legal proceedings in the interest of justice ( Neville)

4. A Source Of Identification 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.

5. Teeth is made of enamel (hardest tissue of the body) - 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.

6. 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

7. Salim witch trials-1692- first reported incidence of bitemark identification Doyle v/s State-first bitemark to be reported as an american judiciary opinion( 1954)- Cheese thief

8. Frye- Daubert v/s Merell Dows Techniques-tested & testable Peer review and publication of results-admit evidence in court Standards-evaluation of scientific methods & error rates Acceptance of scientific principles-general acceptance & scientific validity Federal rule of evidence-702-705

9. TEETH BASICS Approximately 32 teeth in adult mouth Four types of teeth: Molars Premolars Canine Incisors Teeth differ in: Size Shape Root type

10. BITEMARKS Mac donald - a mark caused by the teeth either alone or in combination with other mouth parts Recorded, documented and described -size, location and severity Attack injuries (present on the victim) defensive wounds ( present on the suspect)

11. Severity: force – medium severity significant -original injury was inflicted -anatomical location bitten - time elapsed between infliction and presentation

12. CLASSIFCATION Cameron & Sims- type of agent producing & material exhibiting Agents-Human & Animal Materials skin, body tissue Foodstuff Other materials

13. Mac Donalds - etiologic Macdonald DG. Bite Mark Recognition And Interpretation . J Forensic Sci Soc 1974; 14(3): 229 Tooth pressure marks -tissue-direct application of pressure by teeth. Eg - incisal / occlusal surfaces Tongue pressure marks- sufficient amount of tissue in mouth-presses against rigid areas-lingual surface of teeth & palatal rugae -marks left on skin- Suckling Tooth scrape marks- scraping of teeth across bitten material. caused by ant teeth, scratches & superficial abrasion

14. Outlines of the same set of teeth. The different perimeter shapes depend on how far the teeth are pressed into the test substrate.

15. Webster’s –foodstuff- theft/robbery Type 1- food item fractures readily-limited tooth penetration eg - hard chocolate Type 2- considerable food penetration eg - apple & other firm fruits Type 3- complete penetration of food item with slide marks- eg cheese

16. Type of injury Abrasion Ecchymosis Laceration Petechial hemorrhage Incision Artefactorial - proximate stab & bullet wound-distort pattern by separation of anatomic cleavage lines- langer’s lines

17. Identifying injury as a bite mark Gross features: -circular/elliptical mark-upper & lower arch -central area ecchymosis - sucking action-distinct Class features: differentiate b/n tooth type -incisors-rectangular -canines-triangular -premolars + molars – spherical/point shaped - Depends on attrition

18. Bicuspid-figure of eight Greatest dimension of adult arch-4 cm Single arch-crescent shaped Class II malocclusion-palatal surface of ant teeth-shield like pattern TMD midline shift, inability to open mouth-muscle force, bite pattern, tongue thrusting

19. Individual features: fractures/rotations/spacing Site of bitemark : Pretty & Sweet -females-sexual assualt -breast & legs -males- fights- arms & shoulders

20. Diff b/n human & carnivore bite Features Human Carnivore Arch size & shape Broad, u-shaped, circular Narrow ant aspect, V-shaped/elongated Teeth Broad central, narrow lateral, blunt Narrow central, broad lateral, long & sharp canines Injury pattern Bruising, laceration Severe laceration, avulsion, greater skin damage Site Breast, abdomen, back, shoulder Extremities, exposed skin

21. Collection of bitemarks Photography(bite victim) With and without the ABFO No. 2 scale In colour and black and white On and off camera flash (oblique flashes -the three-dimensional nature An overall body shot showing the location of the injury

22. Close-ups that can easily be scaled 1:1 UV photography if the injury is fading If the bite is on a moveable location-several body shots-effect of movement Camera at 90° (perpendicular) to the injury Regular 24 hour intervals on both the deceased and living victim

23. Collection of items Dental impression of the victim − self-biting /bite injuries of suspect DNA swabbing of the injury site –double swab – the first moistened with distilled water and the second dry Impression of the bite injury –significant degree of three-dimensional detail is present Skin removal –permits trans-illumination of bitemark , Flawed- skin contraction

24. Collection of evidence from the bite suspect Overall facial shot Close-up photograph of the teeth in normal occlusion and biting edge to edge Photograph of the individual opening as wide as possible Lateral view -dental charting - condition of each teeth

25. High quality impressions - upper + lower arches Prosthesis-with & without poly-vinyl siloxane (PVS) impression material+ plastic stock trays-multiple times Alginate-pour-1−2 hours- contraction sheet of softened wax- occlusal record

26. WAX BITE Impression materials & trays Cast with & without prosthesis

27. Visual index of the bitemark severity and significance scale

28. Analysis of bitemark injuries Accidental or non-accidental American board of forensic odontology (ABFO) Exclusion – the injury is not a bitemark . Possible bitemark – injury showing a pattern that may or may not be caused by teeth, could be caused by other factors but biting cannot be ruled out.

29. Probable bitemark – the pattern strongly suggests or supports origin from teeth but could conceivably be caused by something else. Definite bitemark – there is no reasonable doubt that teeth created the pattern.

30. Conclusions –bite mark analysis Definite biter: medical certainity + bitemark dimension/pattern similar to suspect teeth Probable biter: degree of specificity with suspect teeth-> matching points Possible biter: consistency- non specific match Not the biter: not at all consistent Exclusion: not a bitemark

31. Pattern analysis in bitemark evidence Biometric analysis Transparent overlay-dental casts of suspects-biting edges- reproduced on transparent sheets Overlays placed over the scaled 1:1 photographs of the bite injuries & compared

32. Sample Analysis Bitemark : Upper Jaw Distance Suspect ; Upper Jaw Distance Cuspid to cuspid Cuspid to cuspid 38mm 42mm   Bitemark: Distance Suspect: : Distance Tooth 6 to Tooth 10 Tooth 6 to Tooth 10   44.25mm 39.65mm Angle: + 14.5 Degrees Angle: + 12.52 Degrees

33. Methods of overlay production Computer-based radiographic Xerographic Hand-traced(acetate sheets and marker pen)

34. 3-d analysis Have been developed to overcome some of these problems Theoretically : Correct for distortion Generate the overlay objectively Carry out the comparison objectively Reproduce the overlay

35. A typical digitized dental model imported into Rapidform editing software bite mark image generated by the dental casts. Digitized 3D dental model with intersecting plane and captured tooth contour.

36. A. Van Der Velden . Bite Mark Analysis And Comparison Using Image Perception Technology J Forensic Odontostomatol 2006;24:14-7 New method of analysing bite marks- Image Perception Technology Artificially colour areas with equal intensity values 2-D image as a pseudo-3-d surface object.

37. Corresponding incisal detail in bite mark photograph and compound overlay Pseudo 3-D image- visible bite mark detail Image artificially coloured with image perception technology software Original photograph

38. Bitemarks and DNA Wet swab rehydrates the salivary constituents, releasing more epithelial cells from the dried deposit DNA typing of bacteria & its recovery / SEM analysis of bite wounds

39. Presence of nucleic acid-degrading enzymes (nucleases) saliva can rapidly degrade DNA, (living victim) skin temperature accelerate Sweet’s double swab technique-rather than just relying upon pure ‘salivary’ DNA Pretty IA, Sweet D. Anatomical location of bitemarks and associated findings in 101 cases from the United States . J Forensic Sci 2000; 45(4): 812−814

40. Genotypic identification of oral streptococci one year later and found that their genotypes-same a. Kit- including two swabs (for skin only, buccal suspect swabs require only one), gloves, card drying rack, evidence stickers, sealable plastic bag, documentation and evidence envelope b. dried prior to placement in sealed evidence bag. Drying is a crucial stage and can take up to 30 minutes.

41. techniques DNA typing DNA probe RFLP analysis (restriction fragment length polymorphism) FISH- Fluorescence in situ hybribization

42. Bites on perishable items, nonhuman substrates Apples, cannabis resin, sandwiches, bank books, pencils,pacifiers , Styrofoam cups , envelopes Positive impressions of the bite mark taken with plaster from the negative Negative impressions of the bite mark taken from the apple

43. limitations Reliable scientific tool or not 1. Numerous methods of fabrication 2. Relies on manual fabrication 3. Subjective element in fabrication 4. Subjective element in comparison 5. Distortion 6. Loss of data, contamination

44. conclusion Case no., date of examination, name of examiner Orientation & location of mark Type of injury Colour , size, shape Contour, texture, elasticity of bite Diff b/n upper & lower arch/ individual teeth

45. references Shafer’s –textbook of oral pathology Lessig R*, Wenzel V, Weber M . Bite mark analysis in forensic routine case work . EXCLI Journal 2006;5:93 Iain A Pretty. Forensic dentistry & bitemarks . Dental update 2008.

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