BITEMARKS

CONTENTS

Introduction History Classification Collection DNA sampling References Conclusion

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)

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.

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.

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

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

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

TEETH BASICS

Approximately 32 teeth in adult mouth

Four types of teeth: Molars Premolars Canine Incisors

Teeth differ in: Size Shape Root type

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)

Severity: force – medium severity

significant

-original injury was inflicted

-anatomical location bitten

- time elapsed between infliction and

presentation

CLASSIFCATION

Cameron & Sims- type of agent producing & material exhibiting

Agents-Human & Animal Materials skin, body tissue Foodstuff Other materials

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

Outlines of the same set of teeth. The different perimeter shapes

depend on how far the teeth are pressed into the test substrate.

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

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

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

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

Individual features: fractures/rotations/spacing

Site of bitemark: Pretty & Sweet-females-sexual assualt-breast & legs-males- fights- arms & shoulders

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

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

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

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

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

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

WAX BITE

Impression materials & traysCast with & without prosthesis

Visual index of the

bitemark severity and significance

scale

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.

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.

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

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

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

METHODS OF OVERLAY PRODUCTION Computer-based radiographic Xerographic Hand-traced(acetate sheets and

marker pen)

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

A typical digitized dental model imported

into Rapidform editing software

bite mark image generatedby the dental casts.

Digitized 3D dental model with intersectingplane and captured tooth contour.

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.

Corresponding incisal detail in bite markphotograph and compound overlay

Pseudo 3-D image- visible bite mark detail

Image artificially coloured with image perception technology

software

Original photograph

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

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

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 evidenceenvelopeb. dried prior to placement in sealed evidence bag. Drying is a crucial stage and can take up to 30 minutes.

TECHNIQUES

DNA typing

DNA probe

RFLP analysis (restriction fragment

length polymorphism)

FISH- Fluorescence in situ hybribization

BITES ON PERISHABLE ITEMS, NONHUMANSUBSTRATES

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

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

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

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.

Thank you