Medico-legal Investigation Skeletalization &Forensic Odontology

Medico-legal Medico-legal InvestigationInvestigation

Skeletalization &Forensic Skeletalization &Forensic OdontologyOdontology

Skeletalization

• TheThe environment is more environment is more important important than the than the timetime in this in this process.process.

• 12-18 months:12-18 months: bone and tendon tagsbone and tendon tags• After 3 yrs: After 3 yrs: bare bonebare bone..• In In temperate zonestemperate zones the bones will the bones will remain remain solid & heavy with the solid & heavy with the preservation of preservation of bone marrow bone marrow in long in long bones for a number of years.bones for a number of years.

• After 40-50 years After 40-50 years ::– Surface of the bone becomes dry & brittleSurface of the bone becomes dry & brittle– Marrow cavity will be emptyMarrow cavity will be empty..

The individual was recovered in a home The individual was recovered in a home with rats. Post-mortem bite marks are with rats. Post-mortem bite marks are yellow, bloodless defects with scalloped yellow, bloodless defects with scalloped edges.edges.

Post-mortem Gnaw Marks Post-mortem Gnaw Marks on the Boneon the Bone

Post-mortem vulture activity on a woman Post-mortem vulture activity on a woman discovered in a wooded area. The tendon is discovered in a wooded area. The tendon is visible through the hole while much of the visible through the hole while much of the muscle is absent. The yellow discoloration muscle is absent. The yellow discoloration around the hole is consistent with beak marksaround the hole is consistent with beak marks

The skeleton is that of an adult male who The skeleton is that of an adult male who was missing 1.5 months during late fall in was missing 1.5 months during late fall in the southeastern US. He was found in a the southeastern US. He was found in a wooded area. Gnaw marks are evident on wooded area. Gnaw marks are evident on several ribs.several ribs.

Forensic OdontologyForensic OdontologyAn Introduction to Forensic DentistryAn Introduction to Forensic Dentistry

Forensic OdontologyForensic Odontology

Hardest part of body attached to jaws. Hardest part of body attached to jaws. Teeth serves to help digest food, act Teeth serves to help digest food, act as a defense mechanism, etc. as a defense mechanism, etc.

TeethTeeth

Teeth BasicsTeeth Basics

• Tooth consists ofTooth consists of– RootRoot– Root canalRoot canal– DentinDentin– EnamelEnamel

Types of teeth. Types of teeth. Left to right: Incisor, Canine, Left to right: Incisor, Canine, Premolar, molar.Premolar, molar.


• Human Dentition and Dental AnatomyHuman Dentition and Dental Anatomy– Enamel is the hardest substance in the Enamel is the hardest substance in the human bodyhuman body

– Full compliment of adult dentition of Full compliment of adult dentition of 32 teeth32 teeth

– Each tooth presents 5 surfaces in a Each tooth presents 5 surfaces in a visual examination for a total of 160 visual examination for a total of 160 surfacessurfaces

– Arranged in 2 Dental Sets called Arranged in 2 Dental Sets called ““archesarches””• One Upper Arch = Maxillary JawOne Upper Arch = Maxillary Jaw• One Lower Arch = Mandibular JawOne Lower Arch = Mandibular Jaw

OdontologyOdontology



• Human Dentition and Dental Human Dentition and Dental AnatomyAnatomy– Dental Arches are SymmetricalDental Arches are Symmetrical– Each Quadrant contains the same Each Quadrant contains the same ““number and typenumber and type”” of teeth of teeth

ChildhoodChildhoodChildhoodChildhood AdulthoodAdulthoodAdulthoodAdulthood

Teeth through the yearsTeeth through the years

• Primary teeth sprout from milk Primary teeth sprout from milk buds and are temporary. Once they buds and are temporary. Once they fall out, permanent teeth as seen fall out, permanent teeth as seen on the other side appear. on the other side appear.

Permanent adult teeth come in when Permanent adult teeth come in when primary teeth fall out; they are primary teeth fall out; they are permanent because they establish permanent because they establish roots inside the gums. Third molars roots inside the gums. Third molars come in around the mid teenage years.come in around the mid teenage years.

Forensic OdontologyForensic Odontology• The Human has the The Human has the following:following:– 2 Incisors = sharp, 2 Incisors = sharp, flat, wide teeth for flat, wide teeth for cuttingcutting

– Cuspid = tearing, Cuspid = tearing, ripping and grippingripping and gripping

– 2 Premolar = 2 cusps 2 Premolar = 2 cusps for biting and for biting and crushingcrushing

– 3 Molar = 3-5 cusps 3 Molar = 3-5 cusps (wide biting area)(wide biting area)

– Third molar = Wisdom Third molar = Wisdom (last tooth in arch)(last tooth in arch)


• Key to Dental Anatomy Key to Dental Anatomy is: is: – OrientationOrientation– Tooth SurfaceTooth Surface– Landmarks and Landmarks and StructuresStructures• M = mesialM = mesial• O = occlusalO = occlusal• D = distalD = distal• L = lingualL = lingual• B = buccalB = buccal

distal ←, mesial →, coronal ↑, apical ↓.


Individual Individual CharacteristicsCharacteristics

Size of toothSize of toothShape of toothShape of toothShape of rootShape of rootPlacement of toothPlacement of toothQuantity of teethQuantity of teethCombinations of Combinations of dental work done:dental work done: CrownsCrowns ExtractionsExtractions BridgeBridge FillingsFillings Root canals Root canals

Various dental work

Analyzing TeethAnalyzing Teeth

• The Universal SystemThe Universal System1.1. Teeth are given a Teeth are given a

specific number. specific number. (Primary teeth are (Primary teeth are given specific capital given specific capital letter)letter)

2.2. Any dental work done Any dental work done on surface is notedon surface is noted

3.3. Sheets kept on dental Sheets kept on dental file forever. When file forever. When person is missing, person is missing, files are transferred files are transferred to the missing to the missing person’s officeperson’s office

Various Teeth FoundVarious Teeth Found

Why Teeth?Why Teeth?

Every human body ages in a similar mannerEvery human body ages in a similar manner, the teeth also , the teeth also follow a semi-standardized pattern. These quantitative follow a semi-standardized pattern. These quantitative measurements help establish relative age of person.measurements help establish relative age of person.

Each human has an individual set of teethEach human has an individual set of teeth which can be traced which can be traced back to established dental records to find missing back to established dental records to find missing individuals.individuals.

Teeth are made of enamel (hardest tissue of the body) so they Teeth are made of enamel (hardest tissue of the body) so they can can withstand withstand traumatrauma (decomposition, heat degradation, water (decomposition, heat degradation, water immersion, and desiccation) better than other tissues in body. immersion, and desiccation) better than other tissues in body.

Teeth are a Teeth are a source of DNAsource of DNA: dental pulp or a crushed tooth can : dental pulp or a crushed tooth can provide nuclear or mitochondrial DNA to help identify a provide nuclear or mitochondrial DNA to help identify a person.person.

Dental X-raysDental X-rays

Forensic OdontologyForensic Odontology– Scope of FO is the Scope of FO is the following:following:• Identification of unknown Identification of unknown decedents by analyzing decedents by analyzing dentition (teeth), jaw dentition (teeth), jaw structure, craniofacial structure, craniofacial bones, maxillofacial bonesbones, maxillofacial bones

• Bite mark investigationBite mark investigation• Examination of oral-facial Examination of oral-facial trauma involving trauma involving person/child abuseperson/child abuse

• Medico-legal jurisprudence Medico-legal jurisprudence and expert witness testimonyand expert witness testimony

Who practices Forensic Odontology Who practices Forensic Odontology and what do they do?and what do they do?

Forensic Forensic Odontologists Odontologists Must have DDS degreeMust have DDS degree Should have specialized Should have specialized training in the field training in the field through lectures (not through lectures (not required)required)

Forensic dentists Forensic dentists help:help: Identify human remains Identify human remains (individual and mass) (individual and mass)

Analyze bite marksAnalyze bite marks Bite marks are compared Bite marks are compared to known teeth molds to to known teeth molds to find origin of bite find origin of bite injuries injuries

Estimate age of the Estimate age of the victim and perpetrator victim and perpetrator

Trace dental Trace dental malpracticemalpractice

Top: Forensic Odontologist analyzing animal teeth for comparison.

Side: Seal for American Board of Forensic Odontology.

HistoryHistory

• The earliest known identification The earliest known identification from teeth is in 1775 by Paul from teeth is in 1775 by Paul Revere.Revere.

• Paul Revere made a silver bridge Paul Revere made a silver bridge for one man. The man was killed for one man. The man was killed in the Revolutionary War.in the Revolutionary War.

• Body was in a mass grave and Body was in a mass grave and identified by his silver dental identified by his silver dental work and hippo tusk.work and hippo tusk.

History of Forensic History of Forensic OdontologyOdontology

• 66AD – First body identified 66AD – First body identified using teethusing teeth– Lollia PaulinaLollia Paulina

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

Organizations of Organizations of Forensic OdontologyForensic Odontology

• Bureau of Legal Dentistry Bureau of Legal Dentistry (BOLD)(BOLD)

• American Board of Forensic American Board of Forensic Odontology (ABFO)Odontology (ABFO)

• International Organization International Organization for Forensic Odonto-for Forensic Odonto-Stomatology (IOFOS)Stomatology (IOFOS)

Forensic OdontologyForensic Odontology• Postmortem dental Postmortem dental

examination should examination should include examination include examination of:of:– Missing, unerupted Missing, unerupted or extracted teethor extracted teeth

– Restorations and Restorations and prosthesisprosthesis

– Decay and broken Decay and broken teethteeth

– Malposition, Malposition, overlapping, overlapping, crowding and spacingcrowding and spacing

• IdentifyingIdentifying

factors suchfactors such

as cavities,as cavities,

tooth pattern,tooth pattern,

and generaland general

dental healthdental health

neglectneglect


• Peculiar shapes of teethPeculiar shapes of teeth• Root canal on x-rayRoot canal on x-ray• Bone pattern on x-rayBone pattern on x-ray• Bite patternsBite patterns


Impressions from teeth found on skin Impressions from teeth found on skin or items left at a scene. Usually or items left at a scene. Usually outline teeth placement.outline teeth placement.

Bite MarksBite Marks


• Forensic Forensic Odontology may Odontology may include the include the study of bite study of bite mark patterns mark patterns on the victim.on the victim.– Digital overlay Digital overlay is used to make is used to make a comparison.a comparison.

Ted BundyTed Bundy

List of Skull Bones List of Skull Bones for You to Knowfor You to Know

• Frontal Frontal • ParietalParietal• Occipital Occipital • TemporalTemporal• Zygomatic (and arch)Zygomatic (and arch)• OrbitOrbit• MaxillaMaxilla• MandibleMandible

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Medico-legal Investigation Skeletalization &Forensic Odontology