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ODONTOLOGY
Forensic Dentistry
Definition of Odontology
• “The application of the arts & sciences of dentistry to the legal system.”
– Identification of individuals– Bite mark analysis– Analysis of personal injury to head/neck– Dental malpractice
Dentition Descriptions
• Primary Dentition– “Baby” teeth; 20 total– Develop in utero around 16 weeks– Eruptions begins around 6 months
• Secondary Dentition– “Permanent” Teeth– 32 teeth total
Teeth Type• Incisors
• 8 total; used to cut food
• Cuspids• 4 total; used to tear food.• “Eye teeth” or “Canines”
• Bicuspids• 8 total; used to crush food.• “Pre-molars”; primary larger than secondary.
• Molars• 12 total; used to grind food.• No primary molars.
DNA
Primary Dentition Labeling
• From the midline to the posterior the teeth are:
– Central Incisor– Lateral Incisor– Cuspid– Bicuspid (premolar 1)– Biscuspid (premolar 2)
Primary Dentition Labeling
• Looking at the child, starting at the top right working clockwise, the teeth are labeled A - T.
Secondary Dentition Labeling
• From the midline to the posterior the teeth are:– Central Incisor– Lateral Incisor– Cuspid– Bicuspid (premolar 1)– Bicuspid (premolar 2)– Molar (6 year old)– Molar (12 year old)– Molar (wisdom tooth)
Secondary Dentition Labeling
• Looking at the adult, starting at the top right and working clockwise, the teeth are labeled # 1-32.
Secondary Dentition
1. 3rd Molar (wisdom tooth)2. 2nd Molar (12-yr molar)3. 1st Molar (6-yr molar)4. 2nd Bicuspid 5. 1st Bicuspid 6. Cuspid (canine/eye tooth)7. Lateral incisor8. Central incisor9. Central incisor10. Lateral incisor11. Cuspid (canine/eye tooth)12. 1st Bicuspid 13. 2nd Bicuspid 14. 1st Molar (6-yr molar)15. 2nd Molar (12-yr molar)16. 3rd Molar (wisdom tooth)17. 3rd Molar (wisdom tooth)18. 2nd Molar (12-yr molar)19. 1st Molar (6-yr molar)20. 2nd Bicuspid 21. 1st Bicuspid22. Cuspid (canine/eye tooth)23. Lateral incisor24. Central incisor25. Central incisor26. Lateral incisor27. Cuspid (canine/eye tooth)28. 1st Bicuspid 29. 2nd Bicuspid 30. 1st Molar (6-yr molar)31. 2nd Molar (12-yr molar)32. 3rd Molar (wisdom tooth)
Source: American Dental Association "Current Dental Terminology Third Edition (CDT-3)" (c) 1999.
Primary Eruption Guidelines
Secondary Eruption Guidelines
Mixed Dentition - Skulls
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
2 year old
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
5 year old
X-rays of Mixed Dentition
Newborn Boy6 month old Girl
1 year old Girl9 month old Girl
2 year old Girl3 year old Girl
4 year old Boy 5 year old Boy
6 year old Boy 7 year old Boy
9 year old Boy 10 year old Boy
Postmortem Examination
• FOR IDENTIFICATION– If the body can be viewed at a funeral, the
forensic dentist examines in the mouth.• Rigor mortis must be broken.
– Myotomy (cutting of facial muscles)
– Jaws are removed if the body is not fit for viewing.
• 30% H2O2 for 24 hours to remove any remaining soft tissue.
Postmortem Examination• State presence or absence of each tooth
– If missing, socket or healed?• (Socket implies tooth was recently lost).
– If present, erupted or unerupted? • Filled? What materials?
– Gum disease? General anatomy?
• X-rays to compare to antemortem records.
Antemortem Examination
• Found at dental offices, military, prisons & hospitals.
• Need preliminary identification to search for antemortem records.
– Driver’s license, photo ID, etc…
Website for practice!
• www.forensicdentistryonline.org
• http://www.forensicdentistryonline.org/Fire_Folder/case1.htm
Mass Disasters• Team 1
– removal of jaws/teeth from the scene.
• Team 2 – postmortem exams at the morgue.– Shift <3 hours, max every other day.
• Team 3 – Antemortem exams & record collection.
• Team 4– Data posting into exams; both post & antemortem.
• Chief Forensic Dentist– Makes the actual identification.
Profiling
• Using the characteristics of the teeth to reduce the population from which one searches for the unidentified decedent.
Profiling 1
• Dental erosion on the inside (tongue side) of the teeth.
• Caused by excessive vomiting:– Bulimia– Alcoholism– Gastric problems
Profiling 2
• Severe staining – Top & bottom teeth
• Caused by antibiotic tetracycline.– Taken while teeth
were developing.
Profiling 3
• Abnormal tooth wear from pipe smoking.
Profiling 4
• Occupational Hazard…..?
– Electrician– Uses teeth to strip
plastic coating from wires.
Profiling 5
• Country of residence
– Performed in Russia.– Evidence of dentistry in
the former Soviet Union.
Profiling 6
• Personal Habits– Smoker– Poor personal oral
hygiene habits.
Bitemark Analysis
• Used to identify victims & assailants.
• Most common in cases of rape, murder, child abuse, & spousal abuse.– Attacker – bites on hands, shoulders– Victim – bites on breasts & buttocks.
• More useful on dead victims because of the lack of inflammatory response.
Bitemark Patterns
• Two (2) horseshoe patterns• Shape depends upon surface bitten,
biting force, & victim resistance.– Muscle = distinct pattern– Fat = less distinct pattern– Defensive bite = less distinct, more
bruising, tearing.– Offensive bite = distinct bite
Bitemark Severity & Significance Scale
• 1) Very mild bruising, no individual tooth marks present
• Diffuse arches visible; may be caused by something other than teeth
• Low forensic significance
Bitemark Severity & Significance Scale
• 2) Obvious bruising with individual, discrete areas associated with teeth.
• Skin remains intact.
• Moderate forensic significance
Bitemark Severity & Significance Scale
• 3. Very obvious bruising with small lacerations.
• Likely to be assessed as definite bitemark.
• High forensic significance
Bitemark Severity & Significance Scale
• 4) Numerous areas of laceration, with some bruising, some areas of the wound may be incised.
• Unlikely to be confused with any other injury mechanism.
• High forensic significance.
Bitemark Severity & Significance Scale
• 5) Partial avulsion of tissue, some lacerations present indicating teeth as the probable cause of the injury.
• Moderate forensic significance.
Bitemark Severity & Significance Scale
• 6) Complete avulsion of tissue, possibly some scalloping of the injury margins suggested that teeth may have been responsible for the injury.
• May not be an obvious bite injury.
• Low forensic significance
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