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 Application of dental science to the law deriving from any evidence that pertains to the teeth.

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Presentation on theme: " Application of dental science to the law deriving from any evidence that pertains to the teeth."— Presentation transcript:


2  Application of dental science to the law deriving from any evidence that pertains to the teeth

3  Practicing dentists › Specialized training to understand how to apply forensic science to dentistry  Most are members of a professional organization  DDS degree

4  Every human body ages in similar manner › Teeth follow semi-standardized pattern  Each human has an individual set of teeth  Teeth are made of enamel › Can withstand trauma - decomposition

5  Teeth are source of DNA › Dental pulp or crushed tooth can provide nuclear or mitochondrial DNA that can identify a person

6  Hardest part of body attached to jaw  Helps to digest food (chew)  Made up of a crown with enamel surrounding a pulp

7  Thin outer covering of the tooth  Hardest tissue in the human body  Covers the crown of the tooth  Reason why teeth can withstand high temperatures such as fire

8  Approximately 32 teeth in adult mouth  4 types: › Molars › Premolars (bicuspid) › Canine › Incisors  Teeth differ in size, shape, and root type



11  Primary teeth sprout from milk buds and are temporary  Fall out to make room for permanent teeth  Deciduous teeth = 20

12  Permanent adult teeth come in when primary teeth fall out  They are permanent because they establish roots inside the gums  Third molar come in around the mid teenage years

13 Dental Crown Dental Fillings

14  Size of tooth  Shape of tooth  Shape of root  Placement of tooth  Quantity of teeth  Combination of dental work done: › Crowns, extractions, bridge, fillings, root canals

15 Dental ExtractionDental Bridge

16  The Universal System › Teeth are given a specific number  Primary teeth are given specific capital letter › Any dental work done on surface is noted › Sheets kept on dental file forever - when person is missing, files are transferred to missing person office


18  Postmortem description is generated › X-Rays  Positive identification is compared to ante-mortem data  Negative identification – biological profile generated

19  Same process as individual identification  Organization is CRUCIAL  Family asked to identify the body, and narrow down the pool of victims


21  Mouth of a smoker  Mouth of a Meth user

22  There are cases where the victim no longer had teeth and wore dentures.  Records are also kept for dentures so this dental appliance is a very good source.

23  Earliest known ID from teeth was in 1775 by Paul Revere › Made a silver bridge for a man who died in the Revolutionary War › Body was in a mass grave and identified by his silver dental work

24  4 events in which an odontologist would be called: › Individual identification › Mass disaster identification › Bite mark analysis › Dental malpractice


26  Identifying factors: › Cavaties › Tooth pattern › General dental health neglect

27  Odontologists compare antemortem (before death) records with postmortem (after death) findings to determine if there is a positive match


29  Definition – impressions from teeth found on skin or items left at a scene › Outline teeth placement

30  Bite Marks Bite Marks

31  Impressions left on food, skin or other items left at a scene › Must be a porous surface that absorbs the impact enough to make impression  Impressions vary › Depends on pressure › More pressure = more defined mark


33  Saliva or blood can be left behind that can be tested for DNA  Dental records including X-Rays can also provide useful information


35  Photographed with a scale › Bite marks on skin taken over repeated intervals  Casts of impressions made  Impression traced onto transparency  Casts of suspects teeth taken  Comparison between suspect cast and bite marks

36  Type of bite mark (human or animal)  Characteristics of the teeth › Position, evidence of dental work, and wear patterns  Color of area to estimate how long ago the bite occurred (old or recent)  Swab for body fluids for DNA tests

37  Bite marks are found on both victims and suspects  Types of cases bite marks are most prevalent: › Sexual assaults › Battered or abused children

38  Females › Breasts and legs › Due to sexual assault  Males › Arms and shoulders › Due to fights

39  Other factors that can affect the way a bite mark looks: › The movement of the biters jaw and tongue when he or she bites › The location of the bite › Whether or not the biting victim was moving when he or she was bit › Number of teeth contacting skin

40  Over time, teeth may change › Lost teeth › Caps › Bridges › Also due to health, activity and dental treatment

41  Bite marks change their shape and size depending upon the amount of time that has elapsed and the nature of the material bearing the impression  Skin is elastic and distortable › Should photograph bite mark over time

42 Lindy and Michael Chamberlain were enjoying a family vacation camping near the famous Australian landmark of Ayer’s Rock On the night of August 17, 1980, Lindy cried out from the tend that a dingo (a wild Australian dog) had taken her baby Azaria from her bed

43 The disappearance was investigated and Lindy convicted of the murder of Azaria, whose body was never found. There were many doubts about the evidence that those representing the Chamberlains pursued through many years of trial and retrial, and finally a high-level judicial inquiry

44 Part of the evidence at the trial was forensic odontology. Damage to various items of the child’s bedding was examined, and the odontologist concluded that the marks were made by scissors and could not have been made by the teeth of a dog

45 However, the judicial inquiry heard that the action of canine incisors could well have caused the damage and confident assertions of the odontologist at trial was not dependable The bite mark evidence was declared unreliable and the conviction overturned

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