Forensic odontology

Forensic Odontology

Presented by

Group 1

• Adeen

Farooq

• Beenish

Sarfraz

• Hina qaiser

• Medhat sabir

• Rabia aslam

Why Teeth

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

Teeth is made of enamel (hardest tissue of the body) so it can 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.

Forensic Dentistry or

Forensic Odontology

Definition:

Forensic – Forum means ‘Court of Law’

Odontology – Study of teeth

• Branch of forensic sciences which deals with

collecting, preserving, recording and

interpretation of dental evidence at the interest

of court of law to offer law enforcement.

• History of forensic dentistry dates back 4500 years

• One of the first dental identification was recorded in 2500 BC, when 2 molars linked together by gold wire were found by Junker in a tomb located at Giza

• 17th century : identification of bodies using dental details known to dentist

• German dictator ADOLF HITLER and Pakistani President General ZIA-UL-HAQ were identified on the basis of dental evidences

• 19th century: criminal convicted on dental evidence

• In 1897, first paper on forensic odontology published

• In 1906, first time in history bite marks accepted as an evidence, person was convicted for murder on this basis.

History of Forensic Dentistry

Father of Forensic Odontology Dr. OSCAR AMOEDA

Subject Division

Forensic odontology

Civil

1. mal practice2. Identification of bodies3. Natural disasters

Identification of a living person- loss of

memory.

Criminal

The identification of persons from their teeth - living/dead

person.

Bite marks - food stuff, on the assailant, on the

victim- self inflicted/inflicted by

another

Research

Academic training

Organizations of Forensic Odontology

Bureau of Legal Dentistry (BOLD)

American Board of Forensic Odontology (ABFO)

International Organization for Forensic Odonto-Stomatology (IOFOS)

Teeth Basics

• Approximately 32 teeth in adult mouth

• Four types of teeth:

• Molars

• Premolars

• Canine

• Incisors

• Teeth differ in:

• Size

• Shape

• Root typeTypes of teeth

Left to right: Incisor, Canine, Premolar, molar.

Individual Characteristics

Size of tooth

Shape of tooth

Shape of root

Placement of tooth

Quantity of teeth

Combinations of dental work done:

Crowns

Extractions

Bridge

Fillings

Root canals

Various d

ental w

ork

Childhood Adulthood

Teeth Through the Years

Primary teeth sprout from milk buds and are temporary. Once they fall out, permanent teeth as

seen on the other side appear.

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.

Dental Identification is Used Identify human remains that cannot be

identified using face recognition, fingerprints or other means

Identify bodies in mass fatalities, such as plane crashes and natural disasters

Determine the source of bite mark injuries, in cases of assault or suspected

abuse

Estimate the age of skeletal remains

Testify in cases of dental malpractice

1. Routine identification

unknown human remains in various stages of decomposition.

Analyze the dentition of the deceased. Record all the restorations, anomalies, missing teeth

Radiographic and photographic records of the dental arches.

2. Mass Disasters

Identification of people in mass disasters.

3. Bitemark evidence

Identification, examination & evaluation of bite marks – sexual assaults, child abuse, personal defense situations.

Role of Forensic Odontology

4. Civil Litigation

Examination of patients sustaining trauma due to accident, assault, negligence or malpractice – supported with radiographs, photographs etc.

5. Age Estimation

Estimation of both the living and the deceased.

6. Sex Determination

Determining the gender of unidentified individuals.

7. Other methods of Identification

Cheiloscopy (Study of lip prints)

Rugoscopy (Study of palatal rugae patterns)

Sialochemistry (Detection of Chemicals in Saliva)

Dental Identification Kit

PROTECTIVE CLOTHING DENTAL INSTRUMENTS

RECORDING THE DATAIMPRESSION MATERIALS

PHOTOGRAPHY

There are three main forms of dental identification

• Comparative Identification

• most frequently performed examination

• to establish the remains of a decedent and a person represented by ante mortem records are of the same individual.

• Reconstructive Identification - Dental profiling or Post-mortem Dental profile

• elicit race, gender, age & occupation of the dead individual

• undertaken when ante-mortem records are not available.

• Identification in mass disasters

• identification of victims in mass disasters

Forms of Dental Identification

I. Comparative Dental IdentificationConventional method of identification includes four stepsA) Oral Autopsy• dissection to expose the organs, to determine the cause of death• oral examination – essential partB) Obtaining Dental Records• Contains information of treatment & dental status during his/her life.• Obtained from treating dentist, specialist or hospital records – in the form

of dental charts, radiographs, casts & / or photographsC) Comparing post and ante-mortem dental records• Compared by written notes, Study casts, radiographs, Photographs etc.,D) Writing a report & drawing conclusions

Most Common Points for Comparison Include

1. The no. of teeth – Missing, impacted, supernumerary2. Restorations & Prosthesis – Tooth no., surfaces involved, dental materials used

- type of material, no. of replaced teeth.3. Dental Caries – Surface & configuration4. Malposition & Rotation5. Anomalous tooth formation – extra cusps, peg-shaped incisors, fused teeth6. Root canal therapy – Type of filling material used, imperfections of the canal

II. DENTAL PROFILING

[Reconstructive identification (or) post – mortem dental proile]

It includes the decedent’s

A. ETHNIC ORIGIN [Race determination]

B. GENDER [Sex determination]

C. AGE [Age estimation]

A. Race determination:

The quality and type of dental treatment may indicate an individual's country of residence: a) Dental

treatment of high quality, which is consistent with North American and European standards. b)

Unusual dental treatments involving the use of permanent acrylic and stainless steel crowns. This

treatment was performed in Russia

B. Sex Determination:Generally teeth are smaller in females Teeth – used for differentiating sex by measuring mesiodistal & buccolingual dimensions Canines – show max. sex differenceMand. Canines show greatest dimensional difference, being larger in males

SEX DETERMINATION BY DNA ANALYSIS a. From pulp tissue:- Y chromosome analysis from dental pulp of male can be done even after 1yr. of death b. From enamel protein [Amelogenin]:-

Amelogenin[AMEL] – Major matrix proteins secreted by the ameloblasts of the enamel

AMEL gene located on X & Y – chromosomes in humans c. From Buccal Mucosa:- Barr bodies & x-chromosomes of female detected from buccal mucosal epithelium.

C. Age Estimation:

Important Subspeciality of forensic sciences

Also has application in living individuals

Dental Age Estimation Methods

a. Morphologic / visual Examination

b. Radiographic Examination

c. Histological Examination and

d. Biochemical Examination

The determination of D- and L-aspartic acid (Asp) content from teeth has been applied in age estimation for forensic purposes over the past decades.

It was first introduced to assess age from tooth enamel and later from dentin.

III. Identification of mass disasterDisasters: refers to natural calamities such as earthquakes, floods

and tsunami and accidental or man-made events such as airplane crashes or terrorist attacks-that result in multiple human fatalities. Such incidents require identification of the post-mortem remains due to severe mutilation.

Identification from Dental DNA

Teeth - Excellent source of DNA

PCR (Polymerase chain reaction)– amplifies highly degraded DNA

compared with ante-mortem sample of the decedent (hair from a hair brush, epithelial cells from a tooth brush or a biopsy specimen)

Major Advantage:– DNA Pattern may be compared to a parent or a sibling, if ante-mortem sample

is unavailable.Types of DNA

1. Genomic or Nuclear DNA – Commonly used

2. Mitochondrial DNA (mt DNA) – substituted if nuclear DNA is unavailable

Genomic DNA

• Genomic DNA is found in the nucleus of each cell and represents the DNA source for most forensic applications, (there are no nuclei, and hence there is no DNA, in red blood cells.)

• When body tissues have decomposed, the structures of the enamel, dentine and pulp complex persist.

• It is necessary to extract the DNA from the calcified tissues. the cryogenic grinding method is best employed for DNA extraction.

Extraction of Dental DNA

CRYOGENIC GRINDING – Coding the whole tooth to extremely low temp., using liquid nitrogen & grinding it to fine powder.Major drawback is tooth needs to be completely crushed.Less destructive method is drilling the root canals & scraping the pulp area.

Cryogenic grinding is used to extract DNA from calcified tissues such as teeth. In a freezermill a ferromagnetic plunger is oscillated back-and-forth in alternating electric current. Liquid nitrogen is used to cool the sample, which results in making it extremely brittle and also protects DNA from heat degradation. The tooth is reduced to a powder to increase surface area and expose trapped cells to biochemical agents that release DNA into solution

Bite Marks

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

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Need for dental identification

• Decomposing remains

• Skeletonized remains

• Charred remains

• Doe Identification ; Intact remains without any putative victim

• Scientific verification of identity is anticipated

• Multiple bodies recovered from a common location

• Mass disaster

Analyzing bite marks

Bite marks are photographed with a scale

Bite marks on skin are taken over repeated intervals

Casts of impression are taken

Impression traced onto transparencies

Casts of suspects teeth are taken

Comparison between suspect cast and bite mark


Site of Bite Marks

• Females on breast, legs( inner part of thigh)-sexual assault

• Children genitals, oral & paraoral regions-child abuse

• Adult Males finger, arms and shoulders-fight

Various Bite Marks

Computer Odontology Automatic dental code matching

Bites are run through the computer to find a match

OdontoSearch

Compare a data base of missing peoples, felons, government workers

Automatic dental identification system

A few minutes will produce a list of people who have the same dental code number

3D Bite mark analysis

3D scans of dental casts are used to generate overlays using various pressure and deviation.

The overlays are compared with the photograph of the bite marks.

Classification of bite marks

1. Cameron and Sims Classification

based on the type of agent producing the bite mark and the material exhibiting it.

• Agents

• Human

• Animal

• Materials

• Skin, body tissue

• Foodstuff

• Other materials.

2. MacDonald's Classification.

suggested an etiologic classification.

• Tooth pressure marks: Marks produced on tissue as a result of "direct application of pressure by teeth". These are generally produced by the incisal or occlusal surfaces of teeth.

• Tongue pressure marks: When sufficient amount of tissue is taken into the mouth, the tongue presses it against rigid areas such as the lingual surfaces of teeth and palatal Rugae. The marks thus left on the skin are referred to as 'suckling,' since there is a combination of sucking and tongue thrusting involved.

• Tooth scrape marks: These are marks caused due to scraping of teeth across the bitten material. They are usually caused by anterior teeth, and present as scratches or superficial abrasions.

Tooth and tongue pressure marks

Bite marks on cheese

1. Odontometric triangle method

• In this objective method a triangle is made on the tracing of bite marks and teeth models by marking three points, two on the outer most convex point of canines and one in the centre of the upper central incisors.

• Three angles of the triangles are measured and compared.

• A clinico-anthropological study carried out by Manohar Singh et al by comparing bitemark width, bizygomatic and bigonial width concluded that from a given bitemark impression the facial dimensions of a person who is responsible for the mark can be determined

Methods of Analysis of Bite Marks

2. Rugoscopy - The palatal rugae in identification

Useful method in edentulous individuals

Rugae pattern – unique to an individual.

• The rugae pattern on the deceased's maxilla or maxillary denture may be compared to old dentures that may be recovered from the decedent's residence or plaster models that may be available with the treating dentist.

Rugae Pattern

3. Cheiloscopy - Examination of lip prints

• Cheiloscopy is a forensic investigation technique that deals with identification of humans based on lips traces.

• Lip prints have to be obtained within 24 hours of time of death to prevent erroneous data that would result from post mortem alterations of lip.

• Lip print pattern depends on whether mouth is opened or closed.

• In closed mouth position lip exhibits well defined grooves, where as in open position the groves are relatively ill defined and difficult to interpret

• Lip prints are usually left at crime scenes and can provide a direct link to the suspect.

• Traditionally, the use of lipsticks was essential to leave behind colored traces of lip prints.

• In recent years, however, lipsticks have been developed that do not leave any visible trace after contact with surfaces such as glass, clothing, cutlery or cigarette butts.

• Nevertheless, these lipstick marks are characterized by their permanence and produce 'persistent' lip prints that can be recovered days after being produced.

• Although invisible, Alvarez and associates have shown that these prints can be developed and visualized using agents such as aluminium powder and magnetic powder.

• It is also interesting to note that the use of lipsticks is not indispensable for leaving lip prints.


Positive bite-mark Possible bite-mark Definite bite-mark

•An 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.

•• criteria: general shape and size are present but distinctive features such as tooth marks are missing, incomplete or distorted or a few marks resembling tooth marks are present but the arch configuration is missing.

•The pattern strongly suggests or supports origin from teeth but could conceivably be caused by something else.

•• criteria: pattern shows (some) (basic) (general) characteristics of teeth arranged around arches.

•There is no reasonable doubt that teeth created the pattern; other possibilities were considered and excluded.

•• criteria: pattern conclusively illustrates (classic features) (all the characteristics) (typical class characteristics) of dental arches and human teeth in proper arrangement so that it is recognizable as an impression of the human dentition.

Inference


Oral findings of child abuse/maltreatment

Findings Cause

Multiple broken, discolored, missing or avulsed teeth

Repeated episodes of mouth trauma

Peculiar malocclusions & non occluding jaw segments

Healed jaw fractures which were displaced

Laceration of labial or lingual frena Forceful lip pulling or slapping

Isolated laceration of soft palate Insertion of utensils during forced feeding

Horizontal abrasions or contusions extending from lip commissures

Application of gag

Bite marks on skin Child bite (unsupervised children), adult bite (anger biting)

Rampant caries/Nursing Bottle Syndrome Possible child neglect

Venereal disease Gonococcal stomatitis, syphlitic lesions indicates sexual abuse

• In one study,the lips were the most common site for inflicted oral injuries (54%), followed by the oral mucosa, teeth, gingivae, and tongue.

• Discolored teeth, indicating pulpal necrosis, may result from previous trauma.

• Gags applied to the mouth may result in bruises, lichenification, or scarring at the corners of the mouth.

Tear of labial frenum Trauma to lip Fracture of tooth

• The roles of any forensic scientist are to collect, preserve and interpret trace evidence, then to relay the results to the judicial authority in a form of a report.

• Forensic Odontology is the forensic science that is concerned with dental evidence.

• Dental practitioners should be aware of the forensic application of dentistry.

• Dental records that are used to provide patients with optimal dental service could also be very beneficial to legal authorities during an identification process.

• Therefore, all forms of dental treatments should be recorded and kept properly.

Conclusion

• "Forensic Odontology." Monkeyshines on Health and Science 2003: 14.

• Graves, Chris. Sorting out a mouthful of clues. Minneapolis: Star Tribune, 2000.

• Lotter, Karen. Taking a look at Human Bite Marks. 2008. 27 November 2010 <www.asfo.org/news>.

• McRoberts, Flynn and Steve Mills. Testimony on Bite Marks Prone to Error. Chicago: Chicago Tribune, 2004.

• Weigler, S. "Bite Mark Evidence: Forensic Odontology and the Law." Journal of Law Medicine (1992): 303.

• Bowers CM. Forensic Dental Evidence: An Investigator's Handbook. San Diego, Calif: Academic Press; 2004.

• Dorion RBJ, ed. Bitemark Evidence. New York, NY: Marcel Dekker; 2005.

• Fixott RH, ed. The Dental Clinics of North America (Forensic Odontology).Philadelphia, Pa: WB Saunders Company; 2001:45(2).

References

Thank you….