Identification of Burnt Victims Through Their Teeth

Today, let's learn how forensic scientists identify burnt victims through teeth identification :)

This is in regard to Question 1.

" QUESTION 1

We have all heard of how Forensic Dentistry has helped in the identification of burnt victims and also victims with bite marks. Explain more about these and describe how is Forensic Dentistry could be useful in the identification of murder victims?"

In the middle of one peaceful night when everyone in your neighborhood was sound asleep, one of the terraced houses a few streets away was caught on fire. When the fire engines arrived half an hour later, the fire turned uncontrollable and started to spread to the next few houses. The enraged fire continued to burn down the whole stretch of houses before the fire fighters managed to extinguish it two hours later. The next morning, the news reported several unidentified badly burnt casualties. You are the well-known forensic dentist in town. How do you help the victims’ families to retrieve the deceased’s bodies?     

It is often impossible to identify badly burnt victims by visual recognition of facial features. Moreover, identification by fingerprints may not be possible due to the degree of destruction of the bodies. Identification of individual victims by dental means is one of the most reliable methods particularly after a mass disaster. The mouth of every individual is unique due to the transformations brought about by age, pathological conditions, developmental disturbances of teeth, or dental treatment. Additionally, do you know that the teeth also survive most post-mortem episodes that damage or disrupt most body tissues? Now, let’s look at various forensic dental modalities of human identification after mass disaster.

Comparative Dental Identification

The foremost investigation is the comparative examination. With post-mortem dental findings at hand and the availability of ante-mortem dental records such as written notes, study casts and radiographs, comparison can be done to confirm identity.

The quality of ante-mortem dental records is categorized as follows:

―     Grade 0: No information

―     Grade 1: Information without written records

―     Grade 2: Written records only

―     Grade 3: Record combined with unsystematic radiograph

―     Grade 4: Record combined with bitewings

―     Grade 5: Record combined with full mouth survey or an orthopanthomograph

How do you go on producing post-mortem records? It is done based on careful charting and written description of dental structures and radiographs of the deceased. The following post-mortem details should be included:

·         Site of accident: car, boat, home, flight, vacation cabin, etc.

·         Severity of injury:

―     Grade 0: No injury

―     Grade 1: Injury to anterior teeth (in one or both jaws)

―     Grade 2: Injury to anterior and posterior teeth unilaterally (in one or both jaws)

―     Grade 3: Injury to anterior and posterior teeth bilaterally (in one or both jaws)

―     Grade 4: Fragment of both jaws including teeth and or roots.

―     Grade 5: No dental remains.

·         Dental registration:

―    Intact/sound, filled (restorative material specified), surfaces, root filling and missing teeth

―    Prosthesis: fixed (crowns and bridges) and removable prosthesis

―   Developmental disorders: impactions hypo and hyperdontia, ectopic, transposition or retained teeth

―    Malocclusions: mesial molar occlusion, frontal open and deep bite > 5mm, cross bite scissors bite, midline displacement, crowding and spacing.

― Evidence of pathological changes: jaw fractures, tumours, major infections (sinusitis, osteomyelitis)

After a systematic comparison of ante-mortem and post-mortem records of each tooth and adjoining structures such as bony prominences and congenital defects followed by dental restorations, similarities and discrepancies are documented. Individuals with several and complex restorations are usually easier to identify compared to those with few or no restorative treatment. Below are examples of post-mortem and ante-mortem dental radiographs: 

Post-mortem (a) and ante-mortem (b) dental radiographs with many restorations (dense radio opacity) (Picture adapted from: http://www.ajol.info/index.php/aipm/article/viewFile/71826/60782)

When reporting dental identification, the American Board of Forensic Odontologists recommended four conclusions:

• Positive identification: ante-mortem and post-mortem records match in details with no unexplainable discrepancies.
• Possible identification: ante-mortem and post-mortem data have consistent features but due to poor quality, identity cannot be positively established.
• Insufficient Evidence: available information is insufficient to form basis for a conclusion. 
• Exclusion: ante-mortem and post-mortem data are clearly inconsistent.

Post-mortem Dental Profiling

What do you do when the deceased has no previous ante-mortem records and no clues to positive identity exist? Under this circumstance, you have to limit the probable population to which a deceased belongs to and determine the characteristics of the individual by post-mortem dental profiling. Post-mortem dental profile narrows the search of the ante-mortem evidences and gives information on age, ancestral background, sex, and socioeconomic status of deceased.

You can establish the age of child victim by analysing their tooth development and then comparing with development chart. Whereas in older individual, periodontal disease development, excessive wears, numerous restorations, extractions, bone pathology and complex restorative work may be present. In cases of damaged dentition, restorative materials such as resin can be examined and analysed with Scanning Electron Microscope / Energy Dispersive X-ray Spectroscopy (SEM/EDXS). Since the inorganic composition of resin is hardly modified, each spectrum can be paired to a specific brand name. This gives information about the time frame that the product was in market hence suggesting the chronology of the remains.

The deceased’s skull shape and form can provide information about ancestry and sex. The three major race groups – caucasoid, mongoloid and negroid – exhibit distinctive skull appearance and tooth features such as cusp of Carrabelle, shovel shaped incisors and multi cusped premolars. The relationship between skull appearance and sex will be discussed later. Besides skull, sex of the deceased can also be determined by the presence or absence of y-chromatin through microscopic examination of teeth.

Post-mortem dental profile can give clues to socio-economic status such as occupation, dietary habits, and habitual behaviours, dental or systemic diseases. For instance, presence of erosion may indicate alcohol or substance abuse, or eating disorder while stains may suggest smoking, tetracycline use or betel nut chewing. Cigarette holders, hairpins, or previous orthodontic treatment can result in unusual dentition wear. An individual’s socioeconomic status or country of residence may be reflected by the quality, quantity, presence or absence of dental treatment.

References:

http://www.ugr.es/~dpto_legaltoxicops/medicinalegal/investigacion/publicaciones/dental%20methods%20IJLM.pdf

http://www.ajol.info/index.php/aipm/article/viewFile/71826/60782

Real cases : Dental methods of identification to human burn victims 

HEADLINE: Identification of 28 Burnt Victims Following a 1996 Bus Accident in Spain

A car collided head-on with a bus at 10pm on 28 February 1996 on a major highway in Southern Spain. Few seconds after the collision, the bus caught fire and 28 out of 57 passengers lost their lives! Complete postmortem examinations of 28 victims have to be performed by a multidisciplinary identification commission (ID-Commission). It will be consisted of ten police officers, two forensic odontologists and pathologist, two odontologists, one forensic pathologist and an assistant radiologist. 28 bodies (13 females and 15 males) were examined for identification. Mean age of victims was 22 years (age range 5-48 years) and 17 victims were under 20 years of age. Standard postmortem forensic procedures, including general external examination of each victim, routine photographs, general radiographs, DNA analysis have to be performed. More importantly, postmortem dental examination and dental comparison process have to be carried out too.

**Do you wonder what are the procedure involved in this victims identifications??! Let’s find out together!! ^^

First, you have to carry out the postmortem dental examination process one by one~~

Postmortem dental examination procedure:

This procedure is needed to be carried out by two odontologists per case (1 forensic & 1 general dentist)

Your hard work has to include oral macrophotography, postmortem pink Interpol DVI form completion and radiography. A detailed postmortem registration of the teeth has to be performed in each case using categories:

• Intact/sound, filled( restoration material, surfaces, root fillings)
• Missing teeth (extraction, postmortem loss) and fixed (crowns and bridges) or removable prosthetics.
• Disturbances in tooth eruption (ectopic, transposed, retained, impacted teeth)
• Various types of malocclusion (deep bite, crossbite, crowding and spacing)
• Fractures of teeth and jawbones and any pathological changes in soft tissues or jawbones (Infections, torus palatinae) 

Dental Radiography

Taken from howardfamilydental.blogspot.com

postmortem pink Interpol DVI

taken from dvi-training.info

Torus Palatinae

Taken from nycdentist.com

Dental Radiography

Taken from howardfamilydental.blogspot.com

Then, you have to carry out radiography session!! Here we go!!

Take Postmortem dental radiographs in most cases, periapical and extraoral (lateral and posteroanterior) skull radiographs. Extraoral radiographs were meant for determination of age by dental eruption and mineralization of permanent and deciduous teeth. After that, you are required to take Intra-oral radiograph (occlusal and periapical) to identify victims through the study of disturbances in tooth eruption, incomplete extraction of a molar or specific dental treatment.

Extra-oral Radiography

Taken from lar.carestreamdental.com

Intra-oral Radiography

Taken from ensodentistry.com

 

**Do you find these radiographs interesting??! These are the clues to solve the mysteries!!! Let’s collect more clues!! But!! How??

What about the information before death??

Collection of antemortem material and comparative identification

 After the accident, you have to compile a complete list of the passengers and collect most of the technical information from inquiries from other passenger and relatives. Antemortem photographs of victims can be supplied by relatives. Dentists and family doctors of the victims can provide dental and medical information. After these collections, the most important part is to transcribe the information onto the Interpol DVI forms (detailed antemortem and postmortem records) only by forensic pathologists and odontologists. General dental practitioners can help to interpret their own patients’ dental charts so that mistakes made in transcription of dental antemortem data into the Interpol DVI forms could be minimized.

Then, try your best to compare Interpol DVI forms and radiographs  by dividing you all into two separate teams, one for the group of male victims and the other for female victims. Results obtained were discussed between the two teams in order to make comparable conclusions. The table shown below can be an example for reference.

 

Category	Pathological findings	Age (years)	Sex	Specific Observations	Radiographs
1. Oral Pathology	Disturbances of tooth eruption	12	M	Ectopic upper lateral incisors	Occlusal
	Malocclusions	13	M	Expansion plaque	None
	Dental pathology	30	M	Deep Carious Lesions	Periapical
	Pathological changes in bones	11	M	Torus Palatinae	None
2. Dental Treatment	Fillings	20	F	Amalgams	Periapical
		17	M	Composites	Periapical
		19	M	Molar Sealants	None
	Root canal treatment	15	M	Root filling	Periapical
	Extracted teeth	46	F	Multiple extractions	None
3.Establishment of dental age	Dental eruption and mineralization	9	M		Lateral skull
		5	F		Lateral skull

 Table 1: Pathological findings and type of radiographs used for dental identification. (taken from A. Valenzuela et al.: Dental method for human identification)

Your results presented will demonstrate the success of the dental method alone for the identification of burn victims. You can conclude that the odontological and other complementary dental radiographic procedures may be powerful methods of identification when dealing with burn victims, especially when other types of evidence are not available.

 It is essential to emphasize the need for a standardized system of recording dental findings. A well trained team of experienced forensic odontologists should be prepared to operate when a mass disaster occurs.

References:

1.       A. Valenzuela et al.: Dental method for human identification http://www.ugr.es/~dpto_legaltoxicops/medicinalegal/investigacion/publicaciones/dental%20methods%20IJLM.pdf