Question 5 (Part 1): The Evidence Presented

Question 5:

List the evidences that have been presented to both the doctors.

Picture 1: Adult's skull & jaw

Let’s look at the mandible. It bears five teeth, including three molars on the right and two molars (second and third molars) on the left. Eleven tooth sockets with missing teeth can also be clearly seen. We can thus deduce that this mandible belongs to an adult above the age of 17 due to the presence of third molars. However, we cannot predict the gender of the victim by looking at the mandible alone.

The skull here portrays rounded supraorbital ridge. It could belong to a male. Fragment of bone consisting tooth sockets is present. Further investigations need to be performed to gather more information before we jump into conclusion.

Picture 2: Pieces of a jaw

This piece of evidence shows the anterior view of a mandible bearing three molars on the right side. The other feature which we can appreciate is the angle of mandible is more acute. Besides, it displays a prominent gonial eversion of mandible. We may presume that the victim is probably a male adult.

Picture here shows the posterior view of the same piece of mandible. 

Closer look at the lower right molars! Note the presence of caries on the lower first permanent molar, as well as fissure sealant on the third molar. These bits and pieces of information are useful enough for us to look up the dental records of missing persons and see if we are lucky enough to get a match! 

Picture 3: Child's jaw

How can we tell that this mandible belongs to a child? As you can see, the mandible is smaller than that of adult. The child dentitions are incomplete because not all the teeth had fully erupted. The remarkable anterior tooth shown here could be a canine. As lower deciduous canine erupts between 17-23 months, the child should be approximately 2 years old.

The Dental Tooth Fairies

With the exponential rise of crime and disasters around the world in the era of 2013, panic and anxiety starts to hit the population of community in IMU as the amount of weird unsolved cases starts to pile up. Henceforth, the IMU committees had come up with an idea to put together a team of dental forensics who specialise in particular skills, whom will get the job done. People whom aren’t afraid to get their hands dirty and inflict fear upon crime offenders. The silent protectors, the watchful guardians of the IMU community, the Dental Tooth Fairies! So, sit back, relax and enjoy the progress of the Dental Tooth Fairies for these upcoming few weeks.

Introduction to Forensic Dentistry

Before my team and I can actually start bringing you guys to embark on this adventurous journey on how we tackle cases, first of all, we have to explain briefly the roles of a forensic dentist.

In this 21st century era, with crime rates increasing together with the advancement in science and technology, a new eye-opening world of forensic science is introduced to help solve cases which puzzle even the wisest of man. No matter how careful, smart or even experienced a criminal is, clues such fingerprints, footprints, body fluids, bones, teeth and even bite marks are always left behind. Maybe this is one way God made man to be imperfect to a certain extent that criminals will always be put behind bars.

If you choose to walk down the part of forensic dentistry with us in the future, you shall be known as a “FORENSIC ODONTOLOGIST”. Before that, we will like you to discover the important roles that you play in a forensic team as crime solving is definitely not a one man's job, and even the great Sherlock Holmes had a dear friend to help him through thick and thin.




The word 'Forensic' comes from a latin word 'Forensis' meaning with regards to having a discussion or debate. Basically, you will work as a regular dentist, but trained with high level of experience to help in identifying unknown remains and bite marks on a specific individuals. You will be called to perform forensic examinations as requested by local law enforcement or your medical colleagues of forensic pathologist, expect to be called in by police officers, medical examiner or even coroner (an officer who holds inquests in regard to violent, sudden, or unexplained deaths). Forensic odontology requires attention to collect details and the ability to work patiently so as to complete a lengthy step-by-step process without rushing.

Below are examples of cases a Forensic Odontologist will be called in:

• Identify human remains that can no longer be identified.
• Determine the source of bite mark injuries, in cases of suspected abuse, murder, rape and etc.
• Identify bodies in mass fatalities such as accidents (aeroplane crash) and natural disasters.
• Estimate the age of skeletal remains.
• Ethnicity of the victim is unknown.
• Sex identification.
• Testify in cases of dental malpractice.

Henceforth, you will be dealing with most of the cases that are related to oral cavity. Since crimes and disasters can happen at any time, you will receive “on-call” regardless of where you are and what you are doing, and you will be required to enter the area of crime scene. These investigation of crimes and mass disasters can be sometimes be emotionally disturbing, and drain even the most trained professional mentally and physically.

Otherwise, you'll have to attend the autopsy session and take photographs, measuring the skull, take dental impressions and x-rays from the remains. Besides that, you will have to compare the exemplars to those already known missing individuals and if a match is made, you are able to identify the remains. Forensic Dentistry demands for extremely fine motor skills and requires extraordinary precision as well as accuracy. Imagine a person with the mind of Sherlock Holmes, but with the hands of Michelangelo.

Apart from that, you have to write an accurate and complete detailed report to explain the procedures done and what conclusions can be made based solely on the physical evidence available. The report done will be used in court and you will be asked to explain and testify your conclusions.

Below is a video by Doctor Larry Klein regarding the job description of a Forensic Odontologist.

Question 1 (Part 1): Identification of Victims with Bite Marks

Picture adapted from www.uthealthleader.org

Forensic odontologists play a vital role in identification of victims with bite marks. As we all know, tooth is the hardest structure found in human beings. During violent assaults such as sexual assault, rape, physical abuse, and murder, teeth can be used as an effective weapon. Victims often use their teeth as a self-defensive weapon to inflict injury on assailants. On the other hand, assailants are commonly known to attack the victims by biting them intentionally due to their enraged manner, especially in the case of child abuse. Distinct bite marks has the potential to link the assailant and the victim.  

Analysis, Comparison & Identification

Picture adapted from www.nlm.nih.gov

In bite mark analysis, bite marks with unique traits are used to compare with the suspect’s teeth imprint pattern tracings. Note that the bite marks must first be established as a human bite mark by identifying specific types of teeth via their class characteristics. 

Presence of some characteristics in the injury such as rotations, malocclusions, fractures, restorations, congenital malformations and etc could facilitate the forensic dentist to analyse the bite marks. However, the overall significance of bite marks can be decreased when these features are absent in the injury. 

Forensic dentist must understand tooth morphology, dental arch characteristics, occlusions and etc thoroughly in order to carry out bite mark analysis accurately.

How are evidences collected from bite victim?

Picture adapted from www.utforensic.org

Dental forensic examiner, despite recording the documentation of physical appearance, size, orientation and location of bite marks, must take close-up photographs using intra-oral camera with a reference scale to allow following measurements. Albeit both colour and black-and-white film photography remain as the standard, digital photography are well-accepted. Subcutaneous evidence of bite mark damage can be identified by using infrared photography.

Saliva swabs (if applicable) should be collected from the bitten surface on the victim along with a DNA sample. These will later be analysed and amplified (eg: Polymerase Chain Reaction (PCR) analysis) to make comparison between the samples and bite marks, resulting in identifying association between the biter and the injury.

A precise impression of the bitten surface should be taken in order to inspect the presence of any irregularities caused by the teeth.

How are evidences collected from bite suspect?

It is necessary to perform a clinical examination on the suspect, including extra-oral and intra-oral examinations. Extensive photographs, impressions as well as bite sample should be collected for subsequent analysis. These procedures could only be done after obtaining a court-ordered search warrant.

Summary

Forensic dentistry field is still working until today to increase the scientific validity for human bite marks to provide adequate evidence for jurisprudence purpose.

Reference: http://www.forensic-dentistry.info/wp/?page_id=9

Question 1 (Part 2): Forensic Dentistry in Identification of Burnt Victims

A body that has been only partially burned can be identified through DNA fingerprinting.

But what if the body has been severely burned?

Fingerprints are not a viable option for identification anymore as the skin has burned!

This is when dental means play a key role in identification of the body.

Among human remains, teeth last longer than any body part, including bone. Even in the most severe burning, it is rare that "some fragments of dental evidence" wouldn't exist.

Comparative Dental Identification
The postmortem (after-death) dental remains can be compared with antemortem (before-death) dental records, including written notes, study casts, radiographs etc. to confirm identity. A presumptive identification usually can be made by using data from the missing persons’ database. Respective antemortem (AM) records are then obtained from the dentists of records.

The forensic dentist produces the postmortem (PM) record by careful charting, written descriptions of the dental structures and radiographs. Then, a methodical, systematic comparison can be done between the PM and AM records. Each tooth and surrounding structures are examined.


       Figure 1: Sample of Postmortem (PM) Odontogram

The following features may give some clues for the identification:
1. filled teeth with restorative material specified
2. missing teeth
3. fixed (crowns and bridges) and removable prosthesis
4. hypodontia, hyperdontia, transposition or retained teeth
5. malocclusions: mesial molar occlusion, frontal open and deep bite > 5mm, cross bite scissors bite, midline displacement, crowding and spacing
6. palatal rugae (able to sustain burns to some extent)

Similarities and discrepancies should be noted during the comparison process. There are two types of discrepancy, those that can be explained and those that cannot. Explainable discrepancies normally relate to the time elapsed between the AM and PM records. If a discrepancy is unexplainable, for example a tooth is not present on the AM record but is present on the PM record then an exclusion must be made.


Figure 2: Explainable discrepancies of AM PM comparison

When reporting dental identification, The American Board of Forensic Odontology recommends that the conclusions should be limited to the following four:
1. Positive identification: The AM and PM data match in sufficient detail, with no unexplainable discrepancies, to establish that they are from the same individual.
2. Possible identification: the AM and PM data have consistent features but, because of the quality of either the PM remains or the AM evidence, it is not possible to establish identity positively.
3. Insufficient evidence: The available information is insufficient to form the basis for a conclusion.
4. Exclusion: the AM and PM data are clearly inconsistent.

Postmortem (PM) dental profiling
In those cases where AM records are not available, and no clues to the possible identity exist, the forensic dentist provides a PM dental profile which suggests characteristics of the individual that helps to narrow the search for the AM materials. A postmortem dental profile will typically provide information on the deceased’s age, ancestry background, sex and socio-economic status. In some instances it is possible to provide additional information regarding occupation, dietary habits, habitual behaviours and occasionally on dental or systemic diseases.

If the PM profile does not elicit the tentative identity of the deceased it may be necessary to reconstruct the individual’s appearance during life. This is the responsibility of forensic artists who use the dental profile to help with the facial reproduction.

☂     References    ☂
1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3470417/
2. http://edition.cnn.com/2013/02/13/health/burned-body-id/index.html
3. http://voices.yahoo.com/forensic-science-applied-burned-victims-136748.html
4. http://www.forensic-dentistry.info/wp/?page_id=4

Question 1 (Part 3): Identification of Murder Victims

Describe how is Forensic Dentistry could be useful in the identification of murder victims?

The theory underlying forensic odontology is that no two mouths are alike; an individual’s dentition is believed to be unique.

Death Body Identification Techniques:

Comparison of antemortem and postmortem records,
Antemortem (before death – depends on known characteristics of a missing individual) 
Postmortem (after death – depends on recovered characteristics from an unknown body)

        at the points of comparison (specific features),

(a) the number, class, and type of teeth;

(b) tooth rotation, spacing, and malposition;

(c) anomalies and general morphology;

(d) restorations and prostheses or appliance);

            (e) caries and other pathology;

            (f) endodontic treatment;

            (g) implants and surgical repairs;

            (h) bony trabecular patterns

            (i)occlusion, erosion, and attrition.

through the dental radiographs, photographs, impressions and casts.

1.Dental radiographs – accurate dental identification requires point-by-point comparison of set of intraoral radiographs, which can be made as many as 18 to 21 images, in which all points of comparison must match exactly or in which differences must be explained.

Comparison of antemortem and postmortem radiographs looking for similarities of restorations and general morphology.

A. Antemortem radiographs of the same victim demonstrate multiple dental restorations, unique root and sinus morphology, pulp chamber shape, interdental bone height, and trabecular patterns.

B. Postmortem radiographs show consistency in some restorations when compared to the antemortem radiographs, but note that several teeth have had restorations placed after the antemortem radiographs were obtained.

2.Photographs

                

                Comparison of antemortem and postmortem photographs looking for similarities in general morphology.

A. Antemortem dental photograph showing gingival clefting.

B. Postmortem photograph showing similar clefting found in the victim at autopsy. Similar dental arch form is observed as is the overall morphology of the dental coronal structure.

                3.Radiographs and Photographs

Comparison of antemortem radiographs with postmortem findings (photographs).

A. These radiographs show antemortem (top) and postmortem (bottom) radiographs of a homicide victim with orthodontic appliances in place, which are identical to actual postmortem findings (seen in B and C) and served to confirm the identity. Note also the restoration of tooth No. 10, a peg lateral that matches as well.

B. This postmortem photograph shows the orthodontic retainer in the mandibular arch as evident in the antemortem radiographs.

C. This postmortem photograph shows the orthodontic retainer in the maxillary arch as evident in the antemortem radiographs.





reference:Scheid, R.C, Weiss Gabriela. Woelfel’s Dental Anatomy: It’s Relevance to Dentistry. 8th ed. Lippincott Williams & Wilkins

Question 2: Male or Female?

Question 2 - Is a male human skull different from that of a female? If yes, how?

So now we shall proceed with question 2 of part 1 ! Gender is an important aspect in forensic dentistry and is one of the key features to be identified.

Okay, okay. We already know that men are from Mars and women are from Venus. Of course, there are lots of differences between us that will reiterate that statement, but, from a dental standpoint, are our teeth so different from one another that they too are from an alien planet?

But before we begin brainstorming on this interesting aspect, we should first understand the anatomy of the skull! And here (below) is a very simple and easy to understand video on the anatomy of the skull!

Anatomy of Skull

Now that we obtained a clear understanding of the anatomy of the skull, we can attempt in figuring the gender of the child! BUT hold on right there!

A very important note to be clear is that it is generally not possible to give a gender to the skull, as it has not passed puberty and is starting to show some of the characteristics appropriate to its sex. Since the hormones are yet to wake up and carry out their amazing jobs, the sex of the child is nowhere near to be identified.

HOWEVER, there are a few features whereby (forensic dentists) can look out for and keep an extra eye for these few features, all listed below!

  

Skull (Cranium and Mandible)

Male Skulls:

• Generally larger than female.
• Larger projections behind the ears.
• Larger brow ridges, with sloping, less rounded (mastoid processes) forehead.
• Square chin with a more vertical greater definition of muscle attachment areas (acute) angle of the jaw on the back of the head. 

 

Female Skulls:

• Smoother bone surfaces where muscles attach (mastoid processes).
• Smaller projections behind the ears.
• Less pronounced brow ridges, with more pointed chin.
• Larger, obtuse vertical forehead angle of the jaw.
• Sharp upper margins of the eye orbits.

                                                                                                  

 As you can see below, here are two gorgeous looking models! Apart from their teeth being shiny bright white, it can be seen that the male teeth is slightly larger than the female’s teeth. In most cases, generally the males teeth are larger than the females teeth!

However do take note that there could be variations at times

 

 Next up, let's look at the palate of the skull (the roof of the mouth). The male has a larger size of palate compared to female. *An easy way to remember this is that, generally males eat more than woman, hence the larger palate!

 

And below , is an image of the zygomatic arch of both males and females, and you may find a difference in the zygomatic arch (cheek bone). As in many examples, the male is in domination again. The zygomatic arch is wider in males and narrower in females.

 

 Contour of the face is another distinct feature whereby the males have skull which is longer and the chin is bigger and protrudes more forwards, the skull is rugged due to its muscular make up, and the zygomatic bones are also more massive. While in females, the skull is rounded with the facial bones being more smoother, with jaws mandible and the maxilla being smaller! Which makes sense, as girls usually have a smaller body frame compared to males!

Picture below shows the side by side comparison of males and female skull and contour of face.

 A&B ( males) while C&D (females)

 

Below is a table, which we have compiled for easier comparison and reference between the difference of male and females in terms of the dental aspect.  

Aspects                                   Male skull                                            Female skull

Weight                                    Heavier                                                Lighter

Size                                         Larger than female                              Smaller than male

Thickness                               Thicker                                                Thinner

Forehead                                 Slightly sloping                                   Vertical

Vault of the Skull                   Vault is more rounded                        Vault is flatter

Supraorbital margin                More rounded                                     Sharp

Mastoid process                      Large                                                  Small

Tympanic plate                       Large & margins more rounded         Small & margins less rounded

With that, we hope that it is now much clearer to identify the differences between a male and a female in terms of the dental aspect in forensic dentistry! :)

References

1) http://www.forensic-dentistry.info/wp/

2)Fehrenbach, Margaret J. 2011. 3rd ed. Ilustrated Dental Embryology, Histology, and Anatomy.