A bite into the mystery [Questions 1 & 2]

Welcome back our dear readers and budding Detecteeth! ;) Happy Halloween too! 

In this post we are going to solve the questions that were raised previously, so shall we begin?

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?

As the name itself suggests, Forensic Dentistry is the study and practice of aspects of dentistry that are relevant to legal problems (Encyclopaedia Britannica, 2009). The major use of it is to identify and confirm the assailant by comparing the bite mark left on the victim (shown in Figure 1) with the dentition record of the suspect. The simplest way to compare is to check for missing tooth, orientation and alignment of tooth, restoration and shape and size of tooth as no two mouths are the same. This also applies to identical twins as one twin may have a chipped tooth due to environmental factors such as falling down (forensic-medecine.info, 2014).

Figure 1: Bite Mark

Still curious how bite mark identification works? Watch this short but very informative video here! 

For burnt victims, the identification is deemed possible through forensic dentistry even when other methods such as fingerprint can’t be done. This is due to the fact that the tooth is the hardest structure of the human body and it will still be intact even after being burnt (Pramod 2012). The remaining tooth from the victim is the compared with the previous dental records. Dental records, such as radiography and perio charting can be saved in the OpenDent software (shown in Figure 2) as used by the Oral Health Center in IMU. The responsibility of the dentist to chart and record accurately is of utmost important in this part of investigation to identify the burnt victim.

Figure 2: OpenDent Software

In the case of a murder, the victim’s remains might be in fragments like in the case given, where Dr Rudi said only a part of a human skull and some jaw like structure with some teeth are found. The remains are also of several months old, making other means of identification almost impossible. In cases like this, where the teeth are still intact, they can be used to assume and hypothesise the race of the victim. According to Stavrianos, 2008, the cusp of carabelli is found more commonly in Japanese population rather than the Chinese population. Moreover, the age also can be estimated. For younger victims, the number of teeth in the oral cavity and the presence of third molar can be useful.  On top of that, the number of restoration and the placement of restoration can also help in identifying the real victim.

Reference:

Encyclopaedia Britannica, 2009, Encyclopaedia Britannica Online Accessed November 1, 2014. Available at http://www.britannica.com/EBchecked/topic/158069/dentistry.

Forensic-medecine.info, 2014, Forensic Odontology , Accessed November 1, 2014. Available from: http://www.forensic-medecine.info/forensic-odontology.html

Pramod, 2012, Role of forensic odontologist in post mortem person identification. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3612186/

Stavrianos, 2008, Methods for human identification in Forensic Dentistry: A Review. Available from: https://ispub.com/IJFS/4/1/5188

Question 2: 

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

Have you ever encountered an awkward moment where you have to decide whether to address the person as Mister or Miss??

It’s a split-second decision and you want to save yourself the embarrassment of offending the stranger you just met.  

Well, truth be told, we Detecteeth have that dilemma too......

Yet, as you strip away the person’s skin, tissues and muscles to reveal the Skull, a trained forensic anthropologist and forensic odontologist are able to determine the gender of the deceased with just a quick glance!

Let us show you how these amazing specialists work their magic!

To understand the differences between a male and female skull, we must first know about the anatomical landmarks of the skull. Pay attention to those highlighted in green boxes!

Lateral view of a skull.

Posterior view of a skull

First, lets have a look at the gross shape and structure of a male and female skull.

Here, we can see that the cranial vault of the male skull is more rounded compared to the female skull

Also, the female chin is more pointed and has a wider angle of jaw.

Next, we will look at the lateral view of the skulls and compare

As you can see,the slope of the frontal bone of the female skull is more vertical 

(Male skull = Left, Female skull=right)

Besides the more prominent brow ridges in male skull, male skull also has a larger and more pronounced mastoid process compared to a female skull.
The External Occipital Protuberance of the male skull is also more developed compared to a female skull.

Zygomatic bone

The zygomatic bone of a Male skull is more massive compared to a female skull.
The zygomatic arch also extends back and pass the external auditory meatus in male skull.

Another technique is to look at the temporal line of the skull.

A male skull often has a more pronounced ridge than a female skull.

HOWEVER......

Looking at the pictures above, we can see that Britney Spears has very pronounced temporal line. It is practically indistinguishable from the other bald male actor above.
Which brings me to my 

MOST IMPORTANT POINT!!

You shouldn’t rely on one of these features in isolation to determine gender, but should look to a combination of the factors to give you a reliable indicator.

Sure enough, the differences between male and female skulls may be subtle and require a preriod of “calibration” in order to become proficient in seeing the differences. Once this is done, you should have a fairly well-honed ability to determine the sex of an individual from their skull. (http://forensicoutreach.com/4-ways-to-determine-sex-when-all-you-have-is-a-skull/) 

Now its your turn! Which of these skulls belongs to a male skull and why do you say so??

The answer is.....





Left skull   = Male skull
Right skull = Female skull

AMAZING isn't it!?


To provide you with a clearer view, this table summarizes all the differences that we have just identified and some extra points that can further confirm the deceased's gender.

Cranium Feature	Male	Female
Total Skull	Thicker, heavier	Smaller
Cranial vault	More rounded	More flattened
Frontal bone from lateral view	More sloping	More vertical
Supraorbital ridges (Brow ridges)	More prominent	Less prominent that causes the frontal bone to appear smooth and vertical
Mastoid process	Larger and more pronounced	Small
Symphysis and mental  eminence of mandible (chin)	Squarer	Pointed
Jaw angle	Acute	Large, obtuse
Nuchal crest (where neck muscles attach)	More prominent	Less prominent
Superior margin of eye orbit	More blunt edge	Sharper edge
External occipital protuberance	More developed	Less developed
Zygomatic bone	Larger, wider	Smaller, narrower
Zygomatic arch	Extends back and pass the external auditory meatus	Stops before external auditory meatus

Reference:

1. Forensic Outreach, October 8 2012, 4 Ways to Determine Sex (When All You Have is a Skull). Available from: http://forensicoutreach.com/4-ways-to-determine-sex-when-all-you-have-is-a-skull/

2. Smithsonian's The Secret in the Cellar Webcomic,  February 2009 - 2011,  Written in Bone Exhibition. Available from: http://anthropology.si.edu/writteninbone/comic/activity/pdf/Skeleton_male_or_female.pdf