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Research Associate

Saturday: September 10, 2011

I have not truly begun my duties as an RA yet but I have been shown the ropes and began practicing. The process can be simplified as thus:

Researchers from around the globe take molds of molars in their samples and send them to us. I have been given a site from Isreal to work with first, since I am expected to present at the Biological and Forensic Anthropology Association (BARFAA) in October. The first step is to clean the molds with alcohol because sometimes the dirt from a tooth is left in them.

Then, I mix up resin and hardener to cast the teeth. The cast works better to reflect the light from the white light confocal profiler (WLCP) than real teeth, and it standardizes all the teeth samples for comparisons. Not to mention, it also prevents us from having the full responsibility of samples in house and opens up a lot more sites to be studied (some of which may be reburied right away can still have the teeth examined through the casts).

I carefully adjust the tooth on a tray so that Phase II is level. Phase II can be thought of as the part on top of your molar that can be felt with your tongue and hikes up to your cheek (of course, it is much more specific than that). Phase II is useful for dental microwear because it is where food hits the tooth during chewing. Microwear, by the way, refers to the scratches and pits that you (yes you!) have on your teeth that can only be seen via a microscope. Different diets will show different patterns of wear. In older populations, some of the teeth are completely worn down and are flat across the top, even exposing the dentin inside. Although this does not bode well for my particular kind of study, it is a fascinating thing to witness. Teeth were used as major tools back then, but also food processing did little to soften food as we have now. In fact, sometimes stoney grit was added to food as a consequence for grinding it with stone tools. In fact further, some populations today still wear their teeth down!

Next, I use the microscope to find a representational place on Phase II and then use the software that came with the WLCP to profile the texture of the tooth. The light shines down and bounces back to the lens and this is calculated so that it can be represented through computer output, rendered in several ways. First, it shows as a gradient of elevation. I then show it as a true image which can give the appearance of an Scanning Electron Microscope image (SEM). This is important because our technology is new and therefore we need to make sure that our results are comparable to SEM results for a control factor, but also because SEM images are what everyone is already familiar with.

Here, I will inspect the image for evidence of dirt. At this point, it will be microscopic dirt, and likely part of the cast so instead of removing it in real life which is likely impossible, I can edit the images so the program understands that it should not be included in the calculations.

Amidst all the linear scratches or circular pitting, you may wonder how I can identify dirt, but the trick is that dirt generally looks like tiny little balls, unlike anything else on the tooth surface so really it is not that difficult to determine. I use the program to erase little spots and then tell it to finish with the calculations.

There is more after this step, but at this point, I am just focusing on finding Phase II (it is not that easy for a newb like me since I am still learning simply how to identify which tooth is which) I also poke around learning the program (and earned the title Rebecca the Grey which quickly transformed into Rebecca the White and even sometimes all the way elevated to Gandolf since I happen to have magic computer powers). I should start on the real thing in the coming week and my next post about it hopefully will include some sort of visual reference for you.

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One remark!

  1. You are not a newb…sounds interesting so far. – I could clean up the mold…maybe mix the risen but to learn what tooth is who forget me.
    You have one over the rest – you know your computer skills. good for you. what comes next
    Take time to relax, eat, and get sleep. enjoy as well as learn is the name of the game. Keep going a tooth at a time.

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