September 22, 2010

Be a science detective - test of observation skills #5

This video activity is amazing, BUT ONLY IF you ask someone else to give you a hand.

Why? Because clicking on the link below reveals the answer... before it asks the question.

So it spoils the fun, unless you close your eyes and someone else clicks on the link for you, then clicks to start the video for you.

First, turn on the sound on your computer.

Then find a helper willing to

1. wait for you to close your eyes

2. click on the link below

3. REMAIN SILENT

4. see a YouTube video ready to start

5. click on the arrow to start the video

6. tell you to open your eyes

Ready?

CLOSE YOUR EYES before you ask your helper to click on "amazing test of observation skills."

September 14, 2010

Follow a dentist – a STEM career glimpse










by Minh Tam Dang, DDS (Doctor of Dental Surgery)
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If you like taking care of people, as I do, you might love to be a dentist like me.
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I do a large variety of things at work, including saving teeth and smiles. Like the day a commotion in the waiting room drew me out of my office. Anguished voices talked at the same time.

“Oh, my!”

“He got banged in the mouth."

A teen was pressing a blood-stained tissue on his lips. His father leaned over the receptionist’s counter.

“He broke a tooth right in front.”

I took the wounded boy to the big chair. “Let me look.”

The dental assistant gently rinsed the blood away with a stream of water so I could see. “Only one tooth looks damaged.” It was a top tooth, one of the two middle ones, broken at a slant one third of the way up. “Let’s take an X-ray.”

The dental assistant led the boy to the X-ray cubicle while I walked to my desk to wait for the digital image to appear on my computer screen. I stared at the tooth all over—what was left of it—especially the root, the bone around it, and the middle of the tooth, or pulp chamber, containing the nerve. The break was far enough from the pulp chamber, so there was no need to empty it, then fill it with an artificial material (do a root canal treatment).

Dr. Dang reviewing an X-ray (but not the one in the story)



That was very good news. A live tooth is stronger and sturdier than a dead or fake tooth.

The plan, then, was to cap the broken tooth with a temporary crown and replace it with a permanent crown later.

A crown is hollow, somewhat like a pencil cup. Its outside shape must match the original tooth. Its inside shape must fit the broken tooth—after it’s been prepared by filing it down, to make room for the crown.

First I numbed the tooth and gum with pain killers (anesthetics), by rubbing a numbing gel on the gum, then giving an injection next to the tooth. After a few minutes, I made sure the patient couldn’t feel a thing by testing the gums all around the tooth.

Next, I pictured the prepared tooth in my mind and filed down as needed. The taper and smoothness were very important for the finished product to look good, with no visible line where the crown would meet the natural tooth, just under the gum line. It was like carving a miniature sculpture, except it would not sit in a glass case untouched--it would chomp on food, many times a day for years to come. It would also be seen every time this young man smiled.

I took a mold (impression) of the prepared tooth. I filled a special, small “tray” with a special, soft paste. I squirted softer paste on the tooth to capture the finest details of the edges, so the crown would fit perfectly.

I put the tray in place and asked the patient to bite down. Minutes later, the paste had hardened (set). I took the tray out, sprayed it with disinfectant, and bagged it.

To order the crown, I wrote up the lab slip and asked the lab to make it of porcelain (not porcelain fused to metal or gold). I specified the color closest to that of the other teeth. I held a color chart next to the patient’s teeth and he helped pick the shade.

The lab courier, who comes by every day, picked up the bag and slip. It would take the lab roughly two weeks to make the crown.

Meanwhile, the patient needed a temporary crown. The dental assistant made it, because no pre-made, stock acrylic crown was quite right. She glued it on with temporary cement.

The patient walked out smiling and having silly fun with the numbness, which would disappear within a few hours.

Every team member had to do excellent work to get fine details just right.

As the dentist, I had to prepare the tooth so it would be just the right size and shape. It couldn’t be too thin or it would break. It couldn’t be too thick or else it’s the crown that would be too thin. The filing-down couldn’t come too close to the nerve or the tooth would be sensitive and hurt all the time. The mold could not be distorted, or the crown wouldn’t be the right shape inside and it wouldn’t fit.

The dental assistant faced many similar challenges when putting together a temporary crown.

The lab people used the mold to make a plaster model of the prepared tooth and neighboring teeth, then made a permanent crown on the model. When this crown was ready, it was tried on and final adjustments were made for a perfect fit, before it was cemented in place.

Crowns can last a long time (if their owners take care of their mouths, by brushing twice a day, flossing once a day and seeing a dentist every six months) and that’s something to smile about!

ABOUT MINH TAM DANG

When Tam is not working, she loves arranging flowers, gardening, playing with her two cats (Diddi, also known as “The D,” and Louie), painting with watercolors, quilting, reading and writing Vietnamese poetry, and playing tennis, hiking or riding bikes with family.

LINKS

● Watch this short video overview of dentist careers.

● For a little longer overview of dentist careers, click on “Listen to the podcast…” at the Sloan Career Cornerstone Center. It’s an introduction to the required schooling, a day-in-the-life of a dentist, salary info, specialties, and the great job market in the years ahead.

● For dentist interviews, click on the names below.

Jennifer Cyriaque

James Tynecki

Stephen Sterlitz

● Watch this 25-minute award-winning career video about “Women in Dental Research.” After a brief history of dentistry, it follows three amazing women. One fought the AIDS epidemic, the second one, a molecular researcher, studies oral disease and cancer, and the third one leads researchers who provide free dental care to children.

September 7, 2010

Real world math

Watch fun videos on The Futures Channel about all kinds of careers that use math, such as architect, bat scientist, bike designer, exotic animals manager, undersea treasure hunter, and more.