Science Buddies: "Ask an Expert"

What can I use instead of human teeth to show the effects (decay and discoloration) of beverages such as soda and juice, on teeth?

Hi,

Sorry it has taken so long to get a reply to you. I guess we don’t have many experts on teeth.

Clearly the best item to use is human teeth, like baby teeth that have fallen out. If you can’t locate these, then probably the next best alternative would be animal teeth, such as cow teeth. You might be able to get these from a slaughterhouse, if there is one in your area.

As a last resort you might try chicken bones, like thigh bones.

Teeth are mainly made of calcium phosphate in a material called hydroxyapatite. Bones are mostly made of the same stuff, though with other material mixed in. Teeth are almost pure mineral, bones are only 70-80% mineral.
http://en.wikipedia.org/wiki/Hydroxyapatite


If you expect teeth to dissolve in soft drinks, you should expect bone to turn rubbery and flexible in the same liquids. In both cases the calcium phosphate might dissolve, but in the case of bones the bone structural protein will be left behind as a rubber like shape.

Hope this helps a little! Good luck on the prohect.

Barrett Tomlinson

Hi there,

I just wanted to add that as a very final resort you could always put an egg in a jar, cover it with vinegar, screw the lid back on and leave it for a few days (you can also put an egg into fizzy drink i.e. coke, lemonade, etc). I tried this with my Year 2/3 class and was able to explain it best by comparing the layers of an egg to the layers a tooth has- the shell is like the enamel, a suit of armour which protects the tooth nerves and everything else inside. When the egg's outer layer begins to peel/decay in a matter of days, I say that this is what happens to teeth when they are not looked after properly and come into contact with 'bad foods/drinks'. The plaque eats away at the enamel and starts to decay. The tooth no longer has a protective layer so it becomes overly sensitive to hot/cold foods/drinks.
_____________________________________________________________________________________________________________________________________
Also, an interesting spin off to this activity (which I didn't do as I was just starting out teaching at the time trying to keep things more structured) is you can actually remove the eggs from the vinegar and drop them onto the ground...they should bounce!

Hope some of this info helps...I have also attached some info I used

Good Luck!