Introduction: Cast Your Teeth for Halloween

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Dental casting is super fun, and way easier than it seems.  Halloween is the perfect reason to make a cast of your teeth to sculpt custom fake teeth on top of them (as if you needed a reason)! 

If you can't get your supplies locally, there are lots of places to look on the internet.  I went directly to one of my favorite companies, Monster Makers.  They sell everything you need, plus videos, to show you how to make awesome, gnarly teeth (and a bunch of other cool stuff).

But before you can make your fake teeth, you have to cast your real teeth!  This Instructable is going to show you how to make a professional grade mold of your teeth, just like a dentist would.

Step 1: Materials

This is what came in my awesome Monster Makers kit:
  • Dental Trays
  • Dental Alginate
  • Tongue depressors
  • Ultra Cal 30 Gyspsum Cement
  • Mixing Bowl
  • Rubber Base Form
  • Some cool stuff to make teeth that we'll get into in another Instructable

You'll need to supply your own:
  • Cups
  • Water
  • Latex gloves
  • Paper towels
  • Teeth

Step 2: Making the Impression

We're going to use the alginate to take an impression.  This kit came with dental grade alginate, which has a very refreshing minty flavor.

Make the impressions one tray at a time.  They only take about a minute to set up, so there's really no point in trying to do both at once and risking failure due to uncontrollable gagging.  Just trust me on this.

For one tray, you'll want to mix up:
  • Two tablespoons of alginate with
  • Two tablespoons of room temperature water
The temperature of the water will determine how quickly the alginate sets.  The warmer the water, the faster it sets.  Room-temperature water is perfect, even for beginners.  This gives you about 30 seconds to mix, and 1 minute to set.

Mix the alginate well.  It will have the consistency of cake frosting.  Fill the upper tray with alginate and fit into the mouth so that the teeth float in it, and don't touch the edges.  Make sure to get the upper lip out of the way so the alginate can take a full impressions of the gums as well.  This took me about three tries to figure out.

You can tell when the alginate is set by looking at what's remaining in the bowl.  Once it's set, it's pretty likely that what's in your mouth has set.  Since the alginate takes an exact impression, it creates a vacuum when trying to take it out.  Just press on the edges and wiggle it to break the seal.

Repeat on the lower teeth.  Make sure you (or your subject) lean forward while taking the lower impression so no excess alginate can flow out of the tray into the mouth and throat.

** If you're someone with a sensitive gag reflex, remember to breathe through your nose, and hold a paper towel to your mouth to absorb the saliva.  Taking the lower impression made me slobber like a dog for some reason.  This isn't really good 'first date night' kind of 'fun thing to do together' material.

Step 3: Casting the Positive

Since alginate shrinks quickly, it's important to cast the positive immediately. 

To cast both the top and bottom molds simultaneously use:
  • 2 tablespoons water
  • 5 tablespoons UltraCal
You may need to adjust this ratio depending on your climate.  Stir for about 3 minutes until its consistency resembles pea soup.

Tap the cup repeatedly to release any trapped air. 

Use a brush or tongue depressor to tap some of the UltraCal into the molds, making sure to avoid air bubbles.  Tap the molds slightly to remove air before continuing to fill.

After about an hour, the positives can be demolded.  First, remove any excess alginate and UltraCal from around the form.  Then, be careful to remove the cast.  The lower teeth are fragile because they don't include the palette, so be gentle.

Check for faults.  My first casts proved to be too shallow, so it was back to the beginning for me.  The second casts came out almost flawlessly.

Step 4: Casting the Base Form

Now we want to create a permanent base for the teeth, so they'll be stronger and easier to handle.  We'll use the UltraCal again for this.  (I had to go out and get a new bag because I mixed up way too much the first time I cast my positives.  Good thing it's so cheap!

You want the UltraCal for the base to be thicker so the positives can float on top of it.

Soak the teeth form in water for a few minutes so they won't absorb extra moisture from the bases.  Remove from water after a minute and towel off.

To cast one base (since it only came with one) mix:
  • 3 tablespoons water
  • 6 tablespoons UltraCal
Smooth the mixture into the base form.  Don't fill the forms entirely.  Tappa tappa tappa - tap that form for a good minute to get out all the air bubbles. 

Position the teeth form on top of the UltraCal base.  It should make nice contact with the base without sinking in.

Allow the UltraCal to sit undisturbed for one hour.

Peel the casting out of the mold.  Check for defects.  Use a small sculpting tool if necessary to remove any excess stone from the teeth.  Use a small, firm bristle brush to remove any dust.

Repeat with the lower teeth.

You're done!  Don't they look awesome??  Now go cast some awesome crazy teeth on them!  Or just keep them on your desk at work to freak people out.  Carry them around with you and make them talk.  Hold them up to your own teeth and ask people to contrast and compare.  There are no limits to what you can do with your own set of stunt double teeth.