This method is used a lot by manufactures, because of it's ability to make more than one. A mold of the sculpture is made first. Once the mold is created you can make as many sculpts as you want. A liquid, such as epoxy, clay, plaster, or concrete, is poured into the mold and allowed to harden. Once the liquid hardens the solid form is broken out of the mold. This is seen quite a bit in Pottery Stores. A solid form of liquid plaster is known as green-ware.
In these pictures, the sculpture of the teeth were formed by pouring the liquid plaster into a mold made from the patient's mouth.
