Plaster of Paris, or plaster, is gypsum powder that is mixed with water. This material undergoes an exothermic reaction as its particles join together to form a solid.
When working with this material, some personal protective equipment should be worn: safety glasses, gloves and a dust mask.
Negative casts are molds of a body part or segment. In the field this can be done with either plaster bandage or scotch cast. For the purpose of the orientation week, you will be using pre-modified plastic shells as your negatives for a transtibial (TT) and an ankle foot orthosis (AFO)
With the negative casts, you will be required to make the corresponding positive casts.
Positive casts are a replica of the body part or segment made from plaster. This is done by filling the negative casts with plaster.