plaster cast vs plaster of Paris

plaster cast

noun
  • A cast made of a stiff material (often plaster of Paris and gauze) in order to immobilize a broken bone for the period of healing. 

  • A copy of a piece of art or other object cast in plaster. 

plaster of Paris

noun
  • A hemihydrate of calcium sulfate, made by calcining gypsum, that hardens when moistened and allowed to dry; used to make casts, molds and sculpture. 

How often have the words plaster cast and plaster of Paris occurred in a corpus of books? (source: Google Ngram Viewer )