History of Plaster of Paris immobilization OrtthoHeal May 6, 2017 N ow a days it is commonly called as orthopedic cast, body cast, plaster cast, or surgical cast, is a shell, frequently made from plaster, encasing a limb (or, in some cases, large portions of the body) to stabilize and hold anatomical structures, most often a broken bone (or bones), in place until healing is confirmed. Plaster of Paris has been used for centuries to treat fractures by immobilizing bones and allowing undisturbed healing. Plaster bandages consist of a cotton bandage that has been combined with plaster of Paris, which hardens after it has been made wet. Plaster of Paris calcined gypsum (roasted gypsum), ground to a fine powder by milling. When water added, the more soluble form of calcium sulfate returns to the relatively insoluble form, and heat produced. The setting of unmodified plaster starts about 10 minutes after mixing and is complete in about 45 minutes; however, t...