What should you know about dry plaster of paris?

Plaster of Paris is applied as wet layers around a padded body part or over a splint. Water starts a chemical setting process, so the material changes from soft and mouldable to firm. A cast may feel warm while setting. It is shaped to support an injured area, limit unwanted movement, or guide correction; the exact purpose depends on the injury and treatment plan.

[Fracture Casting](/treatments/trauma-and-fracture-care/fracture-casting/) uses casting principles for broken bones, while [Clubfoot Casting](/treatments/reconstructive-orthopedic-surgery/clubfoot-casting/) uses serial casts to gradually guide foot position.

Keep the cast uncovered and supported in the position advised by the care team until it is firm. Do not press dents into it, insert objects underneath, trim edges, or add powder. Keep it dry unless your clinician has given specific waterproofing instructions. Elevate the limb when advised and move the free fingers or toes gently to help monitor swelling.

Do not walk on a leg cast or use an arm cast for lifting until you have been told it can bear that load. Ask how to bathe, sleep, use crutches, and attend follow-up appointments. Read more about the material at [Plaster of Paris](/materials/plaster-of-paris/).

Call the treating service promptly if the cast becomes soaked, cracks, loosens, rubs the skin, or develops a strong odour. Seek urgent care for increasing pain or tightness, numbness, tingling, pale or blue fingers or toes, inability to move them, marked swelling, fever, or shortness of breath. These changes can signal pressure, skin injury, infection, or another problem requiring examination.

How long should this cast remain protected from water and weight? Which movements are safe? How can I check circulation? When is the cast review scheduled, and what should I do if it becomes loose or uncomfortable?