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1. In dentistry, a positive copy of jaw tissues over which denture bases may be made.
2. To make an accurate metallic reproduction of a wax pattern of a dental appliance, tooth crown, or inlay cavity preparation.
3. Pliable or fibrous material shed in various pathological conditions; the product of effusion. It is molded to the shape of the part in which it has been accumulated. Casts are classified as bronchial, intestinal, nasal, esophageal, renal, tracheal, urethral, and vaginal; constituents are classified as bloody, fatty, fibrinous, granular, hyaline, mucous, and waxy.
4. A solid mold of a part, usually applied in situ for immobilization of fractures, dislocations, and other severe injuries. It is carefully applied to the immobilized part and allowed to dry and harden (over 24 to 48 hr). Care is taken not to apply any pressure to the cast until after the cast is dried and hardened. Synthetic materials, such as fiberglass, are also used, esp. for non-weight-bearing parts of the body.
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Neurovascular status distal to the cast is monitored, and any deterioration in circulation and in sensory or motor abilities, such as paresthesias, paralysis, diminished pulses, pallor, coldness, or pain, is documented and reported. Pain or burning under the cast other than a transient sense of warmth (which is expected) is also documented and reported. The cast may be bivalved or removed to relieve pressure on the swollen tissues beneath it. To limit swelling the casted extremity should be supported above heart level for the first 24 hours. All casts must be kept dry to avoid maceration of the skin. A simple means of doing this is to place a plastic bag over the cast before showering and attach it to the skin with duct tape, then enclose that in a second larger bag and tape that to the skin over the first. Objects should not be placed inside a cast to relieve itching, but relief often can be obtained by applying cold (a well-sealed ice bag) to the cast over the area that itches, or by scratching the opposite extremity in the same area. Joints above and below the cast should be exercised to prevent stiffness and contractures. The patient is instructed in symptoms to be reported, care of the cast, and ways to protect the cast from damage; prescribed exercises or activity limitations; and use of any assistive devices such as slings, crutches, or walker.

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Cast and cast application (ankle fracture)

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