Abstract
Several newly available plastics become malleable when immersed in warm water or subjected to warm air; they return to a more rigid state when cool. Because fabrication requires that they be heated only to temperatures tolerated by the skin, one can mould them directly on the patient to produce custom-designed and individually-fitted devices, The new thermoplastics are modified readily upon reheating with warm water or air. Although varying in colour and texture, these materials all present a comparatively pleasing appearance. As a group, however, they are less rigid and less durable than other plastics or metals used in prosthetics and orthotics. While the initial cost of the new thermoplastics exceeds that of other materials, the finished appliance generally is less expensive because less time, skill, and equipment are needed for fabrication. Each plastic is analyzed in terms of its chemical and physical characteristics; commercial forms, whether marketed in sheet, tape, or precut splint form; and fabrication requirements. Although their principal use is in upper-limb orthotics, especially hand and forearm appliances, these plastics are suitable for selected application in spinal orthotics, such as collars and body jackets; lower-limb orthotics, particularly shoe inserts; and for the sockets of temporary prostheses.