Setting temperatures of plaster casts. The influence of technical variables.

It is known that plaster-of-Paris casts can cause burns. Experiments were done to determine what factors are involved in causing an elevation of the temperature in a freshly applied cast. A glass tube filled with water between the temperatures of 36 and 39 degrees Celsius was used to simulate a leg for this study. Standard plaster casts were applied to the tube and the following variables were studied: different temperatures of the dip water; different thicknesses of the cast; the presence of plaster residue in the dip water; and the effect of the plaster of a pillow placed under the tube. It was found that if the temperature of the dip water was higher than 24 degrees Celsius or the thickness of the cast was greater than eight ply, or both, and if the pillow was used to limit the dissipation of heat from the cast, temperatures high enough to cause skin burns could occasionally be reached. Variable results indicated that these were the factors operating in practice and that a combination of them posed the greatest hazard.