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58 MECHANICAL DENTISTRY AND METALLURGY.

be about the consistency of thin cream. A strip of pink
rubber large enough to cover this whole surface should be
softened over boiling water and pressed. tightly against the
red rubber plate, care being taken to force it well in between
the teeth, using a smooth, clean instrument for the purpose.

Fig. 29.

To vulcanize this it is not necessary to flask the denture in
the usual manner. Wet the plate and place plaster-of-
Paris in the palatal surface; fill the flask with plaster and
embed the denture in it, and place the lid on. When the
plaster is hard, introduce the bolts, and vulcanize thirty-five
minutes at 320° F. After cooling remove the flask and
carefully separate the plaster from the denture. The plate
should be trimmed and polished in the usual way. When

Fig. 30.

polished and thoroughly cleaned the pink rubber may be
bleached, and thus rendered brighter, by placing the den-
ture in the sun in a covered glass vessel partially filled with
alcohol. All trimming should be completed before bleach-
ing, as only the surface of the rubber is changed in color.
Fig. 30 shows the finished case.
Gold Backing and Tongue.—In partial cases where the
bite is so close that the antagonizing teeth come so near