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114 Ol'ERATIVE DENTISTRY

cieiitly hard not to yield under the force necessary to introduce
the pattern wax. It will also prevent the portions of wax from
adhering. The wax for the pattern should then be softened, pref-
erably in warm water. The wax should be sufficiently plastic to
permit of molding when manipulated in the fingers, care being
taken that the wax is not folded upon itself as the portions will not
adhere. Wax so folded is liable to part at the folds and come away
from the cavity in sections. The wax should be gently shaped so
that it can be introduced into the cavity in such manner as to come
in contact with the base walls or floor of the cavity first, then by
slow continued pressure for about fifteen seconds made to expand
till it entirely fills the cavity, overflowing all margins.
If the inlay is to replace any portion of the occluding surface the
operation should be done with the rubber dam off. The patient is
requested to close the teeth to full occlusion, slowly. It must be
remembered that the casting wax is only semi-plastic and moves
very slowly, hence the best impression is obtained by moderate con-
tinued force, giving the sluggish wax time to flow. Wax is really
quite elastic when confined and when the pressure from the bite
is removed will spring back the least bit, so that the cast inlay will
be too high when set.
To overcome this it is good practice to have the patient again close
the teeth to occlusion with one layer of rubber dam over the occlu-
sal surface of the model, requesting him to maintain the pressure
for some seconds. The elasticity of the rubber dam will overcome
the elasticity of the wax. This will do away with much grinding
after fitting the inlay to position. The pattern should then be carved
to full contour restoration and correct external surface form, and
the wax thoroughly burnished around the entire cavity outline.
The carving and burnishing of the wax is materially assisted
if the surface is warmed by the use of warm water. This is best
accomplished by dipping large loosely-rolled cotton balls in water
that is almost too warm for the fingers, carrying it to the mouth
and folding about the wax, allowing it to remain for a few seconds.
Upon removing the cotton the wax will be found to have softened
to a sufficient depth to be easily manipulated. In case the wax does
not quite reach the margin, the same should be crowded over to
the margins, carrying quite a body of the wax over before attempt-
ing to burnish down to the margins. If this is not done the wax
will be found to fit only at the cavo-surface angle, leaving a space
just below this point to which the wax is not adapted.