FABRICATING TRAYS WITHOUT
Custom trays for complete denture patients are
often made without spacers and adapted directly to the
ridge. If a spacer is not used for tray construction, the
undercuts on the cst must be eliminated very carefully
using baseplate wax. Failing to do so will result in a
damaged cast or tray when you attempt to remove the
Preparing the Cast
First, paint the cast with two layers of tinfoil
substitute to prevent the acrylic resin from sticking.
Next, use baseplate wax to generously block out (fill
in) all undercuts within the tray area outlined on the
cast as shown in figure 8-33(B).
Mixing the Resin
Using premeasured amounts of monomer and
polymer, add the powder to the liquid and mix the
materials. Allow the mix to set until it reaches the
Adapting the Resin
Use a simple stone mold to control the shape and
thickness of the resin dough. This preshaped resin
mass results in a tray of consistent quality when
adapted to the cast.
Lightly coat your fingers with petrolatum before
placing the dough in the stone mold. Be sure the mold
is also coated with petrolatum. Cover the dough with a
moistened polyethylene sheet. Quickly roll out the
resin to match the mold's shape and thickness as shown
in figure 8-34(A). Trim away the excess dough and lift
the acrylic resin blank from the mold.
Center the resin over the cast and rapidly adapt the
dough by hand to the cast's surfaces. Be careful not to
create thin spots by pressing too hard. Shape the resin
to the borders and cut away the excess with a sharp
knife as shown in figure 8-34(B).
Next, attach the handle to the tray, ensure the
handle is strong enough to withstand considerable
force, and that its shape will not interfere with lip
movement. Mix another small amount of tray resin.
When polymerization reaches the dough stage, form it
into an L shape. Use a few drops of monomer to
moisten the attachment site between the handle and the
tray. Press the handle onto the moistened area. The
fluid ;monomer should provide good bonding. If you
work fast enough, you should be able to use the
unpolymerized excess from the first mix for the handle
as shown in figure 8-34(C).
Finishing the Tray
After the acrylic has set, remove the tray from the
cast and remove any wax adhering to the inside of the
tray. Trim the tray's flanges back to the peripheral
Figure 8-34.Fabricating custom trays using the dough method.