This document discusses procedures for boxing master impressions and making master casts. It describes two methods for boxing maxillary impressions using either pumice and plaster or wax rods and strips. For mandibular impressions, a layer of adhesive or wax is applied to the impression border before adding a wax land and boxing wax enclosure. Master casts are poured in stone, trimmed with a 4-6mm peripheral roll and notches added for remounting. Landmarks like the incisive papilla and retromolar pad midpoint are marked on casts.

1. Boxing Impressions and Making Casts
John Beumer III, DDS, MS
and
Robert Duell, DDS
Division of Advanced Prosthodontics
UCLA School of Dentistry
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2. Procedures
 Box impressions
 Pour master casts in stone
 Trim and index cast

3. Boxing Master Impressions and
Making Master Casts
• Purpose - Fabricate a cast that
• Preserves the peripheral role
• Provides a protective rim around the cast
(land). This rim (land) must be 4-6 mm
wide.
• Produce a dense cast of vacuum mixed
stone of the proper dimension (10- 15 mm
thick) to permit flasking.

4. Boxing the Maxillary Master Impression
Two methods
• Pumice and plaster method
• Bead and box with wax rods and
sheet strips

5. Boxing - Beading and Boxing with Wax
Maxillary impression
1) Apply a layer of sticky wax around the the
impression 3 mm below the periphery as
shown.

6. Boxing – Beading and Boxing with Wax
2) Apply and seal
rods of beading wax
to the sticky wax on
the impression to form
the land.

7. Boxing – Beading and Boxing with Wax
3) Wrap a sheet of red boxing wax around the beading
wax to form a container. All joints must be sealed with hot
wax to prevent stone from leaking through.

8. Boxing -Plaster and Pumice Method
1) Draw a line around the impression 3
mm up from the periphery.
2) Set impression in a 1:1 mixture of
plaster and pumice.
3) Push impression halfway into the
mix.
4) Push the mix up around the
impression with a spatula to create
a land at the level of the line drawn
on the impression.
5) When the mix is set, trim on the
model trimmer to create a 4-6 mm
land.

9. Boxing – Plaster Pumice Method
6) Wrap the impression in sheet wax
and seal it to the plaster pumice
boxing with hot wax
7) Brush a light layer of vaseline onto
the plaster land area so that the
stone of the cast does not stick to
the land
8) The container made from the wax
sheet must be at least one half
inch above the highest point of the
impression to create an adequate
base to the cast.

10. Pouring the Cast
Prepare a dense mix of yellow stone using your vacuum
mixer and vibrate the stone into the boxed impression. Be
careful to avoid entrapment of air bubbles.

11. Boxing the Mandibular Impression
 Apply a layer of rubber base adhesive or hot
sticky wax to the impression as shown.
 This layer should about 3 mm above the
height of the border of the impression.

12. Boxing the Impression
•Apply a strip of red beading wax to the sticky wax layer to
form the land of the cast.
•Close the lingual tongue area of the impression with a
sheet of wax or with pumice and plaster.

13. Boxing the Impression
•Wrap a layer of boxing wax around the impression to
form a wax container.
•All joints must be sealed to prevent seepage of stone
into undesirable areas

14. Boxing the Impression
The same result can be
achieved by boxing the
entire impression with a
mixture of plaster and
pumice (to form the land
area) and boxing wax to
create the enclosure.
If you use this method be sure to coat the plaster pumice
mixture with vaseline before you pour stone into
impression so that cast will separate from this mixture.

15. Pouring the Cast
Before you pour the cast
make sure the boxing is
sufficient to permit the
fabrication of a cast at
least 10 mm thick.
thick
•Vacuum mix the yellow stone
•Carefully vibrate the stone into the impression.
Start on the buccal of one side and progress to
other side.

16. Remove the Cast from the Impression:
• Wait 1 hour for the stone to set
• Immerse the cast-impression into hot water for 5 minutes
to soften the compound border molding before separating
the cast from the impression.

17. Retrieving the Cast
After heating the compound in a water bath, carefully
separate the cast from the impression

18. Trimming the Cast
• With a model trimmer flatten
the base so that the base is
parallel to the ridge. The
cast should be ½ inch thick.
• Trim the sides of the cast so
that there is an even 4-6
mm of land around the cast.
• Trim the land with a burr or
sharp knife and reduce so
that the depth of the
peripheral roll is 2-3 mm
throughout.

19. Trimming the Master Cast
Trim master casts.
The base should be no
thicker than 15-20 mm.
If the base is too thick the
cast will not fit within the
confines of the denture flask.
The land of the cast must
be at the same level as the
edge of the lower member of
the flask.

20. Completed Master Cast
Land
(4-6mm Depth of peripheral
thick) roll (2-3 mm)
Base (15-20 mm thick)

21. Trimming the Master Cast
The base for this cast was insufficient and eventually it
fractured necessitating remaking of the impression

22. Master Casts
These casts have
been properly
trimmed and marked.
Place rounded notches (arrows)
on the bottom of the master cast.
These notches will later be used to
remount the processed denture
back onto the articulator.
The notches should be placed on the back and on the sides of the casts.

23. Cast Landmarks - Maxilla
Anterior land
Incisive
papilla
Midline

24. Cast Landmarks -Mandible
Midpoint of
retromolar pad
Mark on land
Land
indicating the
Lines indicating the midpoint of the
crest of the ridge retromolar pad

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