BEADING &
BOXING
DR V GAUTHAM
If you don't capture the information from your
impression, then your impression is worthless. The
borders of the impression are especially important.
BEADING
• The purpose of beading is to provide the master cast
with a land area (which should outline and preserve
the peripheral roll).
• The land area serves to delineate and preserves the
useful limits of the impression.
• This is done by incorporating a right angle (which does
not exist in the mouth) in the master cast..
The beading wax is made perpendicular to the
impression, which results in a little shelf completely
around the impression
TECHNIQUE
• Carefully lute some utility wax strips( beading wax)
completely around the periphery of both the
maxillary and mandibular impressions.
• The wax strips must follow the borders (3mm below
the height of contour) of the impression, dipping with
the muscle attachments and rising with the
mucobuccal and mucolingual folds.
• It is this horizontal component of the wax strip that is
visible when viewing from the tissue surface of the
impression that will form the land area.
• Your ultimate purpose is to capture the shape of the
muco-buccal and muco-lingual sulcus in the model.
• The beading wax should act as a spacer between the
impression and the boxing wax.
PROBLEM AREAS
• Retromolar area (mandibular) – may follows the
contours of the impression but fail to keep wax
horizontal.
• The end result is little or no land area. Add an extra
thickness of beading wax in the retromolar area.
• Since the land area should be 2-3mm wide make the
beading wax 4-5mm wide. This will allow for
trimming of the cast.
BOXING-IN THE IMPRESSION
Boxing in an impression is the process of building up
of vertical walls, usually in wax developing around
the final impression for complete dentures to
produce the desired size and form of the base
of the cast, and to preserve certain landmarks of
the impressions.
BOXING
• The purpose of the boxing is to provide a proper size
base without inverting the impression.
• The minimal height of the base is 1/2in (13-15mm).
• The thinnest points of the base are most likely at the
lingual flange or the highest point on the palate. Always
make the stone base a little thicker, and then cut it down.
• (It is a good idea to position the impression so that the
ridge is parallel to the bench top. Then the eventual base
will be parallel to the ridge crest.)
• The boxing wax should never touch the impression. It
should stand away at least 3mm, preferably 5mm. The
beading wax should be wide enough to provide this
space.
ADVANTAGES OF BOXING –IN
1- the correct width and extension of the periphery of the
impression is preserved.
2-the mixed stone can be vibrated, the cast will not
contain air bubbles and a stronger cast will be
produced.
3- the thickness of the cast may be more
accurately judged.
4- boxing-in is time saving, because trimming may be
not be required.
5- material is economized.
Technique
• The vertical walls of the boxing are made of sheets of
beeswax.(modelling wax)
• The tongue space in the lower impression is made with
a sheet of beeswax that is fitted and attached on the
superior surface of the beading wax.
• And located just below the lingual border.
• Boxing wax is attached around the outside of the
beading strip so as not to alter the borders of the
impression.
• It should extend 13 to 15mm above the impression so the
base of the cast at its narrowest point will be of this
thickness.
• the sheet of boxing wax should extend completely
around the impression and be sealed to the beading
wax strip to prevent the escape of stone when this is
poured in to the impression.
• Sufficient space must be available posteriorly between
the impression and boxing to provide for adequate
thickness of casts distal to the impression.
POURING THE CAST
• A stone is mixed carefully and vibrated, and
then sufficient stone is poured in to the boxed
impression that the base of the cast will be 13 to
15mm thick.
• The stone is allowed to harden for at least 30
minutes before impression.
REMOVING THE CAST
• After the stone/plaster is hard, peel off the wax.
• Place the model and the tray in warm water so as to soften the
compound. Don't heat the compound too much, or it will get
sticky. Gently pry the tray off the model after the compound
softens.
• Never put a dry model in boiling water. The heat will cause the
air trapped in the stone to rapidly expand and crack the model.
• Remember that stone is soluble in water. Letting water drip on a
model for ten minutes will visibly alter its surface.
ADVANTAGES OF BOXING –IN
1- The correct width of the periphery of the impression
is preserved.
2-the mixed stone can be vibrated, the cast will not
contain air bubbles and a stronger cast will be
produced.
3- the thickness of the cast may be more
accurately judged.
4- boxing-in is time saving, because trimming may t be
not be required.
5- material is economized.
QUESTIONS
1) BEADING WAX SHOULD BE APPROXIMATELY-----MM WIDE.
2) THE BOXING WAX SHOULD BE AT LEAST ----MM MEASURED
VERTICALLY FROM THE HIGHEST POINT OF IMPRESSION.
3) THE BEADING WAX SHOULD BE PLACED -------MM BELOW THE
HEIGHT OF CONTOUR OF IMPRESSION FLANGES.
4) PUMICE AND PLASTER BOXING IS INDICATED FOR -------TYPE
OF IMPRESSION.
5) BEADING IS DONE TO PRESERVE -----------OF SULCUS IN THE
CAST.
6) ---------IS DONE TO OBTAIN UNIFORM , WELL SHAPED ,
SMOOTH BASE FOR CAST.