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Installing the SG attachment on a distal extension |
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The SG Patrix is waxed onto the copings with the VKS
Paralleling Mandrel. The use of a surveyor to parallel
the patrices is necessary. It is recommended to use a
lingual support arm with a positive rest. The square
backing of the patrix serves as a path of insertion but
can be reduced in height and width. Take care not to
lose the positive seat on the flat side of the
attachments. |
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The short part of the patrix needs to be placed towards
the tissue (see diagram on right). The patrix should be
placed as close to the tissue as possible without
interfering with the interproximal. Placing the
attachment low on the tooth or bar improves stability
and places less stress on the teeth and implants. |
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After casting and fitting on the model, polish the
attachment lightly. If the attachment is not polished,
residue and oxide may wear the matrices prematurely.
Caution should be taken while finishing and polishing
the subframe. The attachment ball should not be ground
upon or highly polished as it would lose retention and
damage the attachment. |
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To create the overcasting, the model needs to be
duplicated with the yellow matrix in place. The yellow
matrix, therefore, basically acts as a duplicating jig
but is removed and can be reused at a later date. It is
extremely important that all the matrices are placed
parallel to each other to create a singular
insertion/removal path. All undercuts of the frame and
matrix need to be blocked out and absolutely no wax
should be on the matrix when it is duplicated. |
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This shows the refractory model of the case. The
refractory model is basically a duplicate model made in
investment material. Notice the refractory "dummy" of
the yellow matrix. It is imperative not to scratch or
damage the matrix or any of the areas that will be waxed
over. |
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After the refractory model is created, the chrome cobalt
overframe is simply waxed as required. Waxing over the
refractory matrix will create the housing for the
attachment matrices. A lingual arm should be
incorporated into the framework for partials. Bredent
retention crystals or beads could be placed on the wax
framework to create a more retentive surface for the
acrylic. Once spread, the entire model & wax-up is
invested. |
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The framework is then cast and fitted. A light deplating
of the chrome cobalt framework casting is usually
required to clean and polish the interior of the
attachment metal housing. If a higher electro-polish of
the framework is required, it is necessary to block out
the housing interior with a drop of wax to prevent
overpolishing. Overpolishing could result in loss of
friction. |
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To place the matrix into the framework, simply use the
insertion pin and push the matrix into place. Because
the attachments are completely mechanical, no acrylic is
required to hold the matrix in place. To change the
friction of the attachment, a small bur is used to tear
the old matrix out of the housing and the new matrix is
placed as usual. When replacing a matrix, it is
suggested to replace the old matrix with a matrix of the
same color/friction. If an adequate retention is still
not achieved, then the next higher friction matrix
should be used. As with all attachments, the patients
need to know that the appliance should not be inserted
by biting into place - it needs to be inserted via hand
pressure. Biting any attachment into place causes
extreme forces that wear down the attachment
prematurely. |
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Using the SG/SV patrix |
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The SG Patrix is waxed onto the copings with the VKS
Paralleling Mandrel. The use of a surveyor to parallel
the patrices is necessary. It is recommended to use a
lingual support arm with a positive rest. The square
backing of the patrix serves as a path of insertion but
can be reduced in height and width. Take care not to
lose the positive seat on the flat side of the
attachments. |
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After casting and fitting, polishing the attachment
lightly. This is an extremely aesthetic solution as
there is no metal showing from lingual arms or rests and
the crowns can be built up fully with procelain. |
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To create the overcasting, the yellow matrix must be
placed on the ball. It is extremely important that all
the matrices are placed parallel to each other and to
the grooves of the patrix. |
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All undercuts of the frame and matrix need to be blocked
out and absolutely no wax should be on the matrix when
it is duplicated. After duplication, the yellow matrix
is removed and salvaged. |
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The refractory model is basically a duplicate model made
in investment material. Notice the refractory "dummy" of
the yellow matrix. It is imperative not to scratch or
damage the matrix, grooves or any of the areas that will
be waxed over. |
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The chrome cobalt overframe is waxed as required. Waxing
over the refractory matrix will create the housing for
the attachment matrices. For the SG-SV attachment, the
framework waxup must cover the vertical grooves. The
entire model & wax-up is then invested. |
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The framework is then cast and fitted. A light deplating
of the chrome cobalt framework casting is usually
required to clean and polish the interior of the
attachment metal housing. If a higher electro-polish of
the framework is required, it is necessary to block out
the housing interior with a drop of wax to prevent
overpolishing. |
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To place the matrix into the framework, simply use the
insertion pin and push the matrix into place. No acrylic
is required to hold the matrix in place. Notice how the
partial framework wraps around into the grooves. This
provides precision and stability that makes the SG-SV
attachment extremely suitable for uni-lateral cases. |
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Installing the SG attachment on the side of a bar |
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The SG Patrix is waxed onto the copings with the VKS
Paralleling Mandrel. The use of a surveyor to parallel
the patrices is necessary. It is recommended to use a
lingual support arm with a positive rest. The square
backing of the patrix serves as a path of insertion but
can be reduced in height and width. Take care not to
lose the positive seat on the flat side of the
attachments. |
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A hole is drilled into the wax bar using a #8 burr. The
lower to the tissue the attachment is placed, the more
stable the restoration will be. |
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The VKS-Universal patrix is placed into the mandrel as
shown. The mandrel is required to keep the attachments
parallel to each other and to the wax bar. |
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The round backing of the universal patrix is inserted
into the hole in the bar and is fixed with wax. The
backing should be flush with the bar so that the
attachment is not recessed or overextended on the bar. |
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This shows the bar with the patrix. The SG Patrix can
also be used on the bar by simply reducing the concavity
on the backing and waxing it directly onto the side of
the bar. |
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After casting and fitting, polish the attachment
lightly. If the attachment is not polished, residue and
oxide may wear the matrices prematurely. The attachment
ball should not be ground upon or highly polished as it
would lose retention and damage the attachment. |
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To create the overcasting, the yellow matrix must be
placed on the ball. The yellow matrix basically acts as
a duplicating jig but is removed and can be used as a
medium friction matrix later. It is extremely important
that all the matrices are placed parallel to each other. |
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All undercuts of the frame and matrix need to be blocked
out and absolutely no wax should be on the matrix when
it is duplicated. |
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 |
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This shows the refractory model of the case. The
refractory model is basically a duplicate model made in
investment material. Notice the refractory "dummy" of
the yellow matrix. It is imperative not to scratch or
damage the matrix or any of the areas that will be waxed
over. |
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|
|
|
|
 |
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After the refractory model is created, the chrome cobalt
overframe is simply waxed as required. Waxing over the
refractory matrix will create the housing for the
attachment matrices. Bredent retention crystals or beads
could be placed on the wax framework to create a more
retentive surface for the acrylic. Once spread, the
entire model & wax-up is invested. |
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 |
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The framework is then cast and fitted. A light deplating
of the chrome cobalt framework casting is usually
required to clean and polish the interior of the
attachment metal housing. If a higher electro-polish of
the framework is required, it is necessary to block out
the housing interior with a drop of wax to prevent
overpolishing. Overpolishing could result in loss of
friction. |
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To place the matrix into the framework, simply use the
insertion pin and push the matrix into place. No acrylic
is required to hold the matrix in place. To change the
friction of the attachment, a small bur is used to tear
the old matrix out of the housing and the new matrix is
placed as usual. |
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Using the SG Bar Patrix |
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The SG Patrix is waxed onto the copings with the VKS
Paralleling Mandrel. The use of a surveyor to parallel
the patrices is necessary. It is recommended to use a
lingual support arm with a positive rest. The square
backing of the patrix serves as a path of insertion but
can be reduced in height and width. Take care not to
lose the positive seat on the flat side of the
attachments. |
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Any remaining sections of the bar can be saved to be
used at a later date. The bar is paralleled onto the
implant abutments or crowns using any bar mandrel and
waxed into place. The bredent bar mandrel (430 062 30)
is ideal. |
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Since the patrices are already parallel on the bar,
there is no need to use the VKS paralleling mandrel. The
case is cast, duplicated and finished according to
figures 6-12 of "instructions for the side of a bar"
above. |
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All
measurements are in millimeters.
