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Which type of plaster
should be used to fabricate the models?
What kind of preparation requirements
must the die demonstrate in order to produce accurately fitting restorations?
Can
an incisal edge, which has become too thin during preparation, be adjusted
prior to scanning to avoid complicating
the try-in procedure after machining?
Should manual adjustments with grinding
instruments be done before or after the crystallization process?
Can machined
IPS e.max CAD restorations in the precrystallized (blue) state be completely
finished and then crystallized and veneered?
Do IPS e.max CAD restorations
shrink during crystallization?
Why does the IPS Object Fix paste have
to be used during the cyrstallization process?
Can firing pastes other
than IPS Object Fix be used in the crystallization process?
Can other
firing trays, eg "honeycomb" trays,
be used for the crystallization of IPS e.max CAD?
Can furnaces other than
those from Ivoclar Vivadent be used to crystallize IPS e.max CAD restorations?
Can
the crystallization quality of IPS e.max CAD restorations be controlled?
Can
IPS e.max Ceram Margin materials be used with IPS e.max CAD?
Can IPS Empress
Universal Shades, Stains and Glaze be used on IPS e.max CAD?
Can IPS e.max
CAD frameworks be blasted with Al2O3 or glass polishing beads before
they are veneered or
after their completion (on the cavity side)?
How must the internal (bonding)
surface of IPS e.max CAD restorations be conditioned before cementation?
Can
IPS e.max CAD restorations be conventionally cemented?
Which type of plaster should be used to fabricate the models?
The instructions of the manufacturer of the CAD/CAM system in use should
be observed in the fabrication of the models. The following
basic rule applies: Depending on the CAD/CAM system and equipment, special
plasters may have to be used for the fabrication
of models and dies to ensure the quality of the scan. If a special scanning
plaster is unavailable, models and dies can be fabricated
with high-strength stone, which is sprayed with IPS Contrast Spray immediately
before the scanning procedure. (
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What kind of preparation requirements must the die demonstrate in order
to produce accurately fitting restorations?
The traditional preparation guidelines for all-ceramic restorations apply
to IPS e.max CAD. The thickness of the incisal edge of
prepared anterior teeth requires special attention. The prepared incisal
edge should be at least as thick as the diameter of the bur
used in the cavity. The corresponding instructions of the manufacturer
regarding the dimensions of the grinding instruments must
be observed during preparation. (
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Can an incisal edge, which has become too thin during preparation, be
adjusted prior to scanning to avoid complicating
the try-in procedure
after machining?
In cases such as these, we recommend blocking out the incisal edge of
the prepared die until the thickness matches that of the bur.
These areas will be filled with luting cement when the restoration is
seated. (
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Should manual adjustments with grinding instruments be done before or
after the crystallization process?
All grinding adjustments of milled IPS e.max CAD restorations should
be made in the precrystallized (blue) state. It is important to
note that the framework in its precrystallized state should be ground
only with suitable grinding instruments at low rpms and light
pressure to prevent chipping, particularly at the margins. (
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Can machined IPS e.max CAD restorations in the precrystallized (blue)
state be completely finished and then crystallized and veneered?
Milled IPS e.max CAD restorations can be tried in on the die and all
areas fully finished in the precrystallized (blue) state. Special
attention must be paid to the restoration margins in this state. The
margins should be created in relation to the preparation and the
thickness of the restoration. Margins that are too thin are not suitable
for crystallization, as these areas are rounded during this
process and therefore shortened. In these cases, the margins should be
thinned out after the crystallization process. (
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Do IPS e.max CAD restorations shrink during crystallization?
During the crystallization process, the microstructure becomes transformed
and densification of 0.2% takes place. The milling software
takes this densification factor into account. Therefore, the milled IPS
e.max CAD restorations demonstrate precision fit after cyrstallization. (
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Why does the IPS Object Fix paste have to be used during the cyrstallization
process?
IPS e.max CAD restorations must not be placed on firing pins during cyrstallization
due to a risk of distortion of the restoraton. Therefore,
IPS Object Fix is used to position the restorations on the firing tray.
The cavity of the restoration has to be completely filled with
IPS Object Fix. Additional material is applied to form a base on which
the restoration is supported on the firing tray. (
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Can firing pastes other than IPS Object Fix be used in the crystallization
process?
IPS Object Fix has been specially developed for the crystallization of
IPS e.max CAD restorations. In other words, the consistency before
and after the crystallization allows the paste to be easily applied and
cleanly removed. Other pastes must not be used as they are not
easy to remove. Destructive blasting with Al2O3 or glass polishing beads
is necessary to remove the pastes. Furthermore, other pastes
may damage glass-ceramic surfaces because of their compositions. (
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Can other firing trays, eg "honeycomb" trays,
be used for the crystallization of IPS e.max CAD?
No other firing trays should be used, as the silicon nitride tray in
the matching assortment stores the heat, which is necessary to cool the
glass-ceramic slowly without building up tension. Other firing trays,
eg "honeycomb" trays, cannot store heat and therefore cool
down too
quickly, creating tension in the ceramic. (
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Can furnaces other than those from Ivoclar Vivadent be used to crystallize
IPS e.max CAD restorations?
The crystallization of IPS e.max CAD is specially coordinated with the
Ivoclar Vivadent ceramic furnaces (eg P200, P300, P500 and
EP 600 Combi). If you would like to use other, untested ceramic furnaces,
please consult Ivoclar Vivadent about their compatibility
with IPS e.max CAD. It is important to note that not any ceramic furnace
can be used for crystallization. Ceramic furnaces that do not
feature a controlled long-term cooling mode cannot be used for this purpose. (
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Can the crystallization quality of IPS e.max CAD restorations be controlled?
Optical checks can be conducted with the help of the accompanying material
shade guide. If the shade and opacity are comparable to
that of the material shade guide, the crystallization process has been
carried out successfully. The colours must always be compared on a
neutral background in incident light. If the colour and opacity of the
restorations are different from the shade guide, eg too translucent,
a new restoration must be milled. Crystallization cannot be repeated. (
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Can IPS e.max Ceram Margin materials be used with IPS e.max CAD?
IPS e.max Ceram Margin materials must not be used on glassceramics (IPS
e.max Press and CAD), as the firing parameters are
too high and the reduction for the shoulder would weaken the restoration. (
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Can IPS Empress Universal Shades, Stains and Glaze be used on IPS e.max
CAD?
IPS Empress Universal Shades, Stains and Glaze have been specially developed
for the IPS Empress System. They cannot be used with
IPS e.max products. (
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Can IPS e.max CAD frameworks be blasted with Al2O3 or glass polishing
beads before they are veneered or after
their completion (on the cavity
side)?
IPS e.max CAD restorations must not be blasted with Al2O3 or glass polishing
beads before veneering and placement, as this would
damage the ceramic surface and alter its properties. (
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How must the internal (bonding) surface of IPS e.max CAD restorations
be conditioned before cementation?
The internal (bonding) surfaces of IPS e.max CAD restorations must always
be etched with hydrofluoric acid etching gel (IPS Ceramic
Etching Gel) for 20 seconds, irrespective of whether they are cemented
with adhesive or conventional methods. The retentive
pattern created during etching generates a bond to luting composites
as well as glass ionomer cements. (
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Can IPS e.max CAD restorations be conventionally cemented?
IPS e.max single tooth restorations can be both adhesively luted and
conventionally cemented. If the restoration is to be conventionally
cemented, the tooth has to demonstrate adequate retentive preparation.
If this is not possible, adhesive luting should be
preferred, eg with Variolink¨ II or Multilink¨. Vivaglass¨ CEM
is available for conventional cementation. It is not advisable to use
classical phosphate cements, as they would negatively influence the light
transmission of the all-ceramic and therefore compromise the
aesthetic appearance of all-ceramic restorations. (
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