Ivoclar Vivadent IPS e.max CAD Chairside v.1 - Handbuch (Seite 97)

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If a plaster working model is used to work
with, which type of plaster should be used to
fabricate the model?
The directions of the manufacturers 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 chairside or
IPS Contrast Spray labside immediately before the
scanning procedure.
What kind of preparation requirements must
the die demonstrate in order to produce
accurately fitting restorations?
The preparation guidelines for all-ceramic restora-
tions apply to IPS e.max CAD. The thickness of the
incisal edge of prepared anterior teeth (upper and
lower) 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.
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.
Why is it necessary to determine the shade
of the tooth after preparation?
It is necessary to know the shade of the
prepared tooth because, depending on
the translucency level of the block
used, the shade of the prepared
tooth may have an influence on the seated all-
ceramic restoration. The appropriate block can be
selected using the IPS Natural Die shade guide.
In what situations are IPS e.max CAD HT
blocks used?
Given their high translucency, HT blocks are ideally
suitable for the fabrication of smaller restorations
(e.g. inlays and onlays). Restorations made of HT
blocks convince users with their true-to-nature
chameleon effect and the exceptional adaption to
the remaining tooth structure. The brightness
may be lower if translucent blocks are used to
fabricate larger restorations (e.g. crowns). In such
cases, it is recommended to use blocks with lower
translucency levels (IPS e.max CAD LT).
In which situations are IPS e.max CAD LT
blocks used?
Due to their high brightness values compared to
the HT blocks, LT blocks are ideally suitable for the
fabrication of larger restorations (e.g. anterior and
posterior crowns). IPS e.max CAD LT restorations
convince users with their lifelike brightness value
and chroma. This prevents the incorporated
restorations from greying.
Does the occlusal surface of IPS e.max CAD
restorations have to be ground after the
CAD/CAM processing?
Yes. In order to smooth out the
surface structure created by the
CAD/CAM milling, the occlusal
surface and particularly the func-
tional areas which show antago-
nist contact must be surface-
ground with fine diamonds.
Should manual adjustments with grinding
instruments be done before or after
crystallization?
Corrections by grinding should always be carried
out on the blue restoration prior to crystallization.
In doing so, it must be ensured that the restora-
tion is processed using only suitable grinding
instruments, low speed and light pressure to
prevent delamination and chipping at the edges in
particular.
e.max
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Questions and answers
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