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30 | CERECDOCTORS.COM | QUARTER 4 | 2014
typically for posterior restorations, but
three other shades are available along
with accessory try-in pastes.
The crown was then seated fully into
place, and an equal amount of cement
was observed expressing from all areas
of the margins. (Lack of equal expres-
sion would indicate a void, creating the
potential for ingress of contaminants.)
Everyone has his or her own way of
doing clean-up, but this operator prefers
in most cases for crowns to let this mate-
rial reach its own gel set, which takes
approximately 60 to 90 seconds (Fig. 10).
This allows the material to be peeled off
in a rubbery state, after which smaller
amounts can be removedwith an explorer
and floss. Following this step, light curing
can be performed. One should be mindful
of reduced light transmission through
thicker areas of material with consid-
eration given to adequate light output
(>1200 mw) and of sufficient duration
generally judged as a function of focal spot
size and number of restored surfaces.
The immediate post-op photo shows
the nicely polished result of these steps
(Fig. 11). The adjacent restoration is an
e.max CAD crown, and it is difficult to
tell the difference between the two. The
color appears even more stabilized in
Figure 12, which exhibits the high gloss
of the Lava Ultimate material.
DISCUSSION
Cement is often not a high-profile
consideration for CEREC users but, as
demonstrated here, the right cement
can provide for a maximized clinical
outcome achievable in a very effi-
cient and easy-to-execute manner. A
Universal adhesive like Scotchbond
Universal makes adhesive cementation
a simple, two-component process for all
chairside CAD/CAMmaterials.
Glass ceramics chosen for strength
alone is a high-profile decision for
dentists. Some dentists will justify inad-
equate reduction of the preparation
by relying on a material’s reported
strength. The logic seems to be that a
stronger material will be more forgiving
if a preparation cannot be executed to
meet the specific thickness require-
ments of it. Attention to preparation
geometry, reduction/clearance and opti-
mized/reproducible adhesive technique
is the performance basis for every block
we use at the chair.
Fig. 10: The seated Lava Ultimate restor-
ative crown. Note the circumferential
excess of RelyX Ultimate cement in a
gel-set stage for easy clean-up
Fig. 11: Immediate post-op
Fig. 12: Final result
providing the desired clinical outcome.
The final result is indicative of this having
been performed in little more than one
hour of chair time, and exhibits an accept-
able, functional and esthetic outcome for
the treated tooth.
For questions and more information,
Dr. Poticny can be reached at
djpoticny@earthlink.net.
Optimizing these aspects will create
less need to focus on mechanical proper-
ties of the restorativematerial alone. This
case demonstrates the proper course of
action when the design proposal reveals
a problem with recommended thick-
ness — the dentist should refine the
preparation rather than expect the mate-
rial to compensate for the deficiency. It
also demonstrates that options exist to
the traditional all-glass materials when
greater material strength is still desired.
A reliable, predictable and optimized
outcome can be expected with proper
clinical technique for virtually any of the
“high-strength” block materials including
using a compatible adhesive system,
particularly Scotchbond Universal with
RelyX Ultimate adhesive resin cement.
Because the Lava Ultimate block requires
no firing and can be polished quickly, it
typically requires less chair timewhile still
| | | P O T I C N Y
10 11
12
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