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Fig. 9: Interfering contacts
Fig. 10: Colors and movements:•Centric/Occlusion
•Laterotrusion (side movement,
working side)
•Latero-Protrusion ( forward side
movement)
•Meditrusion (side movement,
balance side)
•Protrusion ( forward movement)
Fig. 11: Lower functionally generated
paths
There are a couple of ways to analyze
functional interferences created by the
virtual articulator. The most intuitive and
helpful is the “Occlusal Compass” (Fig. 10).
By the use of different color schemes, the
software can not only identify where the
interference is located, but alsowhich type
of movement created the contact point. A
function called “Articulation Animation”
is available to help visualize not only the
accuracy of the jaw movements, but also
howthese dynamicmovements impact the
design of your restoration.
Earlier it was discussed how the soft-
ware algorithms can reproduce different
ranges of contact movement to create
functionally generated paths (FGPs) for
each respective arch. The CEREC V4.2
software represents these FGPs by over-
laying the ranges of motion in purple. The
interferences on tooth #14 and #15 shown
by the Occlusal Compass can be seen
showing through the Lower FGP when
overlaid on the proposals (Fig. 11). After
adjusting all interfering and penetrating
centric contacts, the final proposals are
completed and ready to bemilled (Fig. 12).
Creating true virtual articulation
will not only help the user create more
successful restorations, but also help eval-
uate the patient’s entire occlusal scheme.
The applications for this analysis could
include: patient education, treatment plan-
ning and dynamic occlusion verification in
the software. For example, if we look at
the Occlusal Compass of a single hybrid
abutment/abutment crown on tooth #8
(Figs.13-14), we can see some slight protru-
sion and latero-protrusion interferences
in the proposal. Using the Articulation
Animation function, we can, in fact, verify
that those dynamic contact points exist in
protrusion (Fig. 15). The green arrow in
that photopoints to a functionalwear facet
on the lower central incisor (tooth #24).
Again using the Animation function, you
can see how the facet was likely created in
left excursive function (Fig. 16).
CEREC V4.2 has brought us many new
features. This article discussed one of the
more exciting and innovative ones with
VirtualArticulation.Moving fromthestatic
world to a dynamic one will not only bring
thequalityofourrestorativeocclusionfrom
good to great, but also opens the doors for
many exciting applications to come.Maybe
one day we will look at the year 2013 and
group it alongwith 2003 and 2009.
The author would like to thank Dr. Albert
Mehl for creating a reference to under-
stand the Virtual Articulation process
and Dr. Gary Dewood for his help and
general expertise regarding articulators.
For questions and more information,
Dr. Skramstad can be reached at
mike@cerecdoctors.com.
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