DentaltownUK March 2018 - 32

CAD/CAM procedures are the
one thing I do in my practice
where I find that patients are
consistently blown away.
I have found that it creates superior margins even in difficult areas,
and the high translucency of the blocks allows the color from the tooth to
radiate through and make margins virtually disappear. Final finishing and
polishing can be time-consuming for some indirect restorations, but the
material used here has a familiar, resinlike feel under the handpiece and
polishes up very nicely.
Bonding is, of course, an important consideration for an indirect treatment,
but with simple attention to detail and use of the right materials, dentists
can alleviate many problems that come with this step. Fourth-generation
bonding agents that use a separate etching step have always provided the
strongest bonds, but can lead to postoperative sensitivity. The adhesive in
this system helps reduce some of those worries with a moisture-tolerant
feature that provides strong bonds and low sensitivity, even in total-etch
and selective-etch procedures.
The case seen here demonstrates the use of 3M Lava Ultimate restorative
and a proper bonding protocol to create aesthetic inlays with the Cerec system.

Fig. 1: The patient had an existing amalgam restoration
on #32 and a composite restoration on #31.

Fig. 2: View of the scanned preps in the Cerec software.

Case presentation
The patient had small direct restorations in need of replacement on #31
and #32 (Fig. 1). The wisdom tooth was in function, so the patient didn't
want it removed. While treatment with another direct procedure would
have been acceptable, it was determined that inlays milled from restorative
would be a better choice because this type of restoration results in better
margins and contacts.
The patient requested the teeth be treated with Cerec restorations,
because she had experienced the procedure before and preferred the results
to direct restorations. I would have recommended indirect treatment in this
case regardless, but the patient's preference was a nice vote of confidence
in the procedure.
The existing restorations were removed and small preparations were
created to allow for 1.5mm of material thickness through the fissure line.
A tapered diamond bur was used to create an 8-degree taper at the margins.
The Cerec scanner was then used on the quadrant (Fig. 2). In this case,
the opposing arch and a bite scan were not taken. This was possible for
several reasons. First, there were no cusps being replaced. In situations like
this, the Cerec software is capable of mimicking the anatomy of the teeth
closely enough to create a restoration that fits within the contours of the prep.
Additionally, the restorative is easy to adjust using articulating paper, just
as is done with direct composite. In cases where it is appropriate, forgoing
these extra scanning steps can help the process move more quickly, but in
cases with bigger areas of decay or when cusps that are in function with the
opposing arch become involved, more thorough scanning should be done.
Once the scan was completed, the software was used to design the

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MARCH 2018 // dentaltownuk.com

Fig. 3: The software's proposed restorations.

Fig. 4: Design of the contacts.

Fig. 5: The software allows excellent control of the contact size.
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