DentaltownUK March 2018 - 33

Fig. 6: Lingual view shows the anatomical form
of the marginal ridges.

Fig. 7: The restorations displayed very good marginal
integrity straight out of the milling chamber.

restorations (Fig. 3). The software offers broad control of the contact size
(Figs. 4 and 5) and also enables the creation of very natural marginal ridges
(Fig. 6, see p. 94), which would not have been possible in a direct procedure.
The restorations were then milled from a high-translucency block.
Once milling was complete, the restorations were tried in the preps
to confirm fits (Figs. 7-8, see p. 94). Both restorations demonstrated very
good marginal integrity straight out of the milling chamber, displaying
precise fits all the way around the most intricate parts of the preparations.
A selective etch was then performed on the enamel of the preparations
(Fig. 9, see p. 94). I scrubbed 3M Scotchbond Universal Adhesive into the
preparations and on the intaglio surfaces of the restorations for 20 seconds.
The adhesive was then air-thinned and light-cured. I then applied 3M
RelyX Ultimate Adhesive Resin Cement to the restorations and they were
seated. Excess cement was tack-cured and removed, and final light curing
was then performed.
The patient was instructed to bite down on articulating paper and minor
adjustments were made to the occlusion. Final polishing of the restorations
was then completed.
The final results were restorations with excellent marginal ridges and
contours, which blended beautifully into the existing tooth structure. From
start to finish, this case was completed in just under an hour (Fig. 10).

Discussion

Fig. 8: Try-in on #31.

Fig. 9: Selective etch of enamel.

I am sometimes asked by other dentists why I would opt for an indirect
procedure in a case such as this, given that it probably takes 10 to 15 minutes
longer than a direct procedure would. My answer is that the process of creating
these restorations is more tolerable, and even enjoyable, when compared to
a direct procedure. The labor intensiveness of working with rings, bands
and wedges, placing and light-curing incremental layers of composite, then
sculpting and contouring can be a lengthy and involved process. This is
even setting aside the possibility of discovering a bad contact at the end
of the procedure and having to reopen the prep and pack material again.
Those procedures can be mentally taxing.
However, while an indirect restoration is being milled, I can spend the
extra 10 minutes doing a hygiene check or beginning another appointment,
so my time is not wasted. With the tedious work outsourced to the mill, a
morning full of appointments to treat interproximal decay becomes much
more enjoyable.
Another clear benefit is patients' response to the procedure, as evidenced
very well here. CAD/CAM procedures are the one thing I do in my practice
where I find that patients are consistently blown away. They become much
more interested in the procedure when they can see their scan being done
and watch restorations being designed and milled.
The availability of a milling material that is easy to adjust, requires no
firing, and that delivers great aesthetics and ideal marginal fits makes the
dentist's choice between direct and indirect treatment in situations like this
much easier. With the proper technique and bonding protocol, the Cerec
system can be used to efficiently deliver restorations that will stay in place
and looking great for years to come. n

Fig. 10: Final results. Note the disappearing margins versus
the obvious appearance of the old restoration on #30.

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