Page 32 - CEREC Q3 | 2014

30 | CERECDOCTORS.COM | QUARTER 3 | 2014
with the release of chairside
software version 4.2 last year, dentists
now have the opportunity to create
custom implant abutments and
crowns in-office. The software is
very intuitive, and the process is
relatively straightforward and
rewarding on several levels.
The custom restorations can be
turned around in days and are
done for a fraction of the costs
involved when working with a
dental laboratory.
With so many block materials avail-
able to the CEREC dentist, it is easy to
become confused as to which material
to use in different clinical situations.
With implant-supported crowns, we
have been trained to use the strongest
material possible — often sacrificing
esthetics. Ask most restorative dentists
which ceramic material they are using
over their implants, and they will
answer that they are primarily using
lithium disilicate or even zirconia. Both
materials are excellent choices for this
application. The materials are among
the strongest in this class, and can be
customized and fired for excellent
esthetics.
But how strong is strong enough?
Compressive strength of ceramics can
only reveal a part of the story when it
comes to providing long-term natural
restorations over implants. Materials
such as zirconium and
lithium disilicate have
very impressive compres-
sive strength. Where these
Multiple CustomAbutments
and Crowns with CEREC
A Discussion About a New Class of Dental Ceramics
Offering Interesting Choices
CASE STUDY ||| BY BOB CONTE, D.M.D.
lead to premature screw failure, restora-
tion fracture or TMJ discomfort due to
parafunction.
In the last few years, a new class of
dental ceramics has emerged, offering
some interesting choices. These
so-called hybrid materials are a combi-
nation of ceramic and composite resins.
They combine many of the attractive
properties of ceramic, namely compres-
sive strength, wear-resistance and
esthetics with some of the best attributes
of composite resin, which are flexural
materials have a slight weakness is in
their lower flexural strength and their
higher wear rate to the opposing denti-
tion. Implants, unlike natural teeth that
sit in a cushioned periodontal ligament,
are essentially fused to the jaw bone
once osseointegration has occurred.
There is no flex to an implant. For this
reason, it is critical that the practitioner
creates a restoration with highly accu-
rate occlusal contacts when placing a
very “strong” ceramic over an implant.
Anyocclusal interferencecanpotentially
VITA ENAMIC NETWORK STRUCTURE
CERAMIC + POLYMER = HYBRID CERAMIC 1
Fig. 1: Vita Enamic is the first dental hybrid ceramic with a dual network structure.
The ceramic network or matrix is reinforced by a polymer network with each network
penetrating the other to create a true hybrid material. In addition to exceptional
elasticity, this hybrid ceramic also exhibits excellent adhesive strength after bonding.