5 AESTHETICS
5.1 POSTERIOR TEETH
CEREC inlays and onlays can be characterized with the help of
ceramic
stains. After they have been glazed they can be placed in
the same way as laboratory-made ceramic restorations.
Due to the special qualities of the CEREC ceramics (chameleon-like
shade adaptation; wide choice of lightness, translucency and
colour shades), staining is not necessary in most situations.
The CEREC ceramics are easy to polish. In most cases the surface
finish is in no way inferior
to that of a glazed restoration.
Various studies testify to the good shade adaptation of CEREC
ceramics. According to the criteria of the California Dental Association
(CDA) 87% of the restorations were rated as excellent.
According to the USPHS, the surface characteristics and shade adaptation
of all the tested restorations were judged to be excellent or
clinically good.
CONCLUSION If the ceramic materials are correctly chosen and properly
polished, laboratory staining and glazing are unnecessary
in most cases.
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5.2 ANTERIOR TEETH
After they have been milled CEREC anterior crowns can be stained
and glazed. Alternatively, they can be incisally trimmed and then
layered using a transparent ceramic material (in cases where
especially transparent incisal surfaces are required).
Thanks to their graduated shading intensities, polychromatic
blocks (e.g. VITA Triluxe or Empress CAD Multi) make it easier to
imitate the natural teeth.
Shading pastes (e.g. VITA Shading Paste, Ivoclar Shade and Stains
Kit) and shading powders (e.g. VITA Akzent) permit the rapid characterization
of anterior crowns. In simple applications shading and
glazing can be combined in a single operation. Multiple firing operations
are possible.
The CORRELATION programm allows the shape of the restoration to
be simulated prior to milling. In many cases it is possible to create
and place chairside anterior crowns during a single appointment.
More sophisticated layering techniques are possible.
However, these usually necessitate an indirect procedure using a
physical impression and a cast model. Highly complex characterizations
can be achieved in this way.
CONCLUSION Anterior crowns pose a challenge which can be accomplished
during a single appointment with the help of polychromatic
blocks and various characterization techniques.
5.2.1 VENEERS
More and more CEREC users are offering veneers as part of their
treatment repertoire. Partial anterior crowns and veneers are
frequently used as a tooth-conserving alternative to a full crown.
Characterization can be performed using the methods described for
anterior crowns (ceramic stains in combination with transparent
ceramic layering materials).
In addition, “background shading” can be used in order to achieve
natural-looking results. In this case composite shading materials
are applied to the rear surface of the milled veneer. After the veneer
has been placed this shading is visible
through the thin sliver of
ceramic material.
Fine-tuning, contouring and high-gloss polishing are performed
after the veneer has been bonded to the tooth. The time input
corresponds to that of a CEREC inlay.
CONCLUSION CEREC veneers are a fast, tooth-conserving alternative to
anterior crowns.