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CERECDOCTORS.COM
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QUARTER 3
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2015
C A S E S T U D Y
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B Y D AV I D R . E D E L S O N , D . M . D . , M . A . G . D . , D . I . C . O . I .
the main purpose for us as restorative dentists
is to replace damaged or diseased tooth structure with materials
that not only contain biological, physical and functional properties similar to those of natural teeth, but also have an esthetic
outcome as well.
Creating Natural-looking Restorations
Accepting the Challenge Using New Stain and Glaze Options
This becomes one of the greatest challenges CEREC doctors
and CAD/CAM dentists face in single-visit dental care: achieving
not only a natural-looking tooth restoration but one that will rival
a laboratory technician’s hand-fabricated esthetic restoration
from essentially a monochromatically colored, millable block.
It is also one of the biggest criticisms of CAD/CAM single-visit
dentistry.Withtheadvent of bothpressedandmilledporcelainresto-
rations, laboratories and dentists have had to change their thought
processes when working with porcelain and porcelain shading.
We are no longer reflecting color off of opaque metal alloy
frameworks or trying to resolve direct reflection and oxide migra-
tion issues. With milled porcelain restorations, the new challenge
becomes managing the illumination within the restoration and on
the restoration surface.
Since it is impractical to do cut-back and layering techniques
in the timeframe of a single-day appointment, we have to rely on
the block material’s color shade and our attempts to characterize
that block with shade pastes and stains. There are block manu-
facturers such as Ivoclar and Vident that do make color gradient
blocks for posterior and anterior restorations that help build the
incisal translucency and color depth naturally seen in teeth and
laboratory-technician-fabricated restorations.
These color gradient blocks that are available to CEREC clini-
cians are designed to reproduce the shading effects of trans-
lucency, chroma and lightness when positioning the designed
restoration in the pre-milled block within the CEREC software to
help recreate the appearance of dentin and the surrounding, more
translucent, enamel.
According to Vident, their blocks have increased fluorescence in
the cervical area that produces a natural shade effect within that
particular given block.
Ivoclar offers Empress Multi, a polychromatic block, that offers
the same fluorescent transition between the dentin and enamel
surfaces that provides restorations with a maximum of esthetics
and life-like appearance without the need necessarily for charac-
terization. To date, these are the only available blocks with color
transition within them, and firing of these blocks is optional —
so, therefore, is characterizing themwith shades and stains.
By having a block material with an inner dentin body and an
external enamel layer, it will, upon illumination, create the fluo-
rescence and opalescence phenomenon required to give tooth
color to that particular restoration. And that tooth color is directly
related to varying saturation levels of the inner dentin and the
outer translucent enamel. Therefore, the three-dimensional color
of a tooth that is perceived by the human eye consists of a balance
of fluorescence and opalescence.
Fluorescence in tooth structure is being defined as a tooth’s
ability to absorb light energy and deflect it in different wave-
lengths that create value in the tooth. So the optical characteris-
tics of natural teeth are therefore determined by the interaction
of light with the dentin and enamel. This includes the varying
degrees of translucency and opacity of both, along with opalescent
and iridescent effects, and of fluorescence as well.
However, for clinicians who prefer lithium silicate and zirconia-
basedmaterials, theoptions are currently limited tomonochromatic
block choices. Ivoclar has introduced a multicolor, polychromatic
pressible version of their e.max block material, but there currently
is no millable product edition available for CEREC users. In these
instances, we clinicians must rely heavily on the translucency of the
block material of choice — whether it is high translucency or low
translucency, and our shade and stain pastes and glazes.
Each block manufacturer provides a stain-and-glaze system
specific to their particular block. There are, however, third-party
producers of universal shades, stains and glazes. One such company
is Indenco Dental Products. The goal of any shading and glazing
system is to provide characterization and an external alteration of
light transmissionor fluorescence. Indenco’s Frit Systemis unique in
the art of shading ceramics (Fig. 1). Their polychromatic frits shading
systemutilizes crystal clear recrystallizing nano-particle technology
to allow for refraction illumination (rather than the more common
direct reflection shading systems). These frits have the ability to
refract light and, with the internal illumination of the crystals, add
