Dentaltown November 2017 - 32

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case study

Let the Light In
Simple steps for achieving lifelike restorations.

by Daniel J. Poticny, DDS
Daniel J. Poticny, DDS, is an
adjunct clinical associate
professor at the University of
Michigan School of Dentistry,
department of cariology,
restorative sciences, and
endodontics, with a full-time
practice in Dallas.
He is an international presenter
and educator for digital dentistry and materials, adhesives
and cements, and restorative dentistry. He is widely
published on these topics in addition to performing original
and ongoing dental research.
Poticny also serves as a consultant and advisor to various
dental manufacturers and serves as an editorial board
member for multiple dental journals. He is a member of the
International Association for Dental Research, the Academy
of Computerized Dentistry and the American Dental
Association and its component societies.

32

NOVEMBER 2017 // dentaltown.com

Whenever a patient needs anterior
restorations, it is safe to assume that the
aesthetic demand will be quite high. The
objective of any clinician working on
anterior teeth is to make the treatment
look as innocuous as possible-as though
we were never there.
Consideration of material for anterior
crown applications involves aesthetics, the
condition and amount of supporting tooth
structure, the need to conceal dark cores
or non-matching stump shades, and the
presence of parafunctional habits. Full
ceramics are considered the gold standard
for these applications, but ceramics cover
a lot of territory because many factors
contribute to the selection of one ceramic
over another.
Veneered ceramics that are pressed or
layered over high-strength zirconia cores
are an option when metal substructures
are undesirable. Technically, these are
better described as porcelains (silica glass)
fused to polycrystalline ceramic (no glass
content) cores that can be used to mask
underlying conditions. This solution
is similar to how metal was used, but
eliminates the gray lines in gingival areas
and improves the dead look caused by
metal's opacity and opaquers used to
mask yellow or gray metal.
While zirconia is a definite improvement compared to the optical properties
of metals in terms of opacity, it too leaves
something to be desired in terms of toothlike light transmission, fluorescence and

Fig. 1. A 42-year-old female patient with
existing endodontics and restorative material
on teeth 8 and 9.

accurate shading. Most zirconia cores
are inherently white and must be shaded
with the use of dopants (coloring agents)
to reduce the stark white effect. In most
cases, pressed or milled ceramics would
yield better aesthetic results with the
proper application.
Although layered-over-core materials
have held their own for decades, the
veneered porcelain can chip because of
patient habits, accidental trauma and
incorrect laboratory fabrication. As a
result, monolithic zirconia is also widely
used for posterior applications and more
recently for crowns in the smile zone.
Being machined from a solid ingot,
block or puck with the promise of high
strength due to construction simplicity,
the one-piece construction principle
should render chipping as a virtual nonissue. Monolithic zirconia also allows
for minimally invasive preparations for
upper incisors requiring thin lingual with
very low abrasivity, much like metal was
previously used in areas with minimal
clearance and high stress.
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