Although porcelain fractures
on crowns and bridges are
usually caused by accidents
or patient behavior, the burden for
these mishaps often falls on the
shoulders of the dentist. Considering the
high cost of crown and bridge
restorations, it is understandable
that patients will expect a reasonably
priced solution.
When faced with these situations,
I always inform the patients
that no repair will be as strong as the
original restoration. Fortunately,
materials such as the Embrace products
from Pulpdent are now available.
In my practice, these materials
have produced great success. I have
been using Pulpdent’s Embrace Restoration
& PFM Repair Kit with good results for 2 years.
In the following case, the patient
fractured the mesial-occlusal-buccal
portion of the lower left first molar
pontic (No. 19) on a 6-unit PFM
fixed bridge (Figure 1). This was unusual
because the patient has passive
occlusion on this tooth and no other
porcelain fractures were noted. The
fracture was noticeable when the
patient smiled. If allowed to remain,
the cracked, exposed porcelain
would continue to chip away. It
needed to be repaired to maintain
the integrity of the bridge and satisfy
the patient’s esthetic needs.
It is important to create as much
mechanical retention as possible to
have the best chance for a successful
repair.1 Roughing up the metal surface
with a fine diamond is imperative, and undercuts are valuable for
retention form (Figure 2).
Figure 1 — Shows fracture of the mesialocclusal-
buccal portion of the lower left first
molar pontic (tooth No. 19) on a 6-unit
porcelain-fused-to-metal fixed bridge. |
 |
Figure 2 — Kool-Dam was used to protect the gingiva and isolate the area to be repaired, ensuring a dry field and masking areas not
to be etched. |
Before etching the porcelain,
make sure that the soft tissue is protected.
Isolation with cotton rolls or
a rubber dam is recommended. In
this case, Kool-Dam light-cured liquid dam (supplied in the kit)
was used to protect any exposed tissue
(Figure 2). Kool-Dam stays cool,
remains flexible when cured, and is
easily removed in 1 piece.
A valuable tip when doing this procedure is to
extend the etched porcelain surface
beyond the fractured surface and
onto the smooth porcelain. I do this
routinely in these kinds of cases to
increase the etched surface area for
bonding and retention (Figure 3).
Figure 3 — Pulpdent Porcelain Etch Gel
(yellow) was then applied for 2 minutes. |
Also included in this new system is
Embrace First-Coat. According to
the manufacturer’s instructions, First-
Coat is a light-cured resin primer
that replaces silane and metal adhesives
and is placed on both the
porcelain and metal surfaces. Since
the 1980s, dentists have used silane
to act as a coupling agent to enhance
the bond between inorganic porcelain
and the organic resin used to
repair the fractured crown. I have
always suspected silane to be the
weak link in traditional repair techniques,
and my experience, as well as
among others’ suggests there is limited
and inconsistent success with the
old silane systems. In my opinion
Embrace First-Coat represents the
first significant improvement in
porcelain repair in 2 decades, and it
has provided a dramatic increase in
success rates in my practice. In vitro
shear bond strength testing by the
manufacturer indicates that the bond
between First-Coat and porcelain is
stronger than the cohesive strength
of porcelain itself at the resin–porcelain
interface. Clearly this is the key
factor.
Figure 4 — After etching, rinsing, and drying,
Embrace First-Coat was applied to the etched
and abraded surfaces with a brush applicator,
thinned with a gentle stream of air, and lightcured
for 20 seconds. |
After applying First-Coat (Figure
4), Embrace Opaquer, which
cures in just 20 seconds, can be used
to mask metal or discolored surfaces
(Figure 5). Heraeus Kulzer’s Venus composite resin was placed over
the opaque layer and light-cured for
20 seconds (Figure 6). The restoration
was then contoured and finished
using SS White finishing burs
and polished with Clinician’s Choice Groovy Diamond Polishing Brushes.
Figure 5 — Embrace Opaquer was placed in
the center of the exposed metal and carefully
spread with an explorer so that it was not on
the beveled porcelain margin. The opaquer
was light-cured for 20 seconds. |
|
Figure 6 — Venus composite resin (Heraeus
Kulzer) was placed over the opaque layer and
light-cured for 20 seconds. |
Next, Seal-n-Shine was used to seal
the margins against microleakage
and provide the final finish and polish
to the composite and porcelain
surface (Figure 7).
Figure 7 — A final finish is achieved with
Embrace Seal-n-Shine, which was light-cured
for 20 seconds. |
Conclusion
As dentists, we are always seeking
ways to improve the ability to
provide much needed services to
patients. In cases involving porcelain
fractured off of PFMs and all ceramic
restorations, dentists are now able
to provide a better solution than ever
before. The Embrace Restoration &
PFM Repair Kit offers new materials
to solve a problem that we face year
in and year out. lc
References
1. Kurtzman GM, Schneider AL. A technique
for repair of a fractured porcelain-fused-tometal
bridge. Dent Today. 2006;25(1):94-95.
