Excellent temporaries

USERREPORT
DENTAL INC. Nov/Dec 2009
32
Excellent temporaries
User report on Structur 2 SC and Structur 2 Premium from VOCO
T
he use of acrylic and composite type
materials for the provisionalisation of
crown and bridge work has been well
established over many years and most materials on
the market today use a two part catalyst and base
system, combined with the now very common auto
mix syringe. This has resulted in easy to use, easy
to mix products combined with a simple and precise
delivery system.
To achieve success in crown and bridge work it
isessential to create temporaries which fulfill certain
criteria such as aesthetics (including tooth form),
occlusion, durability and quality of fit. The purpose
of this article is to look at how Structur 2 SC and
Structur Premium cope with meeting these goals.
Currently the most popular way of making
provisional restorations (where there is only a
relatively small amount of change to be made to the
existing structure) is to take a putty, or putty and
wash impression, of the existing tooth or restoration.
This simple and reliable method allows the
formation of a matrix which has enough elasticity to
be removed from undercuts and interproximal areas
without tearing or distorting, but adequate rigidity
to reproduce the original anatomy in considerable
detail (see Figure 1). This also has the advantage
that it can be kept in the surgery indefinitely, without
distorting, until the final restoration is ready. In the
unlikely event that the temporary is lost or fractures,
a new one can be quickly and easily made.
Figure 1: Case 1: Structur 2 SC temporary crown on tooth 46,
showing an accurate reproduction of the original crown (which
needed to be replaced due to recurrent distal caries).
Figure 2: Case 1: Soft tissue at fit stage with optimal soft tissue
collar.
Figure 3: Case 1: Emergence profile of new crowns.
Figure 4: Case 1: Crowns in situ
CLINICALREPORT
USERREPORT
TECHNOLOGY
MATERIALS
Figure 6: Case 2: Preoperative view with narrow buccal corridor
in the area 13 to 16.
Figure 5: Intro-Set Structur 2 SC (Self-curing temporary crown
and bridge material in cartridges).
Figure 7: Case 2: With Structur 2 SC temporaries in place on teeth
15, 14 and 13 only.
Figure 8: Case 2: Final porcelain veneer restorations on teeth 15,
14, 13 and 12.
Figure 9: Case 3: Pre-operative view.
DENTAL INC. Nov/Dec 2009
One of the most important aspects of successful
crown and bridge work is the soft tissue aes-thetic,
and the temporary restoration plays an extremely
important part in not only maintaining this but, in
certain situations, actually helping to develop a new
profile (see Figure 2 and 3).
If the final crown is to have a natural emergence
profile, the gingiva needs to be held in the de-sired
position. Failure to do so can, on some occasions,
result in recession and loss of aesthetics. Figures
2, 3 and 4 demonstrate how the accuracy of fit of
the temporary will allow maintenance of an ideal
gingival collar when preparing subgingival margins.
This type of result has been very easy to achieve
with Structur 2 SC as it is very accurate and has a
surface texture which is highly polymerized when
set and easy to polish. Having a polished, hard
margin helps to minimize the amount of bacteria
attracted to the surface while also being easier for
the patient to maintain.
One of the problems I have encountered over the
years is that most of the products available on the
market have different quantities of catalyst and base
in the syringe delivery system. This means that there
can be a slightly uneven mix of the two parts, with the
result that there is a slightly uneven polymerization
of the material. This leads to two problems. Firstly,
that the surface texture can be excessively tacky
which can make the temporary inaccurate and
hard to polish, and secondly, there can be hidden
weaknesses in the material which only become
apparent when the temporary restoration has been
in the mouth and under loading for a few days.
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USERREPORT
DENTAL INC. Nov/Dec 2009
34
Figure 10: Case 3: Diagnostic wax up.
Figure 11: Case 3: Temporaries allowing good visualization of
wax up, including surface texture detail making assessment of
changes far easier.
Figure 12: Case 4: Pre-operative view.
Figure 13: Case 4: Structur 2 SC temporaries with reline of margins
to allow ideal gingival contour.
VOCO has got around this problem by supplying a
material which is divided in two identical syringe
sizes of catalyst and base ensuring a much more even
mix and therefore an even set, significantly reducing
these problems (Figure 5).
Structur 2 is a flowable self-curing composite
with phased polymerisation. This allows for a
flexible stage where the material can still be removed
from minor undercuts before final hardness has
been reached, but without causing marked loss in
accuracy of fit. This can be extremely useful when
removing multiple units or bridgework. The setting
time is conveniently short and allows for final
trimming and polishing after just 3 minutes.
Alternatively, when there are more extensive
changes planned to either the occlusion or the aesthetics, a diagnostic wax up is often a better starting
point for the matrix. Again, the ability to accurately
reproduce this information in the mouth is essential
when assessing any aesthetic or occlusal changes to
be made. Structur 2 SC has proved to be very reliable
in this respect, as shown below in Figures 6-11.
One of the most common problems encountered
with provisional restorations when preparing
subgingivally is that they can have very thin fragile
margins. This is usually caused by the fact that once
the support provided by the hard tissue of the tooth
is removed, the soft tissue can collapse into the space
which is to be taken by temporary material.
As previously stated, an under-contoured crown
lacking in soft tissue support can be the reason
for minor tissue irritation and recession, resulting
in a loss of aesthetics at or shortly after the final
cementation stage.
To get around this problem it is often necessary to
add to the margins of the temporary restora-tion to
create a more ideal result.
Having a material such as Structur 2 SC allows
for easy adjustment, by simply applying a layer
of flowable composite or acrylic, as both materials
exhibit an extremely good bond with a near seamless
joint. Neither material requires any special bonding
technique which saves huge amounts of time, cost
and trouble.
THE ALTERNATIVE.
Light-curing posterior restorative
• Alternative: Large restorations without amalgam
• Quick: 4 mm layers are cured in 10 seconds
• Universal shade: Provides excellent match to the natural tooth shade
through chameleon effect
DENTAL INC. Nov/Dec 2009
NOW AVAILABLE
IN BULK PACK
35
VOCO GmbH · P.O. Box 767 · 27457 Cuxhaven · Germany · Tel. +49 (4721) 719-0 · Fax +49 (4721) 719-140 · www.voco.com
USERREPORT
Figure 14: Case 5: Preoperative view
Figure 15: Case 5: Temporary veneers using Structur Premium.
A high gloss finish was achieved not only at the fir preparation
stage, but also maintained 14 days later at the fit stage of the
final veneers.
Figure 16: Case 5: Preoperative view
ABOUT THE EXPERT
James Green, BDS graduated from Newcastle
Dental School in 1990 and is an experienced
practitioner in the field of aesthetic and restorative
dentistry. He is the Principal of a private practice in
Oxford, England and a former clinical demonstrator,
Department of Restorative Dentistry, Guys Hospital,
London. For the last seven years he
has been the principal lecturer and
hands-on instructor for courses in
Crown and Bridge technique and
regularly speaks on the subject
DENTAL INC. Nov/Dec 2009
36
Gross adjustment of Structur 2 SC can be easily
achieved using a coarse polishing disk without risk
of fracture of even fine knife edge margins. The final
polish is then achieved with either a fine disk or a
polishing mop to achieve a high luster finish.
Figures 14 -17 show the temporary veneers
using Structur Premium. A high gloss finish was
achieved not only at the fit preparation stage but also
maintained ten days later at the fit stage of the final
veneers.
Having worked with Structur 2 SC for several
years now I have been extremely impressed by the
strength of the material and have experienced very
few incidence of fracture, even when constructing
bridgework of up to six units in length. Obviously,
this is only the case when there has been adequate
reduction of the underlying tooth structure and the
overall bite has been carefully considered.
Lastly in the anterior region where patient are even
more conscious of the look of the new tem-poraries,
VOCO has introduced in 2005 a more aesthetic
temporary material called Structur Premium. This
material has a sub-micron filler system which has
distinct advantages in the ante-rior region as it can
be highly polished, as well as having improved
bonding characteristics when using it in situations
such as temporary veneers, where a degree of
bonding is required to retain the restoration.
Overall, I have been extremely impressed with
both these products from VOCO, and having tried
most of the other materials commonly available,
have found it to be the most reliable and cost
effective material of this type on the market and
would encourage anyone to give it a try.
Figure 17: Temporaries 14 days after placement.