Lab Tribune Middle East & Africa No. 1, 2018

Lab Tribune Middle East & Africa No. 1, 2018

Familiar and yet completely different / Perfect walls

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Published in Dubai

January-February 2018 | No. 1, Vol. 8

www.dental-tribune.me

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Familiar and yet
completely different

www.me.dental-tribune.com/e-paper/
Vol. 8 • Issue 4/2017

issn 1616-7390

CAD/CAM
international magazine of

digital dentistry

2017

Interview with Werner Gotsch about Celtra® Press, the new
zirconia-reinforced lithium silicate ceramic by Dentsply Sirona
interview
“Dentistry has finally arrived in the digital age”

case report
Screw-retained implant-supported restoration
in the edentulous maxilla

cone beam supplement

By Dentsply Sirona
Every day, Master Dental Technician
Werner Gotsch faces the question of
what materials can help him keep
his laboratory in Marktleuthen, Bavaria – healthy and economically viable. Moreover, his customers, who
include dentists from all over the
country, expect more of him than
just “standard quality.” What they
do expect is individual, aesthetic,
precise fitting restorations made
from materials whose quality is beyond reproach. Werner Gotsch had
the opportunity to accompany the
development of the new zirconiareinforced lithium silicate ceramic,
Celtra® Press. In this interview, he
tells us what sets this material apart.

Mr. Gotsch, what prompted
you to get personally
involved in the development
of the Celtra® Press pressable
ceramic material?
Gotsch: To answer this question I
have to back up a bit, because there is
a fundamental issue we need to clarify first. I am talking about the general
role of pressable ceramics. To me,
these materials have the greatest potential – along with zirconia – when
it comes to creating highly aesthetic
and durable restorations. Their process-related variability and aesthetic
properties have now made pressable
ceramics indispensable in the dental
laboratory. However, despite all the
advantages of the material and the
associated procedures, all systems

on the market also have certain
shortcomings. So when Dentsply Sirona approached me with a request
to get involved in the development
of a new system that does not have
the known disadvantages of existing
systems, I agreed immediately.

layer on Celtra® Press objects. This
means that the objects can be easily divested using nothing but glass
beads and that, moreover, the objects will fit after divesting without
major finishing efforts. Which saves
considerable time.

It is probably not really that
fair to talk about the disadvantages of other products.
Let us talk about the
outstanding characteristics of
Celtra® Press instead. So what
are those, specifically?

You were talking about
aesthetics. How does Celtra®
Press measure up in this
regard?

I want to make one thing clear: there
are very good pressable-ceramic systems on the market. But if something
is already good, that does not at all
mean it cannot be improved further.
I myself am not a materials scientist.
I can only describe my impressions,
which I collected in an intensive testing phase and communicated to
the company. In simple terms, one
could say that the main advantages
are precision of fit and aesthetics.
Celtra® Press forms no reaction layer
on its surface, that is, at the interface
with the investment material. This
means that your divested structures
are the same as the one you invested.
This is impressive and of course has
a positive impact on the fit and the
precision of the pressed structures.
The reason for this is the special investment compound, a completely
new development that is part of the
Celtra® Press system and that prevents the formation of a reaction

The level of aesthetics that I achieve
with e.max®1 is already pretty impressive. Now I was given a material,
Celtra® Press, which claims to be a
further improvement on this aesthetic result. My honest opinion? I
thought that was just another one of
those typical marketing claims. But
then I found that Celtra® Press ingots
truly offer great shade fidelity. With
many pressable ceramics, the result
deviates from the initially selected
VITA®2 classical shade, so the objects
need to be adjusted by ornate staining to obtain the right shade. With
Celtra® Press you get the exact shade
after pressing that you selected in
the first place. In practice, that saves
me an incredible amount of extra
work. Add to this the material’s pronounced opalescence, which ensures
that the shade of the adjacent teeth is
“taken over” – downright absorbed, if
you want to put it that way.
This results in extremely high-quality aesthetic results – without timeconsuming reworks.

Are there any other
aspects that you would
like to highlight?
Let me remind you that I am not
a materials scientist. But in a close
cooperation with a research and development department you do end
up learning one thing or another. For
example, there is the high strength
of Celtra® Press that results from the
fact that the lithium silicate is reinforced with zirconia. This ensures a
strength of more than 500 MPa. And
this is why it is possible to produce
bridges up to the second premolar
with this material. The material is
very stable at the edges, and the marginal accuracy is very high. Moreover, I have never before encountered
a pressing material that flows as well
as Celtra® Press does – which makes
it possible to press even larger objects with only one sprue. So here
is another one of those points that
provide real added value to my laboratory, saving me time in sprueing,
separating and finishing.
All in all, Dentsply Sirona has succeeded in introducing a new pressable ceramic system that combines
excellent processing characteristics
with high strength and great aesthetics. This reduces my lab time, I get a
broader range of indications, and the
optical properties facilitate restorations whose appearance is in no way
inferior to the natural teeth.
Another advantage that I see is that
the IPS e.max®3 muffle system can
be used for Celtra® Press and that

Dynamic navigation for reliable
and predictable flapless implant placement

the material can be processed using
all commercially available pressing
furnaces. Therefore, no additional
capital investment is required in the
laboratory.

That sounds very enthusiastic. How would you describe
successful dental technology
today?
I would cite a phrase I often use at
the end of my lectures or one of my
workshops, a phrase that is more relevant today than ever: “Successful
dental technicians are characterised
by their passion for perfect restorations – and by their business acumen.”
1-3. Not a registered trademark of
Dentsply Sirona
The interview was originally published in Dental Dialogue VOLUME 16.

Polly Rutt
Regional Marketing Leader
Regional Commercial Organisation – EOC
– MEA
+971 56996 6052 (UAE)
+44 7792 156740 (UK)
polly.rutt@dentsplysirona.com
www.dentsplysirona.com

[2] => DTMEA_No.1. Vol.8_LT.indd

lab tribune

Dental Tribune Middle East & Africa Edition | 1/2018

Perfect walls
Photo: COLTENE

By COLTENE
In matters of aesthetics, dental technician David Zweifel would be a difficult man to surpass in a hurry. In
this interview, the experienced laboratory manager and material specialist from St. Gallen explains how
extremely thin walls can be created
without difficulty and why CAD/
CAM composite blocs are already
proving to be the new magic bullet
in everyday work.
Originally, the passionate expert
on aesthetics wanted to become a
goldsmith. Now he is busy creating “oral jewellery”: David Zweifel
of Switzerland has now spent over
30 years passionately working as a
dental technician in St. Gallen. In the
process, he has seen many a material
trend come and go. On the occasion
of his 30th anniversary of service, he
spoke to us about novel high performance composites, dentists resistant
to advice, and digitisation in modern
prosthetics.

Mr Zweifel, what must the
perfect dental material
deliver in your opinion?
D. Zweifel: The best dental material is still the natural tooth, wouldn’t
you say? Ideally, a state-of-the-art
material would offer properties as
close to dentine as possible, both in
terms of abrasion resistance as well
as gloss retention and durability.
At the same, the restoration should
provide a harmonious match to the
patient’s teeth and be gentle on the
opposing tooth. What good is a stable connection if the problem is only
transferred to the other jaw?
Fortunately, materials research has
recognised that a material with a low
modulus of elasticity dampens masticatory forces much better than the
traditional hard as steel restorations
of the 80s and 90s. If you like, we
are presently experiencing a renaissance of highly flexible composite
solutions.

Does that mean that the composite all-rounder will soon be
banishing ceramic completely
from the laboratory?
It is true to say that Reinforced Composite CAD/CAM blocs are presently
the rage. Dentists are already aware

of the advantages of this versatile
material from classical filling therapy. Nowadays, final inlays, onlays,
fully anatomical crowns and veneers
can be fabricated quickly and easily
from composite using the classical
CEREC manufacturing process. The
submicron hybrid composite blocs
are fast becoming an all-purpose answer in everyday lab routines.
During grinding, a modern composite material is far “better-natured”
than ceramic and is easier to shape.
Subsequent corrections in shade or
shape can be realised easily by the
clinician in his/her own practice,
which of course also meets the needs
of dentists. Overall, the accuracy of
fit of acrylic crowns is extremely
high and the flexible material fits
more harmoniously into the row of
teeth than brittle ceramic.

How about sculptability?
Which margin thicknesses
are possible with state-ofthe-art composites?
For example, I was able to play the
role of “midwife” for the innovative
BRILLIANT Crios submicron hybrid
composite material of Swiss dental
specialist COLTENE and was closely
involved in its development. During the lengthy fine tuning process, I
myself must have ground hundreds
of units. What impressed me most of
all: the walls of the fabricated pieces
were perfectly stable every time!
If you take a binocular look at the
margin accuracy, you can see that
even tapered restoration margins of
only 0.1 mm thickness can be ground
perfectly without becoming cragged. Flaking or even cracks are truly
a thing of the past. There is hardly a
material which offers so much opportunity for accurate work, a veritable delight for the Swiss soul.

Why is it that many dentists
are still wary of CAD/CAM
composite blocs?
Well, many dentists are not fully
aware, or only vaguely, of the progress composites have made during
the past ten years. They still remember the days of earlier mixing materials which were launched with considerable marketing ballyhoo and
claimed to be the ultimate solution.
Alone in 2016, I had to process guarantee cases for roughly CHF 5,000

of poorly conceived hybrid acrylics
where the mountings had not been
properly thought out at the time.
It is therefore quite obvious that clinicians who turn to me with such
revisions do not want to hear about
these “hybrid ceramics”!
In such cases, considerable powers
of persuasion are required to show
people what true CAD/CAM composite blocs can achieve these days.
Bonding is the same as for any other
filling: if I want to create a proper
monobloc, then I must always attach
a crown adhesively with a bonding
system that fits the tooth substance,
core build-up or abutment respectively; then I will end up with a good,
long-lasting solution.

How do you convince
customers who are resistant
to advice of the benefits of the
new restoration methods?
Those concerned need to experience the high quality themselves,
then they quickly become aware of
the high-quality solutions I can offer. Recently, a patient who was very
particular about shade and shaping,
wanted to have two of her anterior
teeth in the mandible done. Unfortunately, she had little time due to
the upcoming holidays. I made the
following proposal to the treating
dentist:
“I will grind two crowns as long-term
temporary restorations now for cementing.”
A BRILLIANT Crios milling bloc in
VITA shade A2 was used. The result
was a continuous smooth colouration from top to bottom without any
discolouration and a good match to
the overall picture of the mouth. After seven weeks, the patient was no
longer interested in any other type
of restoration. Currently, I have again
fabricated a partial crown with the
flexible CAD/CAM composite blocs.
After the try-in, the patient admitted not being able to detect anything
new in the mouth when exploring
with the tongue. The high wear comfort of the restorations convinces
even the most outspoken sceptics.

How much time do you save
when processing real CAD/
CAM composite blocs?
I would say, actually 50 to 70 % faster

when all is said and done – and with
a result that is far more aesthetic
than before. The entire firing process is eliminated and polishing is
unbelievably quick. As the name
implies, BRILLIANT Crios blocs have
an intrinsic fine satin gloss, e.g. they
require little in terms of processing. As a rule, I would recommend a
two-step approach to beginners: first
coarse grinding and then the use of
two special fine grinders.
Using the “Extra Fine“ grinding
mode of my CEREC MC XL, the
crowns turn out even more beautiful
than with the fast mode.

Doesn’t increasing digitisation
and the permanent use of
CAD/CAM in everyday lab
routines rob dental
technicians of their creativity?
Not at all, CAD/CAM technology is an
excellent support for daily work!
Whereas I used to have to tediously
apply wax, I can now support cusps
exactly and set minimum layer
thicknesses. I have become more efficient and at the same time deliver
better results - what a dream combination! Despite all the craftsmanship in our profession, one cannot
afford to be blind with regard to the
new media. 3D printing may not be
fully matured yet, but such methods
will continue to dictate and facilitate
our work.
When I saw the first CAD/CAM devices at the IDS years ago, I wanted to be
part of their development right from
the beginning. At the time I said to
my wife that the amortisation costs
would certainly not stop me, or, in
the words of the Swiss Railways: “I
am boarding the train now and I am
not going to wait until it arrives in
Geneva.” Reservations about the initial outlay proved entirely unjustified in retrospect: I had already easily
surpassed the break-even point after
only half the calculated time.

In other words:
Modernisation pays off...
Absolutely! It never hurts to expand
one’s service portfolio! Unfortunately, these days people always tend to
look at the price first. The daily battle
against the “cheap is cool” mentality also affects us in the laboratories,
but one should is not much more
expensive than a steel denture with

mounting. And if I can mill two
crowns from a size 14 CAD/CAM
composite bloc instead of one, then
the material costs are completely
different. Those wishing to check the
sums should simply make sure to
use the right numbers.

And last but not least, how
do you view the future of
dental laboratories?
If you project the present advances
in materials research into the future,
then dental materials will become
even more accurate and reliable
with regard to the special properties of human teeth. Meanwhile, the
high performance composites keep
offering better quality and more
attractive shades, but who knows,
maybe we will end up growing bioregenerative materials in our own
laboratories. The dental technician
as craftsman and artist will definitely
not be redundant!
I also have an abundance of ideas for
other product innovations: among
other things, I personally would find
tricoloured CAD/CAM composite
blocs a highly attractive proposition
for the future, where I could always
be aware of what one is comparing.
For example, I recently had to make
an affordable proposal for a patient
on social benefits. He did not wear
dentures and refused a gold-zirconium bridge for cost reasons. Finally, I
ground a titanium framework and
veneered it with composite blocs.
After grinding the crowns and bonding everything, the appearance was
sensational - nearly like real ceramic,
but in contrast, the dentures were
reimbursed without any problems
by the health insurer. A “high quality long-term temporary restoration” position enamel, dentine and
neck dentine as with ceramic before
grinding crowns or inlays. In the long
term, I look forward to being surprised by the next smart solutions
created by our Swiss dental specialists as well as specialists from around
the world.
When the time has come, I will definitely be there, readily waiting at the
“railway station” ...

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